The Netter Collection of Medical Illustrations VOLUME 5

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THE NETTER COLLECTION

of Medical Illustrations
Second Edition

Reproductive System
Endocrine System
Respiratory System
Integumentary System
Urinary System
Musculoskeletal System
Digestive System
Nervous System
Cardiovascular System

The ultimate Netter
Collection is back!

Netter’s timeless work, now arranged
and informed by modern text and
radiologic imaging!

The long-awaited update of The Netter Collection of Medical
Illustrations, also known as the CIBA “green books,” is now
becoming a reality! Master artist-physician, Carlos Machado,
and other top medical illustrators have teamed-up with
medical experts to make the classic Netter “green books” a
reliable and effective current-day reference.
• Apply a visual approach—with the classic Netter art, updated

illustrations, and modern imaging-- to normal and abnormal body
function and the clinical presentation of the patient.
• Clearly see the connection between basic and clinical sciences
with an integrated overview of each body system.
• Get a quick understanding of complex topics through a concise
text-atlas format that provides a context bridge between general and
specialized medicine.

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Presenting the latest editions of…

Now also available!
Netter’s Anatomy

Atlas for iPad

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Frank H. Netter, MD John T. Hansen, PhD
Atlas of Human Anatomy, Netter’s Anatomy Flash Cards,
5th Edition, 9781416059516
3rd Edition, 9781437716757

More great Netter resources...

FLASH CARDS
Ź Netter’s Musculoskeletal Flash Cards, 9781416046301
Ź Netter’s Advanced Head & Neck Flash Cards, 9781416046318
Ź Netter’s Physiology Flash Cards, 9781416046288
Ź Netter’s Histology Flash Cards, 9781416046295
Ź Netter’s Neuroscience Flash Cards, 2nd Edition, 9781437709407

HANDBOOKS/POCKETBOOKS
Ź Netter’s Clinical Anatomy, 2nd Edition, 9781437702729
Ź Netter’s Concise Radiologic Anatomy, 9781416056195
Ź Netter’s Concise Orthopaedic Anatomy, 2nd Edition, 9781416059875
Ź Netter’s Concise Neuroanatomy, 9781933247229
Ź Netter’s Surgical Anatomy Review P.R.N., 9781437717921

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VOLUME 5

The Netter Collection

OF MEDICAL ILLUSTRATIONS

Urinary System

2nd Edition

A compilation of paintings prepared by
FRANK H. NETTER, MD

Edited by

Christopher R. Kelly, MD

Postdoctoral Residency Fellow
Department of Medicine
NewYork–Presbyterian Hospital
Columbia University Medical Center
New York, New York

Jaime Landman, MD

Professor of Urology and Radiology
Chairman, Department of Urology
University of California Irvine
Irvine, California

Additional Illustrations by Carlos A. G. Machado, MD

CONTRIBUTING ILLUSTRATORS
John A. Craig, MD
James A. Perkins, MS, MFA
Tiffany S. DaVanzo, MA, CMI
Anita Impagliazzo, MA, CMI

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS: 978-1-4377-2238-3
URINARY SYSTEM, Volume 5, Second Edition

Copyright © 2012 by Saunders, an imprint of Elsevier Inc.

No part of this publication may be reproduced or transmitted in any form or by any means, electronic
or mechanical, including photocopying, recording, or any information storage and retrieval system,
without permission in writing from the publisher. Details on how to seek permission, further
information about the Publisher’s permissions policies and our arrangements with organizations such as
the Copyright Clearance Center and the Copyright Licensing Agency, can be found at our website:
www.elsevier.com/permissions.

This book and the individual contributions contained in it are protected under copyright by the
Publisher (other than as may be noted herein).

Permissions for Netter Art figures may be sought directly from Elsevier’s Health Science Licensing
Department in Philadelphia PA, USA: phone 1-800-523-649, ext. 3276 or (215) 239-3276; or email
[email protected].

Notices

Knowledge and best practice in this field are constantly changing. As new research and experience
broaden our understanding, changes in research methods, professional practices, or medical
treatment may become necessary.

Practitioners and researchers must always rely on their own experience and knowledge in
evaluating and using any information, methods, compounds, or experiments described herein. In
using such information or methods they should be mindful of their own safety and the safety of
others, including parties for whom they have a professional responsibility.

With respect to any drug or pharmaceutical products identified, readers are advised to check the
most current information provided (i) on procedures featured or (ii) by the manufacturer of each
product to be administered, to verify the recommended dose or formula, the method and duration of
administration, and contraindications. It is the responsibility of practitioners, relying on their own
experience and knowledge of their patients, to make diagnoses, to determine dosages and the best
treatment for each individual patient, and to take all appropriate safety precautions.

To the fullest extent of the law, neither the Publisher nor the authors, contributors, or editors,
assume any liability for any injury and/or damage to persons or property as a matter of products
liability, negligence or otherwise, or from any use or operation of any methods, products,
instructions, or ideas contained in the material herein.

ISBN: 978-1-4377-2238-3

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ABOUT THE SERIES

Dr. Frank Netter at work. Dr. Frank H. Netter exemplified the CUSHING’S SYNDROME IN A PATIENT WITH THE CARNEY COMPLEX
distinct vocations of doctor, artist,
The single-volume “blue book” that paved the way for the and teacher. Even more important— Carney complex is characterized
multivolume Netter Collection of Medical Illustrations he unified them. Netter’s illustrations by spotty skin pigmentation.
series affectionately known as the “green books.” always began with meticulous research Pigmented lentigines and blue
into the forms of the body, a philosophy nevi can be seen on the face–
THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS that steered his broad and deep medical including the eyelids, vermillion
understanding. He often said: “Clarifi- borders of the lips, the
cation is the goal. No matter how beau- conjunctivae, the sclera–and the
tifully it is painted, a medical illustration labia and scrotum.
has little value if it does not make clear
a medical point.” His greatest challenge Additional features of the
and greatest success was charting a Carney complex can include:
middle course between artistic clarity
and instructional complexity. That suc- Myxomas: cardiac atrium,
cess is captured in this series, beginning cutaneous (e.g., eyelid),
in 1948, when the first comprehensive and mammary
collection of Netter’s work, a single Testicular large-cell
volume, was published by CIBA Phar- calcifying Sertoli cell tumors
maceuticals. It met with such success that over the Growth-hormone
following 40 years the collection was expanded into secereting pituitary adenomas
an 8-volume series—each devoted to a single body Psammomatous
system. melanotic schwannomas
In this second edition of the legendary series, we are
delighted to offer Netter’s timeless work, now arranged PPNAD adrenal glands are usually of normal size and most are
and informed by modern text and radiologic imaging studded with black, brown, or red nodules. Most of the pigmented
contributed by field-leading doctors and teachers from nodules are less than 4 mm in diameter and interspersed in the
world-renownedmedical institutions, and supple- adjacent atrophic cortex.
mented with new illustrations created by artists working
in the Netter tradition. Inside the classic green covers, A brand new illustrated plate painted by Carlos Machado,
students and practitioners will find hundreds of original MD, for The Endocrine System, Volume, 2e.
works of art—the human body in pictures—paired with
the latest in expert medical knowledge and innovation Dr. Carlos Machado at work.
and anchored in the sublime style of Frank Netter.
Noted artist-physician, Carlos Machado, MD, the
primary successor responsible for continuing the Netter
tradition, has particular appreciation for the Green
Book series. “The Reproductive System is of special signifi-
cance for those who, like me, deeply admire Dr. Netter’s
work. In this volume, he masters the representation of
textures of different surfaces, which I like to call ‘the
rhythm of the brush,’ since it is the dimension, the direc-
tion of the strokes, and the interval separating them that
create the illusion of given textures: organs have their
external surfaces, the surfaces of their cavities, and
texture of their parenchymas realistically represented. It
set the style for the subsequent volumes of Netter’s Col-
lection—each an amazing combination of painting mas-
terpieces and precise scientific information.”
Though the science and teaching of medicine endures
changes in terminology, practice, and discovery, some
things remain the same. A patient is a patient. A teacher
is a teacher. And the pictures of Dr. Netter—he called
them pictures, never paintings—remain the same blend
of beautiful and instructional resources that have guided
physicians’ hands and nurtured their imaginations for
more than half a century.
The original series could not exist without the dedi-
cation of all those who edited, authored, or in other
ways contributed, nor, of course, without the excellence
of Dr. Netter. For this exciting second edition, we also
owe our gratitude to the Authors, Editors, Advisors,
and Artists whose relentless efforts were instrumental
in adapting these timeless works into reliable references
for today’s clinicians in training and in practice. From
all of us with the Netter Publishing Team at Elsevier,
we thank you.

v

ABOUT THE EDITORS

Christopher Rehbeck Kelly, MD, is a postdoc- Jaime Landman, MD, is Professor of Urology
toral residency fellow in the Department of Medi- and Radiology and Chairman of the Department
cine at New York–Presbyterian/Columbia University of Urology at the University of California, Irvine. Dr.
Medical Center. He received his undergraduate educa- Landman is an expert in minimally invasive urology
tion at Columbia College, where he was elected to Phi and kidney cancer and has published over 180 peer-
Beta Kappa, and his medical education from Columbia reviewed manuscripts on these topics. Dr. Landman
College of Physicians and Surgeons, where he was received his undergraduate education at the University
named valedictorian, elected to Alpha Omega Alpha, of Michigan, his medical education at the Columbia
and awarded the Izard Prize in Cardiology. He has University College of Physicians and Surgeons, and
authored numerous original scientific research papers then completed his internship (in General Surgery)
and review articles. In addition, he has published a and residency (Urology) at Mount Sinai Hospital in
cookbook entitled Mantra with chef Jehangir Mehta, as New York City. He then completed a fellowship in
well as articles about popular culture for Spin and minimally invasive urology under Dr. Ralph V. Clayman
Rolling Stone magazines. He is also a former producer at Washington University and remained there as the
and writer for The Dr. Oz Show on both syndicated Director of Minimally Invasive Urology. He returned to
television and satellite radio. He lives in New York City New York to the Columbia University Department of
with his wife, Leah, and their two dogs. Urology, where he spent 6 years before taking his
current position as the Chairman of the University of
California, Irvine. He is married to his wonderful wife,
Laura (who he does not deserve), and has one beautiful
daughter, Alexandra Sofia.

vi THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

PREFACE

All physicians have at some point in their career disease processes in new ways, their appearance re-
studied the illustrations of Frank Netter. His Atlas mains the same. Some important new concepts,
of Human Anatomy is indisputably one of the most however, Netter could not possibly have foreseen. In
beloved books in medicine, to the point that purchasing these instances we have relied on his talented team of
it has become a rite of passage for a new medical successors, who have created many new illustrations for
student. this edition.

Many are unaware, however, that the Atlas represents We have tried to make the text, like the illustra-
only a tiny fraction of the illustrations Netter created tions, both lucid enough for a medical student yet
during his lifetime. In fact, during his long and produc- sophisticated enough for an experienced clinician. By
tive career, he produced over 20,000 illustrations editing the text from opposite poles of the professional
depicting the anatomy, histology, physiology, and spectrum—one of us is a professor and department
pathology of nearly every organ system. chairman, the other a medical intern—we have tried to
ensure this would happen by design, and not by hopeful
Many of these illustrations were first published accident. Nonetheless, given the rapid pace of discov-
several decades ago in the “green book” series. The ery, we expect the text will not age nearly as well as the
original edition of this volume—known as Kidneys, illustrations.
Ureters, and Bladder—covered an impressive number of
topics, ranging from nephrotic syndrome to nephrec- We would like to thank the many talented physicians
tomy. Since its last revision in 1973, however, innumer- and scientists who contributed to this book. We are
able advances have been made in the fields of nephrology particularly indebted to Jai Radhakrishnan, Jeffrey
and urology. As a result, even though the original Newhouse, Leal Herlitz, Arthur Dalley, and Peter
edition has retained its historical importance, it has lost Humphrey for their extensive and tireless efforts.
much of its relevance to the modern clinician.
We would also like to thank our families—and espe-
In this new edition, we have attempted to reframe cially our wives, Leah Kelly and Laura Landman—for
Netter’s illustrations in the context of modern clinical their patience and support during the 2 years we spent
practice. We have reorganized the various components writing and editing this book.
of his illustrations based on current clinical concepts,
and we have complemented them with hundreds of new Christopher R. Kelly, MD
radiographic and pathologic images. New York, New York

In many instances, we have been struck by how accu- Jaime Landman, MD
rate many of the original illustrations remain. As Netter Irvine, California
himself once said, “anatomy hasn’t changed, but our November 2011
perceptions of it have.” Indeed, even as we understand

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS vii

ABOUT THE ARTIST FROM THE FIRST EDITION

When you first meet Frank Netter, you are a little expression capable of traversing the barriers of lan- lured into an emotional association with the scene.
surprised. You expect a man who has devoted a guage, culture, and time in order to communicate. An Artistic license might be taken with shadows and
lifetime to painting such magnificent medical art to be artist who chooses to use brush and canvas leaves a part highlights to make a medical point, time might be
outgoing, talkative, bursting with ideas. Instead, Frank of his inner self in the medium. His message may be compressed to show the dynamic continuance of
Netter is quiet, reserved, almost reticent. To carry the simple, direct, obvious, and reach many, or it may be clinical disease, but always the message was clear.
conversation, you appear to do all the talking, he speaks complex, hidden, obscure, and touch only a few. Always the clinical detachment, the hallmark of medical
little, listens a lot. Slowly, you realize that the greatest objectivity, remained. Accuracy was never compro-
talent of this world famous physician-artist is neither When young Frank Netter studied at the Sorbonne, mised for effect.
medical nor artistic. For Frank H. Netter, MD, is per- he was very much an artist. His canvases were the
haps the world’s greatest interpreter and communicator expressions of his essence. When young Dr. Netter Frank Netter maintains a tremendous mental pace.
of medical knowledge through the medium of art. To savored the beauty of the East River and the Brooklyn In 25 years he has produced in excess of 2,300 paintings,
interpret he must understand, to understand he must skyline from a window of Bellevue Hospital, the artist’s a rate which means a new painting every four days,
absorb information, and so he listens. love of form and color and life guided his spirit. With day in, day out, week after week, month after month.
the skill and talent of an artist his hands expressed what Each painting is detailed, thorough, accurate. Each is
As a means of communication, art is as old as his eyes saw and his soul felt, and when he finished, a researched, planned, sketched, checked, rethought, and
civilization. Long before human beings created the part of him lay infused in the oils on the canvas. When, painted for the sole purpose of transmitting thoughts.
written word they left their messages on the walls of as a practicing physician in New York, the still young Each communicates a vast amount of data, and uniquely
caves. Throughout history, art has been one form of Dr. Netter painted a memorable series of paintings stands alone, it needs no previous or subsequent paint-
capturing events in the education of a physician, the ings to support it. Yet each painting is a part of the
artist was still very much at work. The paintings indi- overall scheme conceived years ago to portray the total
vidually communicated joy, sadness, nostalgia, pathos, world of medical science, organ by organ, system by
and inspiration. There was added, though, another system.
dimension—realism—bold, factual, blunt realism.
Patients were very much patients and artistic license Not even Dr. Netter is capable of knowing all there
was not taken for the sake of emotional impact. is to know about the human body. Where once he relied
on personal reading and literature research as sources
Those paintings, a curious blend of great artistic sen- of knowledge for a painting, now the emphasis is
sitivity in a setting of stark clinical realism, document on direct contact with a recognized expert in a particu-
the true turning point in Frank Netter’s life. Previously, lar field. The consultant speaks, Netter listens, and
the artist Netter wrestled with the physician Netter for Netter becomes the extension of the mind of the con-
his time and talents. He had been the artist who had sultant. The process is repeated continuously. Through-
become the physician, the physician who had been part- out the world there exists a group of distinguished
time artist, but before that series of paintings never leaders in medicine and the biologic sciences who are
really both at once. the collaborators and consultants to Dr. Netter and the
CIBA COLLECTION. United by the common goals
During the next few pre-World War II years Frank of learning, teaching, and research, this geographically
Netter evolved into a new breed of man, unlike any scattered group has one additional bond of unity—its
before him, capable of portraying the clinical scene with association with Frank H. Netter, MD, the dean of a
the skill of the artist and the coolness of the surgeon. If university without walls, the teacher who listens.
important to the clinical setting, a patient’s emotional
reactions to illness and suffering would command Robert K. Shapter, MD, CM
the viewer’s attention, but the viewer would never be

viii THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

INTRODUCTION TO THE FIRST EDITION

It is now more than 25 years since I began preparing comprehension of nephron structure, organization, and hypertension, renin, angiotensin, aldosterone, other
the series of volumes entitled THE CIBA COLLEC- blood supply needed for better understanding of normal cortical hormones, pituitary hormones, parathyroid
TION OF MEDICAL ILLUSTRATIONS. As origi- and abnormal kidney function. function, inborn metabolic errors, immunologic factors,
nally conceived, the series was to depict, system by homeostasis, and water and electrolyte balance.
system, the anatomy, embryology, physiology, pathol- Technology had also progressed. For example, the
ogy, pathologic physiology, and pertinent clinical fea- electron microscope had not only greatly enlarged our The task with which I was faced was thus truly for-
tures of diseases of the entire human organism. As I knowledge of renal structure and pathology, but it had midable. Its accomplishment was only made possible by
progressed through the volumes, I continually post- also improved our visualization of the underlying pro- the gracious and devoted help of the many distinguished
poned the day when I would attempt to portray the cesses in many renal disorders. The whole field of dialy- collaborators and consultants who are credited indi-
kidneys and urinary tract. Since so much progress was sis had opened and kidney transplantation had become vidually on other pages of this volume. I wish to express
being made in the study of these organs and their dis- a practical reality. New renal function tests had been here my sincere appreciation for their help and for the
orders, I hoped that the discrepancies in our knowledge devised and new technics for urine examination devel- time which they gave me despite their busy schedules,
would be rectified, the inconsistencies in our theories oped. The field of renal radiology had greatly expanded as well as to express my admiration for their knowledge
clarified, and the differences in our interpretations and and radioactive scanning had been utilized as a valuable and wisdom. I especially thank Dr. E. Lovell “Stretch”
opinions resolved. Miraculously, through the persistent diagnostic tool. Becker and Dr. Jacob “Jack” Churg. They guided me
endeavors of many brilliant and devoted researchers, through this project, and their devotion to it was a
clinicians, and surgeons throughout the world, this took This incredible progress as well as the clinical aspects source of stimulation. The close cooperation of the
place. of the many renal and urinary tract disorders required editor, Dr. Robert K. Shapter, who took over in “mid-
illustration. In this volume, I have included a number stream” from Dr. Fredrick Yonkman, was most gratify-
Nevertheless, when the day came to begin this of illustrative flow charts depicting the common clinical ing. There were many others who lightened the burden
volume, I found that, because of the tremendous prog- course of renal diseases such as acute and chronic glo- of this endeavor in various ways, but foremost among
ress, my task had become not easier and simpler, but merulonephritis. In my efforts to portray the kidney, I these was Miss Louise Stemmle, production editor.
more difficult and involved. With each discovery, new found I could not consider either it or nephrology as
vistas of exploration had appeared, with each clarifica- an isolated study because kidney function is intimately Underlying the creation of this and the other volumes
tion, new avenues of investigation had opened. Indeed, related to function of other organ systems, and to of this series has been the vision, understanding, and
progress in clinical nephrology often necessitated bodily function in general. The circulatory, endocrine, unreserved backing of CIBA Pharmaceutical Company
reevaluation of formerly established concepts. Even and metabolic systems are particularly involved, and and its executives who have given me so free a hand in
renal anatomy, once thought of as a static subject, had progress in the study of these fields has meant progress this work.
been completely restudied to provide the more precise in nephrology. It was necessary to consider kidney func-
tion and kidney disease in relation to such topics as Frank H. Netter, MD

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS ix



We dedicate this book to our parents––
Robert and Anna Kelly

and Fevus and Klara Landman—
who inspired our dreams
of becoming physicians,

then gave us the resources, support,
and confidence to pursue them.

Robert and Anna Kelly

Fevus and Klara Landman

ADVISORY BOARD

James D. Brooks, MD Abhay Rané, MS, FRCS (Urol)

Associate Professor of Urology Consultant, Urological Surgeon
Stanford University School of Medicine East Surrey Hospital
Stanford, California Redhill, Surrey, United Kingdom

Marius Cloete Conradie, MB ChB, FC (Urol) Eduardo Cotecchia Ribeiro

Head of Department of Urology Associate Professor
Pietermaritzburg Metropolitan Morphology and Genetics Department
President of Southern African Endourology Society Federal University of São Paulo School of Medicine
Berea, KwaZulu-Natal, South Africa São Paulo, Brazil

Francis Xavier Keeley, Jr., MD, FRCS (Urol)

Consultant Urologist
Bristol Urological Institute
Bristol, United Kingdom

xii THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

CONTRIBUTORS

EDITORS-IN-CHIEF Jeffrey Newhouse, MD Sara L. Best, MD
Professor of Radiology and Urology Assistant Professor
Christopher R. Kelly, MD Director, Division of Abdominal Radiology Department of Urology
Postdoctoral Residency Fellow NewYork–Presbyterian Hospital University of Wisconsin School of Medicine and
Department of Medicine Columbia University Medical Center
NewYork–Presbyterian Hospital New York, New York Public Health
Columbia University Medical Center Plates 4-35, 9-1, 9-2 Madison, Wisconsin
New York, New York Plates 1-4, 1-12, 2-5, 2-9, 2-11, 2-14, 2-16–2-18, 2-25, Plates 6-3–6-5
Plates 1-18–1-27, 2-1–2-35, 3-1–3-24, 3-27, 3-28, 4-1,
2-27, 2-33, 5-8, 5-10, 5-12, 6-2, 6-5–6-7, 7-1–7-5, Nahid Bhadelia, MD, MS
4-2, 4-14, 4-15, 4-32–4-34, 4-36, 4-37, 4-61, 4-62, 9-1–9-3, 9-9, 9-12 (imaging) Assistant Professor of Medicine
6-1, 6-2, 6-7, 9-1–9-10, 10-1–10-6, 10-12, Section of Infectious Diseases
10-17–10-34, 10-36–10-40 Jai Radhakrishnan, MD, MS Department of Medicine
Associate Professor of Clinical Medicine Boston University School of Medicine
Jaime Landman, MD Division of Nephrology Boston, Massachusetts
Professor of Urology and Radiology Department of Medicine Plates 5-1–5-12
Chairman, Department of Urology NewYork–Presbyterian Hospital
University of California Irvine Columbia University Medical Center Andrew S. Bomback, MD, MPH
Irvine, California New York, New York Assistant Professor of Clinical Medicine
Plates 2-14, 2-19, 2-20, 6-1, 6-2, 6-7, 9-1–9-6, 9-9, Plates 4-1–4-15, 4-19–4-25, 4-28–4-31, 4-35, Division of Nephrology
Department of Medicine
9-10, 10-12, 10-17–10-25, 10-33, 10-34, 4-38–4-41, 4-45–4-54, 4-61, 4-62, 4-66–4-70, 10-7, NewYork–Presbyterian Hospital
10-36–10-40 10-8, 10-26–10-32 Columbia University Medical Center
New York, New York
SENIOR EDITORS ASSOCIATE EDITORS Plates 4-5–4-9, 4-12, 4-13

Arthur Dalley, PhD Adam C. Mues, MD Steven Brandes, MD
Professor, Cell & Developmental Biology Assistant Professor Professor of Surgery
Director, Structure, Function, and Development Department of Urology Director, Section of Reconstructive Urology
Vanderbilt University School of Medicine New York School of Medicine Division of Urologic Surgery
Nashville, Tennessee New York, New York Department of Surgery
Plates 1-1–1-17 Plates 2-14, 6-1, 6-2, 6-7, 9-1–9-6, 9-9, 9-10, 10-12, Washington University Medical Center
St. Louis, Missouri
Leal Herlitz, MD 10-17–10-25, 10-33, 10-34, 10-36–10-40 Plates 7-1–7-5
Assistant Professor of Clinical Pathology Plate 2-13 (imaging)
Division of Renal Pathology Amay Parikh, MD, MBA, MS
Department of Pathology and Cell Biology Instructor in Clinical Medicine Dennis Brown, MD, PhD
NewYork–Presbyterian Hospital Division of Nephrology Professor of Medicine, Harvard Medical School
Columbia University Medical Center Department of Medicine Director, MGH Program in Membrane Biology
New York, New York NewYork–Presbyterian Hospital MGH Center for Systems Biology and Division of
Plates 2-15, 2-16, 4-26, 4-27, 4-63, 10-26–10-32 Columbia University Medical Center
Plates 1-20, 4-9–4-11, 4-14, 4-15, 4-24, 4-25, 4-27, New York, New York Nephrology
Plates 4-40, 4-41, 10-9–10-11 Massachusetts General Hospital
4-31, 4-50–4-52, 4-54, 4-59, 4-63, 10-28, 10-30– Simches Research Center
10-32 (imaging) CONTRIBUTORS Boston, Massachusetts
Plate 1-26 (imaging)
Peter A. Humphrey, MD, PhD Gina M. Badalato, MD
Ladenson Professor of Pathology and Immunology Resident, Department of Urology Pietro Canetta, MD
Professor of Urologic Surgery NewYork–Presbyterian Hospital Assistant Professor of Clinical Medicine
Chief, Division of Anatomic and Molecular Pathology Columbia University Medical Center Division of Nephrology
Washington University School of Medicine New York, New York Department of Medicine
St. Louis, Missouri Plates 8-1–8-5 NewYork–Presbyterian Hospital
Plates 1-18–1-27, 9-1–9-6, 9-9–9-13 Columbia University Medical Center
Gerald Behr, MD New York, New York
Antoine Khoury, MD Assistant Professor of Clinical Radiology Plates 4-19–4-24, 4-49–4-52
Chief of Pediatric Urology Department of Radiology
Professor of Urology NewYork–Presbyterian Hospital Carmen R. Cobelo, MD
University of California, Irvine Columbia University Medical Center Nephrology Fellow
Irvine, California New York, New York Hospital Regional
Plates 2-21, 2-22, 2-26–2-29 Plate 9-7 (imaging) Universitario Carlos Haya
Plate 2-35 (imaging) Malaga, Spain
Mitchell C. Benson, MD Plates 4-8, 4-9
George F. Cahill Professor and Chairman
Department of Urology
NewYork–Presbyterian Hospital
Columbia University Medical Center
New York, New York
Plates 9-11–9-13

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS xiii

Kimberly L. Cooper, MD Joseph Graversen, MD Contributors
Assistant Professor Fellow, Minimally Invasive Urology
Co-Director of Voiding Dysfunction, Incontinence, Department of Urology James M. McKiernan, MD
University of California Irvine John and Irene Given Associate Professor of Urology
and Urodynamics Irvine, California Director, Urologic Oncology
NewYork–Presbyterian Hospital Plates 10-39, 10-40 Department of Urology
Columbia University Medical Center NewYork–Presbyterian Hospital
New York, New York Mohan Gundeti, MB MS, MCh Columbia University Medical Center
Plates 8-1–8-5 Associate Professor of Urology in Surgery and New York, New York
Plates 10-39, 10-40 (imaging)
Vivette D’Agati, MD Pediatrics
Professor of Pathology Director, Pediatric Urology Shannon Nees
Division of Renal Pathology Director, The Center for Pediatric Robotic and Doris Duke Clinical Research Fellow
Department of Pathology and Cell Biology Division of Pediatric Urology
NewYork–Presbyterian Hospital Minimal Invasive Surgery Department of Urology
Columbia University Medical Center University of Chicago, Comer Children’s Hospital Columbia University
New York, New York Chicago, Illinois College of Physicians and Surgeons
Plates 4-55–4-57 Plates 6-6, 10-16 New York, New York
Plates 2-30, 2-31, 2-34, 2-35
Alberto de Lorenzo, MD Mantu Gupta, MD
Nephrology Fellow Associate Professor Galina Nesterova, MD
Hospital Universitario de La Princesa Director, Endourology Staff Clinician
Universidad Autónoma de Madrid Director, Kidney Stone Center Section on Human Biochemical Genetics
Madrid, Spain Department of Urology Medical Genetics Branch
Plates 4-12, 4-13 NewYork–Presbyterian Hospital Intramural Program
Columbia University Medical Center Office of Rare Diseases
Gerald F. DiBona, MD New York, New York National Institutes of Health
Professor Plates 10-13–10-15 Bethesda, Maryland
Departments of Internal Medicine and Molecular Plates 4-64, 4-65
Fiona Karet, MB, BS, PhD
Physiology & Biophysics Professor of Nephrology Amudha Palanisamy, MD
University of Iowa Carver College of Medicine Department of Medicine Instructor in Clinical Medicine
Iowa City, Iowa University of Cambridge Division of Nephrology
Plates 1-14–1-16 Cambridge Institute for Medical Research NewYork–Presbyterian Hospital
Cambridge, United Kingdom Columbia University Medical Center
William A. Gahl, MD, PhD Plates 3-25, 3-26 New York, New York
Clinical Director, National Human Genome Research Plates 4-10, 4-11, 4-28, 4-29
Anna Kelly, MD
Institute Assistant Professor of Clinical Radiology Margaret S. Pearle, MD, PhD
Head, Section on Human Biomedical Genetics, NewYork–Presbyterian Hospital Professor of Urology and Internal Medicine
Columbia University Medical Center The University of Texas Southwestern Medical
Medical Genetics Branch New York, New York
Head, Intramural Program, Office of Rare Diseases Plate 2-16 (imaging) Center
National Institutes of Health Dallas, Texas
Bethesda, Maryland Cheryl Kunis, MD Plates 6-3–6-5
Plates 4-64, 4-65 Professor of Clinical Medicine
Division of Nephrology Allison R. Polland, MD
Anjali Ganda, MD, MS Department of Medicine Resident, Department of Urology
Instructor in Clinical Medicine NewYork–Presbyterian Hospital Mount Sinai Medical Center
Division of Nephrology Columbia University Medical Center New York, New York
Department of Medicine New York, New York Plate 10-12
NewYork–Presbyterian Hospital Plates 4-42–4-44, 4-58–4-60
Columbia University Medical Center Maya Rao, MD
New York, New York Michael Large, MD Assistant Professor of Clinical Medicine
Plates 4-38, 4-39 Fellow, Urologic Oncology Division of Nephrology
University of Chicago Hospitals Department of Medicine
James N. George, MD Chicago, Illinois NewYork–Presbyterian Hospital
George Lynn Cross Professor Plates 6-6, 10-16 Columbia University Medical Center
Departments of Medicine, Biostatistics & New York, New York
Mary McKee Plates 4-66–4-70
Epidemiology Senior Lab Technologist
University of Oklahoma Health Sciences Center MGH Program in Membrane Biology Lloyd Ratner, MD
Oklahoma City, Oklahoma MGH Center for Systems Biology and Division of Professor of Surgery
Plates 4-32–4-34 Director, Renal and Pancreatic Transplantation
Nephrology NewYork–Presbyterian Hospital
Mythili Ghanta, MBBS Boston, Massachusetts Columbia University Medical Center
Assistant Professor of Internal Medicine Plate 1-26 (imaging) New York, New York
Section of Nephrology Plates 10-26–10-32
Department of Internal Medicine
Wake Forest University School of Medicine
Winston-Salem, North Carolina
Plates 4-35, 4-47, 4-48

xiv THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Matthew Rutman, MD Magdalena E. Sobieszczyk, MD, MPH Contributors
Assistant Professor Assistant Professor of Clinical Medicine
Co-Director of Voiding Dysfunction, Incontinence, Division of Infectious Disease Matthew D. Truesdale, MD
Department of Medicine Resident, Department of Urology
and Urodynamics NewYork–Presbyterian Hospital University of California, San Francisco
Department of Urology Columbia University Medical Center San Francisco, California
NewYork–Presbyterian Hospital New York, New York Plates 9-3–9-6
Columbia University Medical Center Plates 5-1–5-12
New York, New York Duong Tu, MD
Plates 8-1–8-5 Michal Sobieszczyk, MD Fellow, Pediatric Urology
Resident, Internal Medicine Department Department of Urology
P. Roderigo Sandoval, MD Walter Reed National Military Medical Center Children’s Hospital Boston
Assistant Professor Bethesda, Maryland Harvard Medical School
Department of Surgery Plates 5-11, 5-12 Boston, Massachusetts
NewYork–Presbyterian Hospital Plates 2-19, 2-20, 2-23–2-29, 2-32, 2-33
Columbia University Medical Center David Sperling, MD
New York, New York Director, Columbia Endovascular Associates/ Anthony Valeri, MD
Plates 10-26–10-32 Associate Professor of Clinical Medicine
Interventional Radiology Director, Hemodialysis
Richard Schlussel, MD Department of Radiology NewYork–Presbyterian Hospital
Associate Director, Pediatric Urology NewYork–Presbyterian Hospital Columbia University Medical Center
Assistant Professor of Urology Columbia University Medical Center New York, New York
Columbia University New York, New York Plates 10-9–10-11
Morgan Stanley Children’s Hospital Plate 1-11 (imaging)
New York, New York Lt. Col. Kyle Weld, MD
Plate 10-35 M. Barry Stokes, MB, BCh Director of Endourology
Plates 2-22, 2-23 (imaging) Associate Professor of Clinical Pathology 59th Surgical Specialties Squadron
Division of Renal Pathology Plates 1-10–1-12
Arieh Shalhav, MD Department of Pathology and Cell Biology
Professor of Surgery NewYork–Presbyterian Hospital Sven Wenske, MD
Chief, Section of Urology Columbia University Medical Center Fellow, Department of Urology
Director, Minimally Invasive Urology New York, New York NewYork–Presbyterian Hospital
University of Chicago Medical Center Plates 4-16–4-18 Columbia University Medical Center
Chicago, Illinois Plates 1-23, 1-25, 4-4, 4-13, 4-20, 4-21, 4-29, 4-43, New York, New York
Plates 6-6, 10-16 Plates 2-1–2-13, 2-18, 9-7, 9-8, 10-35
4-44, 4-46, 4-48, 4-63 (imaging)
Shayan Shirazian, MD Frances V. White, MD
Assistant Professor of Clinical Medicine Stephen Textor, MD Associate Professor
Department of Medicine Professor of Medicine Department of Pathology and Immunology
State University of New York at Stony Brook Division of Nephrology and Hypertension Washington University Medical Center
Attending Nephrologist Mayo Clinic St. Louis, Missouri
Winthrop University Hospital Rochester, Minnesota Plate 9-8 (imaging)
Mineola, New York Plates 4-36, 4-37
Plates 4-3, 4-4, 4-14, 4-15, 4-30, 4-31 Matthew Wosnitzer, MD
Sandhya Thomas, MD Chief Resident, Department of Urology
Eric Siddall, MD Fellow, Division of Nephrology NewYork–Presbyterian Hospital
Fellow, Division of Nephrology Department of Medicine Columbia University Medical Center
Department of Medicine Baylor College of Medicine New York, New York
NewYork–Presbyterian Hospital Houston, Texas Plates 9-11–9-13
Columbia University Medical Center Plates 4-45, 4-46, 4-61, 4-62, 10-7, 10-8
New York, New York
Plates 4-25, 4-53, 4-54

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS xv



CONTENTS

SECTION 1 2-17 Medullary Sponge Kidney, 46 3-20 Acid-Base Balance: Roles of Chemical
2-18 Nephronophthisis/Medullary Cystic Kidney Buffers, Lungs, and Kidneys in Acid-Base
ANATOMY OF THE URINARY TRACT Handling, 86
Disease Complex, 47
1-1 Kidney: Position and Relations 2-19 Retrocaval Ureter: Radiographic Findings 3-21 Acid-Base Balance: Renal Bicarbonate
(Anterior View), 2 Reabsorption, 87
and Laparoscopic Repair, 48
1-2 Kidney: Position and Relations 2-20 Retrocaval Ureter: Normal Development of 3-22 Acid-Base Balance: Renal Bicarbonate
(Posterior View), 3 Synthesis and Proton Excretion, 88
the Inferior Vena Cava, 49
1-3 Kidney: Position and Relations 2-21 Vesicoureteral Reflux: Mechanism and 3-23 Acid-Base Balance: Acidosis and
(Transverse Sections), 4 Alkalosis, 89
Grading, 50
1-4 Kidney: Gross Structure, 5 2-22 Vesicoureteral Reflux: Voiding 3-24 Additional Functions: Erythropoiesis and
1-5 Renal Fascia, 6 Vitamin D, 90
1-6 Ureters: Position, Relations, Gross Cystourethrograms, 51
2-23 Ureteral Duplication: Complete, 52 3-25 Proximal Renal Tubular Acidosis, 91
Structure, 7 2-24 Ureteral Duplication: Incomplete, 53 3-26 Classic Distal Renal Tubular Acidosis, 92
1-7 Bladder: Position, Relations, Gross 2-25 Ectopic Ureter, 54 3-27 Nephrogenic Diabetes Insipidus: Diabetes
2-26 Ureterocele: Gross and Fine
Structure (Male), 8 Insipidus, 93
1-8 Bladder: Position, Relations, Gross Appearance, 55 3-28 Major Causes and Symptoms of
2-27 Ureterocele: Radiographic Findings, 56
Structure (Female), 9 2-28 Prune Belly Syndrome: Appearance of Nephrogenic Diabetes Insipidus, 94
1-9 Bladder: Position, Relations, Gross
Abdominal Wall, 57 SECTION 4
Structure (Coronal Cross-Section), 10 2-29 Prune Belly Syndrome: Appearance of
1-10 Renal Vasculature: Renal Artery and Vein RENAL DISEASES
Kidneys, Ureters, and Bladder, 58
In Situ, 11 2-30 Epispadias Exstrophy Complex: 4-1 Overview of Acute Kidney Injury:
1-11 Renal Vasculature: Renal Artery Segmental Causes, 96
Epispadias, 59
Branches and Intrarenal Arteries, 12 2-31 Epispadias Exstrophy Complex: Bladder 4-2 Overview of Acute Kidney Injury: Possible
1-12 Renal Vasculature: Variations in Renal Urine Sediment Findings, 97
Exstrophy, 60
Artery and Vein, 13 2-32 Bladder Duplication and Septation, 61 4-3 Acute Tubular Necrosis: Causes,
1-13 Vasculature of Ureters and Bladder, 14 2-33 Anomalies of the Urachus, 62 Pathophysiology, and Clinical
1-14 Innervation of Kidneys, Ureters, and 2-34 Posterior Urethral Valves: Gross Features, 98

Bladder, 15 Appearance, 63 4-4 Acute Tubular Necrosis: Histopathologic
1-15 Innervation Pathways of the Kidneys and 2-35 Posterior Urethral Valves: Radiographic Findings, 99

Upper Ureter, 16 Findings, 64 4-5 Overview of Nephrotic Syndrome:
1-16 Innervation Pathways of the Ureter and Pathophysiology, 100
SECTION 3
Bladder, 17 4-6 Overview of Nephrotic Syndrome:
1-17 Lymphatics of Urinary System, 18 PHYSIOLOGY Causes, 101
1-18 Overview of the Nephron, 19
1-19 Renal Microvasculature, 20 3-1 Basic Functions and Homeostasis, 67 4-7 Overview of Nephrotic Syndrome:
1-20 Glomerulus: Structure and Histology, 21 3-2 Clearance and Renal Plasma Flow, 68 Presentation and Diagnosis, 102
1-21 Glomerulus Fine Structure, 22 3-3 Glomerular Filtration Rate, 69
1-22 Glomerulus: Electron Microscopy, 23 3-4 Glomerular Filtration Rate: 4-8 Minimal Change Disease: Causes and
1-23 Proximal Tubule, 24 Presentation, 103
1-24 Thin Limb, 25 Calculation, 70
1-25 Distal Tubule, 26 3-5 Secretion and Reabsorption: Tubular 4-9 Minimal Change Disease: Histopathologic
1-26 Collecting Duct, 27 Findings, 104
1-27 Renal Pelvis, Ureter, and Bladder, 28 Reabsorption and Saturation Kinetics, 71
3-6 Secretion and Reabsorption: Fractional 4-10 Focal Segmental Glomerulosclerosis:
SECTION 2 Causes, Clinical Features, and
Excretion (Clearance Ratios), 72 Histopathologic Findings, 105
NORMAL AND ABNORMAL 3-7 Renal Handling of Sodium and
DEVELOPMENT 4-11 Focal Segmental Glomerulosclerosis:
Chloride: Nephron Sites of Sodium Histopathologic Findings (Continued), 106
2-1 Development of Kidney, 30 Reabsorption, 73
2-2 Development of Kidney: Nephron 3-8 Renal Handling of Sodium and Chloride: 4-12 Membranous Nephropathy: Causes and
Response to Extracellular Fluid Clinical Features, 107
Formation, 31 Contraction, 74
2-3 Development of Bladder and Ureter: 3-9 Renal Handling of Sodium and 4-13 Membranous Nephropathy:
Chloride: Response to Extracellular Fluid Histopathologic Findings, 108
Formation of the Cloaca, 32 Expansion, 75
2-4 Development of Bladder and Ureter: 3-10 Renal Handling of Potassium, 76 4-14 Overview of Glomerulonephritis:
3-11 Renal Handling of Calcium, Phosphate, Clinical Features and Histopathologic
Septation, Incorporation of Ureters, and and Magnesium, 77 Findings, 109
Maturation, 33 3-12 Countercurrent Multiplication: Model—Part
2-5 Renal Ascent and Ectopia: Normal Renal I, 78 4-15 Overview of Glomerulonephritis:
Ascent and Pelvic Kidney, 34 3-13 Countercurrent Multiplication: Model—Part Histopathologic Findings (Continued), 110
2-6 Renal Ascent and Ectopia: Thoracic and II, 79
Crossed Ectopic Kidney, 35 3-14 Countercurrent Multiplication: Models to 4-16 IgA Nephropathy: Causes and Clinical
2-7 Renal Rotation and Malrotation, 36 Demonstrate Principle of Countercurrent Features, 111
2-8 Anomalies in Number of Kidneys: Bilateral Exchange System of Vasa Recta in
Renal Agenesis, 37 Minimizing Dissipation of Medullary 4-17 IgA Nephropathy: Histopathologic
2-9 Anomalies in Number of Kidneys: Osmotic Gradient, 80 Findings, 112
Unilateral Renal Agenesis, 38 3-15 Urine Concentration and Dilution and
2-10 Anomalies in Number of Kidneys: Overview of Water Handling: Long-Looped 4-18 IgA Nephropathy: Histopathologic
Supernumerary Kidney, 39 Nephron (ADH Present), 81 Findings (Continued), 113
2-11 Renal Fusion, 40 3-16 Urine Concentration and Dilution: Long-
2-12 Renal Dysplasia, 41 Looped Nephron (ADH Absent), 82 4-19 Postinfectious Glomerulonephritis: Causes
2-13 Renal Hypoplasia, 42 3-17 Antidiuretic Hormone, 83 and Clinical Features, 114
2-14 Simple Cysts, 43 3-18 Tubuloglomerular Feedback and
2-15 Polycystic Kidney Disease: Gross Modulation of Renin Release, 84 4-20 Postinfectious Glomerulonephritis:
Appearance, 44 3-19 Tubuloglomerular Feedback and Renin- Histopathologic Findings, 115
2-16 Polycystic Kidney Disease: Radiographic Angiotensin-Aldosterone System, 85
Findings, 45 4-21 Postinfectious Glomerulonephritis:
Histopathologic Findings (Continued), 116

4-22 Membranoproliferative
Glomerulonephritis: Causes, Features, and
Assessment, 117

4-23 Membranoproliferative
Glomerulonephritis: Classical Pathway of
Complement Activation, 118

4-24 Membranoproliferative
Glomerulonephritis: Histopathologic
Findings, 119

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS xvii

Contents

4-25 Rapidly Progressive 4-65 Cystinosis: Extrarenal 8-5 Urodynamics: Sample Urodynamic
Glomerulonephritis, 120 Manifestations, 160 Recordings, 200

4-26 Hereditary Nephritis (Alport Syndrome)/ 4-66 Overview of Chronic Kidney Disease: SECTION 9
Thin Basement Membrane Staging System and Major Causes, 161
Nephropathy: Pathophysiology and NEOPLASMS
Clinical Features, 121 4-67 Overview of Chronic Kidney Disease:
Normal Calcium and Phosphate 9-1 Benign Renal Tumors: Papillary Adenoma
4-27 Hereditary Nephritis (Alport Syndrome)/ Metabolism, 162 and Oncocytoma, 202
Thin Basement Membrane Nephropathy:
Electron Microscopy Findings, 122 4-68 Overview of Chronic Kidney Disease: 9-2 Benign Renal Tumors:
Calcium and Phosphate Metabolism in Angiomyolipoma, 203
4-28 Acute Interstitial Nephritis: Causes and Chronic Kidney Disease, 163
Clinical Features, 123 9-3 Renal Cell Carcinoma: Risk Factors and
4-69 Overview of Chronic Kidney Disease: Radiographic Findings, 204
4-29 Acute Interstitial Nephritis: Mechanism of Progression and
Histopathologic Findings, 124 Complications, 164 9-4 Renal Cell Carcinoma: Gross Pathologic
Findings, 205
4-30 Chronic Tubulointerstitial Nephritis and 4-70 Overview of Chronic Kidney Disease:
Analgesic Nephropathy, 125 Uremia, 165 9-5 Renal Cell Carcinoma: Histopathologic
Findings, 206
4-31 Chronic Tubulointerstitial Nephritis: SECTION 5
Histopathologic Findings, 126 9-6 Renal Cell Carcinoma: Staging System and
URINARY TRACT INFECTIONS Sites of Metastasis, 207
4-32 Thrombotic Microangiopathy: General
Features, 127 5-1 Cystitis: Risk Factors, 168 9-7 Wilms Tumor: Genetics, Presentation, and
5-2 Cystitis: Common Symptoms and Radiographic Findings, 208
4-33 Thrombotic Microangiopathy: Hemolytic
Uremic Syndrome, 128 Tests, 169 9-8 Wilms Tumor: Gross Appearance and
5-3 Cystitis: Evaluation, 170 Histopathologic Findings, 209
4-34 Thrombotic Microangiopathy: Thrombotic 5-4 Cystitis: Treatment, 171
Thrombocytopenic Purpura, 129 5-5 Pyelonephritis: Risk Factors and Major 9-9 Tumors of the Renal Pelvis and Ureter:
Risk Factors and Radiographic
4-35 Renal Vein Thrombosis, 130 Findings, 172 Appearance, 210
4-36 Renal Artery Stenosis: Pathophysiology of 5-6 Pyelonephritis: Pathology, 173
5-7 Bacteriuria: Management of 9-10 Tumors of the Renal Pelvis and Ureter:
Renovascular Hypertension, 131 Appearance (Ureteroscopic, Gross, and
4-37 Renal Artery Stenosis: Causes, 132 Asymptomatic Bacteriuria, 174 Microscopic) and Staging System, 211
4-38 Congestive Heart Failure: Types of Left 5-8 Intrarenal and Perinephric
9-11 Tumors of the Bladder: Risk Factors,
Heart Failure and Effects on Renal Abscesses, 175 Symptoms, and Physical Examination, 212
Function, 133 5-9 Tuberculosis: Infection and
4-39 Congestive Heart Failure: Effects of Left 9-12 Tumors of the Bladder: Cystoscopic and
Heart Failure on Renal Blood Flow and Extrapulmonary Spread, 176 Radiographic Appearance, 213
Tubular Function, 134 5-10 Tuberculosis: Urinary Tract, 177
4-40 Hepatorenal Syndrome: Proposed 5-11 Schistosomiasis: Life Cycle of 9-13 Tumors of the Bladder: Histopathologic
Pathophysiology, 135 Findings and Staging System, 214
4-41 Hepatorenal Syndrome: Symptoms and Schistosoma Haematobium, 178
Diagnosis, 136 5-12 Schistosomiasis: Effects of Chronic SECTION 10
4-42 Chronic and Malignant Hypertension:
Major Causes, 137 Schistosoma Haematobium THERAPEUTICS
4-43 Chronic and Malignant Hypertension: Infection, 179
Renal Histopathology (Chronic), 138 10-1 Osmotic Diuretics, 216
4-44 Chronic and Malignant Hypertension: SECTION 6 10-2 Carbonic Anhydrase Inhibitors, 217
Renal Histopathology (Malignant), 139 10-3 Loop Diuretics, 218
4-45 Diabetic Nephropathy: Diabetes URINARY TRACT OBSTRUCTIONS 10-4 Thiazide Diuretics, 219
Mellitus, 140 10-5 Potassium-Sparing Diuretics, 220
4-46 Diabetic Nephropathy, 141 6-1 Obstructive Uropathy: Etiology, 182 10-6 Inhibitors of the Renin-Angiotensin
4-47 Amyloidosis: Deposition Sites and 6-2 Obstructive Uropathy: Sequelae, 183
Manifestations, 142 6-3 Urolithiasis: Formation of Renal System, 221
4-48 Amyloidosis: Histopathologic 10-7 Renal Biopsy: Indications and Structure of
Findings, 143 Stones, 184
4-49 Lupus Nephritis: Diagnostic Criteria, 144 6-4 Urolithiasis: Major Sites of Renal Stone Typical Spring-Loaded Needle, 222
4-50 Lupus Nephritis: Renal Histopathology 10-8 Renal Biopsy: Procedure, 223
(Classes I and II Lesions), 145 Impaction, 185 10-9 Hemodialysis, Peritoneal Dialysis, and
4-51 Lupus Nephritis: Renal Histopathology 6-5 Urolithiasis: Appearance of Renal
(Classes III and IV Lesions), 146 Continuous Therapies: Hemodialysis, 224
4-52 Lupus Nephritis: Renal Histopathology Stones, 186 10-10 Hemodialysis, Peritoneal Dialysis, and
(Class V Lesions), 147 6-6 Ureteropelvic Junction Obstruction, 187
4-53 Myeloma Nephropathy: Pathophysiology 6-7 Ureteral Strictures, 188 Continuous Therapies: Vascular Access for
and Clinical Findings, 148 Hemodialysis, 225
4-54 Myeloma Nephropathy: Histopathologic SECTION 7 10-11 Hemodialysis, Peritoneal Dialysis, and
Findings, 149 Continuous Therapies: Peritoneal
4-55 HIV-Associated Nephropathy: Light TRAUMATIC INJURIES Dialysis, 226
Microscopy Findings, 150 10-12 Extracorporeal Shock Wave Lithotripsy, 227
4-56 HIV-Associated Nephropathy: Electron 7-1 Renal Injuries: Grading System and Renal 10-13 Percutaneous Nephrolithotomy: Creation
Microscopy Findings, 151 Parenchymal Injuries, 190 of Access Tract, 228
4-57 HIV-Associated Nephropathy: Mechanisms 10-14 Percutaneous Nephrolithotomy:
of Infection and Antiretroviral 7-2 Renal Injuries: Renal Hilar Injuries, 191 Nephroscope and Sonotrode, 229
Therapy, 152 7-3 Ureteral Injuries, 192 10-15 Percutaneous Nephrolithotomy: Ultrasonic
4-58 Preeclampsia: Clinical Definition and 7-4 Bladder Injuries: Extraperitoneal Bladder Lithotripsy of Large Stones, 230
Potential Mechanism of Pathogenesis, 153 10-16 Pyeloplasty and Endopyelotomy, 231
4-59 Preeclampsia: Renal Pathology, 154 Ruptures, 193 10-17 Renal Revascularization: Endovascular
4-60 Preeclampsia: HELLP Syndrome and 7-5 Bladder Injuries: Intraperitoneal Bladder Therapies, 232
Eclampsia, 155 10-18 Renal Revascularization: Surgical
4-61 Henoch-Schönlein Purpura: Diagnostic Ruptures, 194 Therapies, 233
Criteria, 156 10-19 Simple and Radical Nephrectomy: Open
4-62 Henoch-Schönlein Purpura: Additional SECTION 8 Nephrectomy (Incisions for
Clinical Features, 157 Transperitoneal and Retroperitoneal
4-63 Fabry Disease, 158 VOIDING DYSFUNCTION Approaches), 234
4-64 Cystinosis: Pathophysiology and the Renal 10-20 Simple and Radical Nephrectomy:
Fanconi Syndrome, 159 8-1 Voiding Dysfunction: Anatomy Open Simple Nephrectomy (Flank
of Female Urinary Continence Approach), 235
Mechanisms, 196 10-21 Simple and Radical Nephrectomy:
Laparoscopic Radical Nephrectomy
8-2 Voiding Dysfunction: Neural Control (Transperitoneal Approach
of Bladder Function and Effects of [Left-Sided]), 236
Pathologic Lesions, 197

8-3 Voiding Dysfunction: Stress Urinary
Incontinence, 198

8-4 Urodynamics: Equipment and Set-up for
Urodynamic Studies, 199

xviii THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Contents

10-22 Partial Nephrectomy: Open Partial 10-28 Renal Transplantation: Causes of Graft 10-34 Ureteroscopy: Stone Fragmentation and
Nephrectomy (Retroperitoneal [Flank] Dysfunction in Immediate Post-Transplant Extraction, 249
Approach), 237 Period, 243
10-35 Ureteral Reimplantation, 250
10-23 Partial Nephrectomy: Laparoscopic 10-29 Renal Transplantation: Causes of Graft 10-36 Ureteral Reconstruction, 251
Partial Nephrectomy (Transperitoneal Dysfunction in Early Post-Transplant 10-37 Cystoscopy: Cystoscope Design, 252
Approach), 238 Period, 244 10-38 Cystoscopy: Cystoscopic Views, 253
10-39 Transurethral Resection of Bladder Tumor:
10-24 Renal Ablation: Laparoscopic 10-30 Renal Transplantation: Acute Rejection
Cryoablation (Retroperitoneal (Pathologic Findings), 245 Equipment and Procedure, 254
Approach), 239 10-40 Transurethral Resection of Bladder Tumor:
10-31 Renal Transplantation: Calcineurin
10-25 Renal Ablation: Percutaneous Inhibitor Nephrotoxicity (Histopathologic Procedure (Continued), 255
Cryoablation, 240 Findings), 246
SELECTED REFERENCES, 257
10-26 Renal Transplantation: Recipient 10-32 Renal Transplantation: Causes of Graft
Operation, 241 Dysfunction in Late Post-Transplant INDEX, 261
Period, 247
10-27 Renal Transplantation: Mechanism of
Action of Immunosuppressive 10-33 Ureteroscopy: Device Design and
Medications, 242 Deployment, 248

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS xix



SECTION 1

ANATOMY OF THE
URINARY TRACT

Plate 1-1 Urinary System: VOLUME 5

POSITION AND RELATIONS OF KIDNEY: ANTERIOR VIEWS

Diaphragm Esophagus (cut)

Right suprarenal Left suprarenal gland
gland
Celiac trunk (cut)
Right kidney
Left kidney
Right renal
artery and vein Left renal artery
and vein
Right subcostal nerve
Superior mesenteric
Transversus artery (cut)
abdominis muscle
and aponeurosis Left subcostal nerve

Quadratus Abdominal aorta
lumborum muscle
Left iliohypogastric
Iliac crest nerve

Psoas major muscle Left ilioinguinal
nerve
Iliacus muscle
Left lateral femoral
Right ureter cutaneous nerve

Right common Left genitofemoral
iliac artery nerve

Right external Left testicular
iliac artery (ovarian) artery
and vein
Right internal
iliac artery Inferior mesenteric
artery (cut)
Urinary bladder
Peritoneum (cut)

Sigmoid mesocolon
(cut)

Rectum (cut)

Coronary ligament of liver Inferior vena cava Anterior relations
Right suprarenal gland Esophagus of kidneys
Area for bare area of liver
Gastrophrenic ligament
KIDNEY: POSITION AND
RELATIONS Left suprarenal gland

Splenorenal ligament

POSITION AND SHAPE Peritoneum (cut) Area for stomach

The kidneys are paired retroperitoneal organs that lie Area for liver Area for spleen
lateral to the upper lumbar vertebrae. In the relaxed,
supine position, their superior poles are level with the Duodenum Tail of pancreas
twelfth thoracic vertebra, while their inferior poles are
level with the third lumbar vertebra and about 2.5 cm Peritoneum (cut) Transverse mesocolon
superior to the iliac crest. On deep inspiration in the
erect position, however, both kidneys may descend near Area for colon Area for descending colon
or even past the iliac crest. Usually the right kidney lies
1 to 2 cm inferior to the left kidney because its devel- Area for small intestine Area for small intestine
opmental ascent is blocked by the liver.
rotated so that their medial surfaces are slightly by a variable amount of fat. The crescentic left supra-
Most commonly, both kidneys are surrounded by a anterior, facilitating their connection to these major renal gland lies medial to the upper third of the kidney,
variable amount of retroperitoneal fat (see Plate 1-5); vessels. extending from the apex to the hilum. The pyramidal
as in most anatomic descriptions, however, this fat is right suprarenal gland sits caplike on the superior pole
not considered in the relational descriptions that follow. The suprarenal glands, historically referred to as of the right kidney.
“adrenal” (a misnomer that incorrectly implied a sub-
Both kidneys lie in close proximity to the abdominal servient relationship to the kidneys), are bilateral glands The anterior relations of the left and right kidneys
aorta and inferior vena cava. These major vessels extend typically related to the superomedial aspects of the differ, reflecting their associations with the various
branches to each kidney that enter at a notched, medi- kidneys but not attached to them. They are attached to unpaired organs that constitute the abdominal viscera.
ally located area of the parenchyma known as the hilum. the diaphragmatic crura, a relationship maintained The posterior relations of both kidneys are similar,
At the level of the kidneys, the abdominal aorta lies in the presence of nephroptosis (“dropped kidneys”). reflecting their associations with the paired muscles of
directly anterior to the vertebral column, passing about Like the kidneys, the suprarenal glands are surrounded the posterior abdominal wall.
2.5 cm anteromedial to the left kidney. The inferior
vena cava lies to the right of the aorta, nearly touching
the medial aspect of the right kidney. Both kidneys are

2 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-2 Anatomy of the Urinary Tract

Latissimus POSITION AND RELATIONS OF KIDNEY: POSTERIOR VIEWS Pleura (costo-
dorsi muscle diaphragmatic
10 recess)
Serratus posterior 11
inferior muscle 12 Lumbocostal
ligament
External oblique
muscle Quadratus
lumborum
Aponeurosis of muscle (cut)
transversus
abdominis muscle Diaphragm

Internal oblique Right subcostal
muscle nerve

Thoracolumbar Right kidney
fascia (posterior
layer) Ascending colon

Iliac crest Transversus
abdominis muscle
Erector spinae
muscle Right iIiohypo-
gastric nerve
Gluteal aponeurosis
(over gluteus Right ilioinguinal
medius muscle) nerve

Gluteus maximus Quadratus
muscle lumborum
muscle (cut)

Psoas major muscle

Iliolumbar ligament

Aorta Inferior vena cava Posterior relations
of kidneys
Projection
KIDNEY: POSITION AND of 11th rib Area for diaphragm
RELATIONS (Continued)
Area for diaphragm Projection
ANTERIOR RELATIONS of 12th rib
Projection
Kidney development occurs in the retroperitoneal of 12th rib Area for
space on each side of a dorsal mesentery, which is ini- aponeurosis
tially attached along the midline of the posterior body Area for of transversus
wall. During growth of the liver and rotation of the gut, aponeurosis abdominis muscle
certain portions of the gut fuse to the posterior body of transversus
wall and become secondarily retroperitoneal. Through- abdominis
out this process, peritoneal reflections are shifted from muscle
the midline and distorted in an irregular but predictable
pattern. Area for quadratus Area for psoas major muscle Area for quadratus
lumborum muscle lumborum muscle
After development is complete, certain parts of
the kidneys contact intraperitoneal organs through Area for psoas major muscle
an intervening layer of peritoneum, whereas other
parts contact primarily or secondarily retroperitoneal splenic and gastric areas of the anterior renal surface mesocolon, a horizontally disposed derivative of the
organs without an intervening layer of peritoneum. are separated by the splenorenal ligament, a derivative embryonic dorsal mesentery that suspends the trans-
The presence or absence of intervening peritoneum of the dorsal mesentery that forms the left boundary of verse colon from the secondarily retroperitoneal viscera
may affect the spread of infection or metastatic the lesser sac. The two layers of the peritoneum that (i.e., duodenum and pancreas).
disease. form the splenorenal ligament enclose the splenic
vessels. The inferolateral aspect of the left kidney contacts
Left Kidney. The superolateral aspect of the left the descending colon, which is secondarily retro-
kidney contacts the spleen. Separating these organs is The perihilar region of the left kidney contacts the peritoneal, without intervening peritoneum. The infer-
the peritoneum that forms the posterior surface of the tail of the pancreas, a secondary retroperitoneal organ, omedial aspect of the left kidney contacts loops of
perisplenic region of the greater peritoneal sac. A without intervening peritoneum. This point of contact jejunum through an intervening layer of inframesocolic
triangular area on the superomedial aspect of the left occurs posterior to the left extremity of the transverse peritoneum.
kidney contacts the stomach. Separating these organs is
the peritoneum of the lesser sac (omental bursa). The

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 3

Plate 1-3 Urinary System: VOLUME 5
POSITION AND RELATIONS OF KIDNEY: TRANSVERSE SECTIONS

Level of T12–L1 intervertebral disc T12–L1
L1–2

Superior mesenteric vein (becoming portal vein) Transverse colon

Transverse colon Splenic vein

Pancreas (head) Jejunum

Ascending colon External oblique
(right colic flexure) muscle

(Common) bile duct Celiac trunk

Descending (2nd) Descending
part of duodenum colon

Inferior vena cava Left suprarenal
gland
Right supra-
renal gland Abdominal aorta

Liver Spleen

Superior pole Renal cortex Left kidney
of right kidney Renal medulla

Right crus
of diaphragm

T12–L1 inter-
vertebral disc

Left crus of diaphragm

KIDNEY: POSITION AND Level of L1–2 intervertebral disc Transverse colon
RELATIONS (Continued) Greater omentum
Superior mesenteric artery
Superior mesenteric vein
Pancreas with uncinate process Ileum
Transverse colon
Jejunum
Junction of 2nd and 3rd
parts of duodenum Perinephric fat

Right Kidney. The upper two thirds of the right Ascending colon Ureteropelvic
kidney contact the right lobe of the liver. The superior Inferior vena cava junction
pole extends above the coronary ligament to directly Liver
contact the bare area of the liver without intervening Descending
peritoneum. Inferior to the pole, the kidney is covered Right renal vein colon
with peritoneum that forms the posterior wall of the
hepatorenal recess (also known as the Morison pouch), Right kidney Renal fascia
part of the subhepatic space of the greater peritoneal Right crus
sac. of diaphragm Left kidney

The perihilar region of the right kidney directly con- Abdominal aorta Major calyx
tacts the second (descending) part of the duodenum, Psoas major muscle and renal pelvis
which is secondarily retroperitoneal. L1–2 intervertebral disc
Conus medullaris and cauda equina Paranephric fat
Most of the lower third of the right kidney is in direct
contact with the right colic flexure; however, a small Left renal artery
section of the inferior pole may contact the small intes-
tine through a layer of inframesocolic peritoneum. Left renal vein (entering
inferior vena cava)

Left crus of diaphragm

POSTERIOR RELATIONS ribs. A smaller portion of the right kidney receives left kidney, it is generally displaced farther from the
similar protection in its relationship to right twelfth rib. midline.
The approximate upper third of both kidneys contacts
the diaphragm. The diaphragm normally separates the With regard to the lower two thirds of both kidneys, On each side, two or three nerves pass posterior to
kidneys from the diaphragmatic part of the parietal the lateral aspects rest on the aponeuroses of the trans- the psoas muscle, emerge from its lateral border, then
pleura. On occasion, however, a deficiency in the region versus abdominis muscles; the central aspects rest on travel between the kidneys and the aponeurosis of the
of the lateral arcuate ligament or the lumbocostal the quadratus lumborum muscles; and the medial transverse abdominis as they descend obliquely to the
trigone allows one of the kidneys to directly contact the aspects rest on the psoas muscles. inguinal region. In craniocaudal order, these are the
overlying diaphragmatic pleura. subcostal (T12 spinal) nerve and the L1 spinal nerve or
The psoas muscles take an oblique course from the its terminal branches—the iliohypogastric and the ilio-
The upper third of the left kidney lies anterior to, lumbar vertebrae to the femurs, displacing the kidneys inguinal nerves.
and is thus protected by, the eleventh and twelfth left laterally. Because the right kidney lies inferior to the

4 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-4 Anatomy of the Urinary Tract

Anterior surface of right kidney
Superior pole

Fibrous (true) Cortex
capsule (cut
and peeled back) Medulla
Renal
Medial border (cortical)
column
Lateral border

Hilum

Renal artery

Renal vein

Renal pelvis

Stellate veins Computed tomography of left kidney
visible through with contrast in the cortical phase
capsule

Ureter

Inferior pole

Lobulated kidney Renal
of an infant with pelvis
suprarenal gland
Renal
KIDNEY: GROSS STRUCTURE (medul-
lary)
pyramids

The adult kidney is about 11 cm long, 2.5 cm thick, Right kidney sectioned in several planes, Computed tomography of right kidney
5 cm wide, and weighs between 120 and 170 g. The exposing parenchyma and renal pelvis with contrast in the excretory phase
lateral border of each kidney is convex, whereas the
medial border is concave. The superior and inferior Cortex Minor calices
poles are rounded. Both the anterior and posterior sur-
faces of the kidney are also convex, although the poste- Medulla
rior surface may be relatively flattened. (pyramids)

The renal artery and vein, as well as the urine col- Fibrous capsule
lecting system, enter and exit the medial aspect of each
kidney at the hilum. This indented region leads to a Minor calices
spacious cavity within each kidney known as the renal
sinus. Within the renal sinus, a matrix of perinephric Renal sinus Major
fat surrounds branches of the renal artery and vein, as calices
well as the large branches of the urinary collecting Renal papilla
system. The veins are generally the most anterior and Renal
the branches of the collecting system most posterior, Major calices pelvis
with the arteries coursing in between.
Renal pelvis Ureter
The entire outer rim of the renal parenchyma con-
sists of a brownish pink region known as the renal Renal (cortical)
cortex. Deep to the cortex, numerous darker-colored column
renal pyramids, with bases directed peripherally and
apices directed centrally, collectively form the renal Perinephric fat
medulla. The apices of the renal pyramids are known in renal sinus
as the renal papillae. Two or more pyramids may fuse
at their papillae; thus there are more pyramids than Minor calices Retrograde pyelogram of the right
papillae in each kidney. Base of kidney
pyramid
The areas of cortex overlying the bases of the pyra-
mids, separating them from the outer surface of the Ureter
kidney, are known as cortical arches. The areas of cortex
projecting between pyramids are known as renal (corti- These striations largely represent collecting ducts (see leaving the hilum. The ureter, in turn, conveys urine to
cal) columns (of Bertin). The term “column” refers to Plate 1-26), which extend from the cortex to the renal the bladder for storage.
their appearance on section; in fact, they are more like papillae, merging along the way into papillary ducts.
walls, which surround and separate the pyramids. The papillary ducts drain urine to 20 or more small The parenchyma served by a single papilla is known
pores at each papilla’s cribriform area (area cribrosa). as a renal lobe, and in the fetus and infant these lobes
Although the borders between pyramids and renal One to three papillae drain into each minor calyx; two are evident as grossly visible convexities separated by
columns are sharply defined, the pyramids project stria- to four minor calices join to form a major calyx; and deep grooves on the kidney surface. Such lobulation
tions into the cortical arches, known as medullary rays. two or three major calices join to form the funnel- persists in some mammalian species throughout life,
shaped renal pelvis, which becomes the ureter after and vestigial demarcations of lobulation are occasion-
ally present in the human adult.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 5

Plate 1-5 Urinary System: VOLUME 5

Transverse section through 2nd lumbar vertebra demonstrating horizontal disposition of renal fascia

Abdominal aorta Duodenojejunal flexure
Superior mesenteric vein and artery
Left renal vein and artery
Inferior vena cava
Duodenum Left kidney
Right kidney Peritoneum
Right colic (hepatic) flexure Descending
Liver colon

Transversalis
fascia

RENAL FASCIA Quadratus lumborum muscle Crura of diaphragm Paranephric fat
Psoas major muscle and fascia Perinephric fat
Fibrous capsule of kidney
Renal fascia (anterior and posterior layers)

The renal parenchyma is enclosed by a thin but distinct Sagittal section through right kidney and lumbar region demonstrating vertical disposition of renal fascia

glistening membrane known as the fibrous (true) Lung

capsule of the kidney, which extends into the renal

sinus. Immediately surrounding the fibrous capsule is a Diaphragmatic fascia Diaphragm

variable amount of perinephric fat (perirenal fat (continuation of

capsule), which forms a matrix around the structures transversalis fascia) Liver

within the renal sinus. The perinephric fat also sur-

rounds the ipsilateral suprarenal gland. Costodiaphragmatic Bare area of liver

The kidneys, suprarenal glands, and perinephric fat recess
are all contained within a condensed, membranous layer
of renal fascia. The renal fascia consists of a stronger Suprarenal gland Fibrous capsule of kidney
posterior and more delicate anterior layer, previously
described as two separate structures (posterior fascia of Perinephric fat Peritoneum
Zuckerkandl and anterior fascia of Gerota) that fused
laterally to form the lateral conal fascia. At present, 12th rib Renal fascia (anterior
however, the renal fascia is regarded as a single and posterior layers)

structure. Paranephric fat Right kidney

The posterior layer originates from the lateral aspect

of the psoas fascia, fusing variably with the anterior Transversalis fascia Right colic (hepatic) flexure
layer of thoracolumbar fascia (quadratus lumborum

fascia) and transversalis fascia as it passes posterior and Quadratus lumborum muscle
lateral to the kidney. It then wraps around the anterior

aspect of the kidneys as the anterior layer. The medial Iliac crest
continuation of the anterior layer ensheaths the renal

vessels and fuses with the sheaths of the abdominal

aorta and inferior vena cava. In some individuals, these

fusions are very delicate and may rupture under pres-

sure, permitting midline crossing of accumulated fluid.

Another delicate fascial prolongation extends inferome-

dially along each ureter as periureteric fascia. the left. Other studies, however, have challenged the this technique was formerly used to visualize the

There is substantial disagreement over the cranio- notion that these spaces are closed, finding the peri- kidneys in a procedure known as retroperitoneal

caudal boundaries of the renal fascia, reflecting its nephric space to be continuous with the bare area pneumography.

tenuous and elusive structure. In their cranial aspect, between liver and diaphragm on the right and the sub- External to the renal fascia lies the retroperitoneal

the anterior and posterior layers are generally thought phrenic extraperitoneal space on the left. paranephric fat (pararenal fat body), a continuation of

to fuse superior to the suprarenal glands. In several Caudally, fusion of the anterior and posterior layers the extraperitoneal fat. The perinephric and paraneph-

studies this fused fascia appears to define a closed space is incomplete, which allows perinephric fluid to ric fat are both traversed by variably developed strands

on each side, which is then continuous with the dia- seep into the iliac fossa of the greater pelvis. Likewise, of collagenous connective tissue that extend from the

phragmatic fascia in the region of the coronary liga- air injected into the presacral space is known to renal fascia, which may cause them to appear multilami-

ment on the right and the gastrophrenic ligament on reach the perinephric space through this same opening; nate in sectional studies.

6 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-6 Anatomy of the Urinary Tract

ANATOMIC RELATIONS OF URETERS

URETERS: POSITION, RELATIONS, Ureters in male: anterior view Left kidney
GROSS STRUCTURE Right kidney
Left ureter
The ureters are paired muscular ducts that convey urine Duodenum
from the kidneys to the bladder. Each ureter begins Inferior
medial to the ipsilateral kidney as a continuation of the Superior mesenteric artery mesenteric artery
renal pelvis and ends upon insertion into the posterior Left psoas muscle
bladder wall. The ureters are retroperitoneal for their Right colic artery
entire length, which is approximately 30 cm. Left colic artery
Right ureter
The ureters vary in diameter from 2 to 8 mm, Sigmoid arteries
increasing in size in the lower lumbar area. They are Ileocolic artery
generally narrowest at their origin from the renal pelvis, Superior rectal
at the crossing of the pelvic rim, and at their termina- Right testicular vessels artery (cut)
tion as they traverse the bladder wall. As a result, renal
stones (see Plate 6-3) most often become impacted Right common Left genito-
within or proximal to these three sites. iliac artery femoral nerve
Left obturator
ABDOMINAL PORTION Right internal artery and nerve
iliac artery
As the ureters exit the kidneys, they pass anterior to the Left superior
psoas muscles and genitofemoral nerves. In addition, Right external vesical artery
the right ureter lies posterior to the second (descend- iliac artery
ing) part of the duodenum. More inferiorly, near their Left inferior
entry into the greater (false) pelvis, both ureters pass Middle rectal artery vesical artery
posterior to the gonadal vessels.
Diagonal course Left vas (ductus) deferens
The ureters also cross the unpaired vessels supplying of ureter through Urinary bladder
the intestines. The left ureter passes posterior to the bladder wall
left colic and sigmoid vessels, while the right ureter
passes posterior to the right colic, ileocolic, and termi- Bladder
nal superior mesenteric vessels. These vessels are con- mucosa
tained within the fusion fascia formed as the ascending
and descending portions of the colon became second- Ureter
arily retroperitoneal. Thus they do not have ureteric
branches and can be easily mobilized along with the Ureters in female: Urinary bladder Medial umbilical
colon to access the ureters. superior view ligament (occluded
part of umbilical artery)
As the ureters enter the lesser (true) pelvis, they Left ovary
pass anterior to the sacroiliac joint and common iliac Broad ligament Right superior vesical artery
vessels.
Uterosacral Round ligament
PELVIC PORTION (sacrogenital) of uterus
fold
The ureters enter the lesser pelvis anterior to the inter- Right uterine artery
nal iliac arteries. As they descend along the posterolat- Left ureter
eral pelvic wall, they run medial to the obturator Right umbilical
vessels/nerves and the superior vesical (umbilical) arter- Intersigmoid recess artery
ies. At the level of the ischial spines, the ureters turn
medially alongside branches of the hypogastric bundle Sigmoid mesocolon Right obturator
of nerves (see Plate 1-14). The other anatomic relation- Right common iliac artery artery and nerve
ships in the pelvic region differ between the two
genders. Right vaginal artery and inferior vesical branch Right external
iliac artery
Male. Just before the entering the bladder, each
ureter passes inferior to the ipsilateral ductus (vas) def- Right ovarian
erens. At this point the ureters lie superior and anterior vessels (cut)
to the seminal glands (vesicles).
Right internal
Female. As the ureters descend along the lateral walls iliac artery
of the lesser (true) pelvis, they course posterior and then Right ureter
parallel to the ovarian vessels contained in the suspen- Root of mesentery
sory ligaments of the ovary. The ureters pass medial to
the origins of the uterine arteries from the internal iliac the uterine arteries as the arteries course medially anteromedial direction within the wall of the bladder
arteries. As the ureters turn anteromedially from the toward the uterus. and then terminate at the ureteric orifices, which are
pelvic wall, they run anterior and parallel to the utero- 2 cm apart in the nondistended bladder. As intravesicu-
sacral fold, posterior and inferior to the ovaries. As they BLADDER INSERTION lar pressure increases, the intramural portions of the
traverse the base of the broad ligament, about 1.5 cm The ureters penetrate the thick wall of the bladder ureters become compressed, preventing reflux of urine.
lateral to the uterine cervix, the ureters pass inferior to about 2.5 cm from the midline. They run in an In this distended state, the ureteric orifices spread to
become 5 cm apart.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 7

Plate 1-7 Urinary System: VOLUME 5

POSITION AND RELATIONS OF URINARY BLADDER: MALE

Paramedian (sagittal) dissection

External iliac vessels

Parietal peritoneum Vas (ductus) deferens
Umbilical prevesical fascia Urinary bladder and vesical fascia
Ureter (cut)
Transversalis fascia Seminal gland (vesicle)

Rectus Rectovesical pouch
abdominis muscle

Sub- fatty Rectoprostatic/rectovesical
cuta- (Camper) (Denonvilliers) fascia
neous mem-
branous Rectum
tissue (Scarpa) Prostate
Ischiopubic ramus (cut)
Superior pubic Levator ani muscle
ramus (cut) Deep transverse
perineal muscle
Fundiform
ligament of penis

Suspensory Perineal body
ligament of penis
Deep External
Deep dorsal
BLADDER: POSITION, RELATIONS, vein of penis Superficial anal sphincter
GROSS STRUCTURE
Corpus Subcutaneous muscle
The urinary bladder is an expandable reservoir that cavernosum
receives urine from the ureters. When empty, the Deep perineal (investing
bladder lies entirely within the lesser pelvis and resem- Deep (Buck) or Gallaudet) fascia
bles a flattened, four-sided pyramid with rounded fascia of penis
edges. The apex, which corresponds to the tip of the Superficial perineal (Colles) fascia
pyramid, is directed anteriorly. Opposite the apex is the
base (fundus), the expansive posterior surface. Between Corpus Testis Retropubic (prevesical) space
the apex and fundus is the body of the bladder, which spongiosum
has a single superior surface, as well as two convex Superficial (dartos) fascia of penis and scrotum
inferolateral surfaces separated by a rounded inferior
edge. The bladder’s most inferior and most fixed aspect Median (sagittal) section
is known as the neck. It is located just proximal to the
outlet, also known as the internal urethral orifice. Urinary bladder

The bladder wall consists of a loose, outer connective Median umbilical ligament Tri- Ureteric orifice Rectovesical pouch
tissue layer, known as the vesical fascia; a three-layered Parietal peritoneum Apex Body Neck gone Fundus
muscularis propria of smooth muscle, known as the Vesical fascia
detrusor; and an internal mucosa. The ureters enter the Retropubic (prevesicle) Rectum
bladder on its posteroinferior surface and then take an space and venous plexus
oblique course through its wall before terminating at Seminal gland
the ureteric orifices. The two ureteric orifices, com- Pubic symphysis (vesicle)
bined with the internal urethral orifice, bound an inter- Fundiform ligament of penis
nal triangular region known as the trigone. Suspensory ligament of penis Prostate
Transverse perineal ligament
ANATOMIC RELATIONS Rectoprostatic/
Perineal membrane rectovesical
Anterior. The anterior portion of the bladder rests on (Denonvilliers)
the pubic symphysis and adjacent bodies of the pubic Corpus cavernosum fascia
bones; when empty, the bladder rarely extends beyond
their superior margin. Between the pubic bones/ Corpus spongiosum External urethral
symphysis and the bladder is the retropubic (prevesical) sphincter
space (of Retzius), which contains a matrix of loose
areolar tissue encasing the anterior portions of the Bulbourethral
vesical and prostatic venous plexuses. This space facili- (Cowper) gland
tates extraperitoneal access to the bladder and prostate
via suprapubic abdominal incision. Perineal body

As the bladder fills with urine, the body expands, Bulbospongiosus muscle
causing its anterosuperior aspect to ascend into the
extraperitoneal space superior to the pubic crest. The Superficial (dartos) fascia Deep perineal (investing
base and neck of the bladder, in contrast, remain rela- of penis and scrotum or Gallaudet) fascia
tively constant in both shape and position.
Deep (Buck) fascia of penis Superficial perineal (Colles) fascia
The apex of the empty bladder sends a solid, slender
projection known as the median umbilical ligament Glans penis and external urethral meatus Deep (Buck) fascia of penis

superiorly along the midline of the abdominal wall, peritoneal cavity. These fossae are divided by the
toward the umbilicus. This ligament represents a median umbilical ligament and bounded laterally by the
vestige of the urachus (see Plate 2-33) and rarely pos- obliterated umbilical arteries, which form the medial
sesses a residual allantoic lumen. If a lumen is present, umbilical ligaments. The level of the supravesical fossae
it infrequently may communicate with that of the (and consequently, the superior extent of the retropubic
bladder, but a urachus that is patent from bladder to the space) changes with bladder emptying and filling.
umbilicus is very rare.
Lateral. The walls of the bladder are covered by
Superior. The peritoneum covering the anterosupe- peritoneum to the level of the umbilical artery/medial
rior aspect of the bladder reflects onto the abdominal umbilical ligament. The reflection of the peritoneum
wall to form the paired supravesical fossae of the from the lateral walls of the bladder onto the lateral

8 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-8 Anatomy of the Urinary Tract

POSITION AND RELATIONS OF URINARY BLADDER: FEMALE

Median (sagittal) section

Parietal peritoneum

Recto-uterine pouch (cul-de-sac of Douglas) Transversalis fascia

Median umbilical ligament

Umbilical prevesical fascia

Uterus

Vesico-uterine pouch

Vesicovaginal fascia

Fundus Urinary bladder
Apex
Body
Ureteric orifice
Trigone
Neck

Pubic symphysis

Retropubic (prevesical) space

Inferior (arcuate) pubic ligament

Deep dorsal vein of clitoris

Internal urethral orifice

Transverse perineal ligament

External uretral sphincter and
Sphincter urethrovaginalis muscles

Urethra

BLADDER: POSITION, RELATIONS, Perineal body Vagina
GROSS STRUCTURE (Continued) Perineal membrane
Rectum External anal sphincter muscle

Rectovaginal fascia

pelvic walls forms the shallow paravesical fossae of the Superior view with peritoneum and vesical fascia removed
peritoneal cavity. These fossae extend posteriorly to
the vasa deferentia in males. In females, they extend to Pubic symphysis
the anterior aspect of the broad ligament, which conveys
the round ligaments of the uterus. Inferior to the para- Inferior (arcuate) pubic ligament
vesical fossae, the loose areolar tissue of the retropubic
space continues laterally. Deep dorsal vein of clitoris
Medial pubovesical ligament
Posterior. In the male, the two seminal glands (vesi- (medial puboprostatic ligament in male)
cles) and ampullae of the vasa deferentia lie between the Transverse perineal ligament (anterior
base of the bladder and the rectum on each side of thickening of perineal membrane)
the midline. These structures are separated from the Tendinous arch of levator ani muscle
rectum by the rectoprostatic (rectovesical) fascia cor
septum (also known as Denonvilliers fascia). This fascia Obturator canal
is continuous with the tough envelopes of the ampullae Lateral pubovesical ligament
of the vasa deferentia and seminal glands (vesicles), and (lateral puboprostatic ligament in male)
it continues posterior to the prostate until it reaches the Tendinous arch of pelvic fascia
perineal body. Superior fascia of pelvic diaphragm
(covering levator ani muscle)
In the female, the urethra and bladder are separated
from the vagina and cervix by the vesicovaginal fascia, Obturator fascia over
which normally contains a small amount of areolar obturator internus muscle
tissue. The vesicovaginal fascia, as well as the rectovagi- Urinary bladder pulled up and
nal fascia (or septum, located posterior to the vagina), back (vesical fascia removed)
together are homologous to the male rectoprostatic Median umbilical ligament (cut)
(rectovesical) fascia.
Inferior vesical and vaginal arteries
In males, the rectoprostatic (rectovesical) fascia is Ureter
located inferior to the rectovesical pouch, the inferior-
most extent of the peritoneal cavity. In the fetus, this Plate 1-6). At the base of the bladder, these folds contain urethral orifice is slightly more inferior. In the newborn,
pouch is a deeper excavation, which dips posterior to the terminal portions of the ureters and, in the male, the bladder is more abdominal than pelvic in position,
the prostate as far as the pelvic floor. In females, the the ductus deferens. and the urethral orifice may be situated as far superiorly
rectovaginal fascia is directly inferior to a similar space, as the pubic crest.
termed the recto-uterine pouch (cul-de-sac of Douglas). Inferior. Except for a variable layer of endopelvic
fascia, the neck of the bladder rests directly on the LIGAMENTOUS ATTACHMENTS
In the male, the peritoneum extends from the bladder pelvic floor muscles (e.g., levator ani) in females,
around each side of the rectum toward the sacrum as a whereas in males the prostate gland is interposed The inferior, subperitoneal aspect of the bladder is con-
pair of sickle-shaped shelves called the sacrogenital between them. In the male, the internal urethral orifice nected to the pubis by two ligaments originating in the
(vesicosacral) folds, bounding the pararectal fossae. In lies about 1 or 2 cm superior to, and 2 cm posterior to, prostatic fascia in males and vesical fascia in females.
the female, the sacrogenital (uterosacral) folds arise the subpubic angle. In the female, the position of the
from the dorsolateral walls of the uterine cervix (see

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 9

Plate 1-9 Urinary System: VOLUME 5

CORONAL CROSS-SECTIONS OF URINARY BLADDER

Female: frontal section

Parietal peritoneum
Paravesical fossa
Fundus
Interureteric crest
Left ureteric orifice
Trigone
Neck of bladder
Paravesical endopelvic fascia
and vesical venous plexus
Vesical fascia
Tendinous arch of levator ani muscle

Obturator internus muscle

Levator ani muscle

Tendinous arch of pelvic fascia

Urethra

Perineal membrane

Inferior pubic ramus

Crus of clitoris and ischiocavernosus muscle

Deep perineal (investing or Gallaudet) fascia

Superficial perineal (Colles) fascia

Bulb of vestibule and bulbospongiosus muscle

BLADDER: POSITION, RELATIONS, Vagina
GROSS STRUCTURE (Continued)
External urethral sphincter
Tendinous arch of pelvic fascia
Round ligament of uterus

The first of these ligaments is known as the medial Male: frontal section Parietal
puboprostatic ligament in males and the medial pubo- peritoneum
vesical ligament in females. This ligament lies close to Fundus
the pelvic floor and flanks the deep dorsal vein of the Interureteric crest Para-
penis (or clitoris) as it pierces up the pelvic floor to vesical
enter the prostatic (or vesical) venous plexus. Other Trigone fossa
ligaments flanking this vein include the inferior (arcuate) Vas (ductus) deferens
pubic ligament anteriorly, which forms the inferior Internal
margin of the pubic symphysis, and the transverse peri- Right ureteric orifice urethral
neal ligament posteriorly, which is an anterior thicken- sphincter
ing of the perineal membrane. Neck of bladder
Tendinous
The second ligament is known as the lateral pubo- Paravesical endopelvic fascia arch of
prostatic ligament in males and the lateral pubovesical and vesical venous plexus pelvic
ligament in females. This ligament is formed by a fascia
lateral extension of the prostatic (or, in females, vesical) Tendinous arch of
fascia over the inferior group of vesical arteries, puden- levator ani muscle Anterior
dal veins (draining the vesical plexus), and autonomic recess of
nerves. The terminal part of the ureter and (in males) Uvula ischio-
vas deferens contribute adventitia to this ligament. At Obturator internus muscle anal
its lateral edge, this ligament joins the superior fascia fossa
of the pelvic diaphragm, which invests the levator ani. Levator ani muscle
This linear area of attachment is known as the tendi- Prostate and prostatic urethra Inferior
nous arch of the pelvic fascia. pubic
Seminal colliculus ramus
BLADDER STRUCTURE Bulbourethral (Cowper) gland Crus of
penis and
The detrusor muscle, which contracts under parasym- Perineal membrane and ischiocaver-
pathetic stimulation, consists of three layers of muscle. external urethral sphincter nosus muscle
Unlike in the gastrointestinal tract, however, these Bulbous portion of spongy urethra
muscle layers are not clearly distinct in all areas. Corpus spongiosum and Superficial
bulbospongiosus muscle perineal
The outer muscle layer consists of predominantly Deep perineal (investing or Gallaudet) fascia (Colles) fascia
longitudinal fibers, which are especially numerous in
the midline region and near the neck. The thin middle this layer is intimately attached to the mucosa and combined with pressure from the neighboring middle
muscle layer encircles the fundus and body. In males, forms the trigonal muscle. lobe of the prostate (in males), leads to a small elevation
additional circular fibers create the internal urethral above the bladder neck known as the uvula.
sphincter in the inferior neck, which contracts during Around the ureteric orifices, the muscular coat of
sympathetically stimulated ejaculation to prevent reflux each ureter also fans out into the bladder. Some of these The innermost layer of the bladder is the mucosa.
of semen into the bladder. muscle fibers cross the midline to unite with strands When the bladder is empty, the mucosa is corrugated
from the opposite side, raising an interureteric crest. by numerous folds. As the bladder distends, however,
The innermost layer of the detrusor contains addi- the folds are obliterated. The mucosa of the trigone is
tional longitudinal fibers. In the region of the trigone, The sides of the trigone are outlined by yet another anatomically distinct, however, because it is firmly
group of submucosal fibers, known as Bell muscle, attached to the muscularis, consequently appearing
which connect the ureteral muscles with the wall of the smooth even when the bladder is empty.
urethra. Tension across these bands, especially when

10 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-10 Anatomy of the Urinary Tract

RENAL ARTERY AND VEIN IN SITU

RENAL VASCULATURE Inferior vena cava (cut) Esophagus (cut)

RENAL ARTERIES Right and left inferior Left inferior phrenic vein
phrenic arteries
At rest, 20% to 25% of the cardiac output circulates Left superior suprarenal arteries
through the kidneys. Accordingly, the renal arteries are Celiac trunk (cut)
major paired branches of the abdominal aorta. These Left middle
arteries arise from the abdominal aorta roughly at the Right superior suprarenal artery
level of the L1/L2 intervertebral disc, about 1 cm infe- suprarenal arteries
rior to the origin of the superior mesenteric artery. Left suprarenal
Right middle vein
Because the aorta is slightly to the left of the midline suprarenal artery
here, the left renal artery is shorter than the right. It Right suprarenal Left inferior
takes a nearly horizontal course to the left kidney. vein (cut) suprarenal
artery
Because the right kidney is positioned slightly infe- Right inferior
rior to the left kidney, the right renal artery arises either suprarenal
inferior to the origin of the left or, more frequently, artery
takes an oblique path. During its course, the right renal
artery passes posterior to the inferior vena cava. Extrahilar segmental Ureteric branch
(polar) artery of left renal artery
Both renal arteries run posterior and slightly cranial
to the corresponding renal veins. The arteries are Ureteric branch Left renal
surrounded by a dense plexus of nerve fibers that arrive of right renal artery artery and vein (cut)
by way of the celiac, superior mesenteric, and aorticore-
nal ganglia, located adjacent to the origins of the celiac, Right renal artery and vein (cut) Left testicular (ovarian)
superior mesenteric, and renal arteries. Right testicular (ovarian) artery and vein artery and vein

Anterior Relations. On the left, the body of the pan- Inferior vena cava (cut) Left 2nd lumbar vein
creas lies anterior or slightly superior to the left renal Abdominal aorta and communication to
artery, with the splenic vein between them. The inferior ascending lumbar vein
mesenteric vein may or may not be in close relationship
with the left renal vessels, depending on where it joins Inferior mesenteric artery (cut)
the splenic vein.
Superior mesenteric artery (cut)
On the right, the duodenum and the head of the
pancreas are adherent to the anterior surface of the Most of the time, the posterior branch continues as segmental vessels, a characteristic pattern has been
right renal artery (see Plate 1-1 for a picture of these the single posterior segmental artery, which runs identified. The superior and inferior segments, located
relationships). posterior to the renal pelvis. The anterior branch, in at the poles, receive the superior and inferior segmental
contrast, courses farther into the sinus before dividing arteries from the anterior branch of the renal artery. On
Posterior Relations. On the left, the left diaphrag- into two to four anterior segmental arteries, which the anterior surface, the area between the poles is
matic crus, psoas muscle, ascending lumbar vein (the enter the parenchyma between the veins and the renal divided into the anterior superior and anterior inferior
lateral root of the hemiazygos vein), and sympathetic pelvis. segments; these receive the anterior superior and ante-
trunk lie posterior to the renal artery. rior inferior segmental arteries from the anterior branch
Each segmental artery supplies a vascular renal of the renal artery. On the posterior surface, a single
On the right, the azygos vein, right lumbar lymphatic segment, a distinct portion of the kidney named for the posterior segment lies between the polar segments and
trunk, and right crus of the diaphragm lie posterior to segmental artery it receives. In kidneys with five
the proximal section of the renal artery. The psoas
muscle lies posterior to the middle section of the renal
artery.

Presegmental Branches. Each renal artery sends
slender inferior suprarenal arteries to the ipsilateral
suprarenal gland. The suprarenal glands also receive
middle and superior suprarenal arteries, which are
branches of the aorta and the inferior phrenic arteries,
respectively.

Each renal artery, as well as its segmental branches
near the hilum, also supplies numerous small branches
to the perinephric fat, renal fascia, renal capsule, renal
pelvis, and ureter.

Segmental Branches. Near the hilum, each renal
artery splits into a small posterior and a larger anterior
branch. These major branches, in turn, give rise to
segmental arteries, each destined for one of the kidney’s
wedge-shaped vascular segments. In most kidneys,
three to five segmental arteries supply the parenchyma
in a characteristic pattern.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 11

Plate 1-11 Urinary System: VOLUME 5
RENAL ARTERY SEGMENTAL BRANCHES AND INTRARENAL ARTERIES

Superior segmental artery Left kidney with five segmental
Anterior superior segmental artery renal artery branches

Interlobar arteries

Capsular and perirenal branches Lobar arteries

Inferior suprarenal artery

RENAL VASCULATURE (Continued) Anterior branch Arcuate arteries
of renal artery
receives the posterior segmental artery. The terminol- Cortical radiate
ogy is easily adjusted for kidneys with fewer than five Renal artery (interlobular)
segmental arteries/vascular segments via comparison arteries
with the five segment pattern. The superior or posterior Posterior branch of renal artery
segmental arteries/segments are most likely to be (posterior segmental artery) (Capsular)
absent. perforating
Pelvic and ureteric branches radiate artery
Segmental arteries do not anastomose with one
another. Therefore, occlusion or injury to a segmental Anterior inferior segmental artery
branch will cause segmental renal ischemia.
Inferior segmental artery
The border between the posterior and the two ante-
rior segments follows an intersegmental line (of Brödel), For simplicity, arcuate branches of arcuate arteries are not depicted. Most cortical radiate arteries arise
which runs along the lateral edge of the kidney on the from arcuate branches, but some arise directly from both arcuate and interlobar arteries, as shown here.
posterior surface. No major vascular channels are likely
to run beneath this line, which makes it a preferred area Vascular renal segments (five branch pattern) Anterior inferior segmental
for nephrotomy incisions. The area, however, is by no artery, with early bifurcation
means bloodless because segmental boundaries are not Superior
planar; rather, they are jagged, as small vessels of adja- Anterior
cent segments interdigitate along borders. Anterior Posterior superior
superior segmental
Intrarenal Arteries. Segmental arteries branch into artery
lobar arteries, each of which supplies a renal pyramid Anterior
or group of pyramids sharing a common apex. Just inferior Posterior
before entering the parenchyma, lobar arteries divide segmental
into two or three interlobar arteries. Often, segmental artery
arteries divide directly into interlobar arteries, skipping
the intermediate order of branching. The interlobar Catheter
arteries travel in the renal columns, near or alongside in abdom-
the pyramids, following a gently curving course toward inal aorta
the cortical arches.
Inferior
As each interlobar artery approaches the base of the
adjacent pyramid, it divides into several (four to six) Anterior surface Posterior surface Digital subtraction angiography of a left
arcuate arteries, which diverge at right angles, penetrat- of left kidney of left kidney kidney with three segmental renal artery
ing the cortical arch overlying the convex base of branches, as well as an early bifurcation.
the pyramid. Although multiple arcuate arteries partici-
pate in supplying the arch overlying each pyramid, turn back (recur) toward the renal sinus to supply the Accessory arteries are not duplicated vessels, but rather
arcuate arteries generally do not anastomose with one neighboring portion of the renal calyces and send one or more segmental (end) arteries uniquely respon-
another. branches into the apical aspect of the adjacent pyramid. sible for a portion of the kidney. Accessory arteries are
regarded as persistent embryonic lateral splanchnic
Arcuate arteries branch in turn (although for Anomalies of the Renal Artery. In about two thirds arteries. They may arise from the aorta as high as the
simplicity, this order of branching is usually omitted of individuals, a single renal artery passes to each diaphragm or as low as the internal iliac artery; however,
from two-dimensional illustrations) and these arcuate kidney. In the remainder, a variety of anomalies may they most frequently arise caudal to the main artery.
branches give rise to cortical radiate (interlobular) be seen. Most occur on the left side. Right accessory arteries
arteries. Although most cortical radiate arteries arise arising caudal to the main artery usually pass anterior
from arcuate branches, some arise directly from arcuate Roughly 1 in 10 kidneys, for example, receives addi- to the inferior vena cava (IVC).
or interlobar arteries. Some cortical radiate arteries tional branches from the aorta that enter at the hilum,
extend into the renal columns, whereas others extend known as accessory or supernumerary renal arteries.
through the arches. The chief purpose of the cortical
radiate arteries is to provide afferent arterioles to the
glomeruli (see Plate 1-19). Some of the arteries extend-
ing through the arches, however, may reach or pass
through the fibrous capsule as perforating arteries,
often establishing small connections with extracapsular
vessels.

Spiral arteries arise from interlobar arteries in the
renal columns, running a more tortuous course as they

12 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-12 Anatomy of the Urinary Tract
VARIATIONS IN RENAL ARTERY AND VEIN

Extrahilar segmental Extrahilar segmental
(polar) artery (polar) artery, with
branch to the
Duplicated suprarenal gland
renal
artery

RENAL VASCULATURE (Continued)

Up to one in four kidneys receives an extrahilar seg- Low accessory segmental artery
mental (polar) artery that passes directly to the superior passing anterior to the inferior vena cava
or inferior pole; half of these arise directly from the
aorta, and half arise as an early (proximal or prehilar)
segmental branch of the main renal artery. Accessory
inferior polar arteries crossing anterior to the ureter can
either cause or aggravate ureteric obstructions.

Finally, the renal arteries may give rise to branches
normally derived from other vessels, such as the inferior
phrenic, middle suprarenal, gonadal, pancreatic, or
colic arteries, as well as one or more of the lumbar
arteries.

RENAL VEINS

The venous branches draining the renal parenchyma Duplicated left renal Persistent left
converge within the renal sinus and, upon leaving the vein passing both IVC joining
hilum, unite to form the renal vein. The renal veins run anterior and posterior left renal vein
anterior and slightly caudal to the renal arteries to enter to the aorta, forming
the IVC. a ring. The posterior Duplicated
position is abnormal. left renal
Because the IVC lies on the right side of the vertebral vein
column, the left renal vein is nearly three times longer Aorta
than the right vein. Consequently, left kidneys are pre- Left
ferred as donor kidneys. Right kidney
kidney
The left renal vein runs posterior to the splenic vein
and body of the pancreas. It receives the left suprarenal Computed tomography (contrast-enhanced) of duplicated left renal vein
vein and the left gonadal (testicular or ovarian) vein. It
also connects with the hemiazygos vein by way of the interlobar veins following the general arterial pattern. common than those of the renal arteries. The major
ascending lumbar vein. It crosses the aorta anteriorly, These intrinsic renal veins have extensive collaterals. venous anomalies include duplicated or multiple renal
below the origin of the superior mesenteric artery, and veins. Duplicated veins are most common on the right
empties into the IVC at a level slightly superior to that Eventually the veins unite into four to six trunks that side, where they may pass both anterior and posterior
of the right renal vein. converge within the renal sinus, lying anterior but only to the renal pelvis. When present on the left side, a
in a roughly similar pattern to the segmental arteries. duplicated vein often runs posterior to the aorta, so
The right renal vein runs posterior to the upper Approximately 1 to 2 cm medial to the hilum, these that the aorta is encircled by two renal veins. In a
second (descending) part of the duodenum and may trunks join to form the renal vein. rarer anomaly, a persistent left inferior vena cava may
contact the head of the pancreas. It occasionally assists join the left renal vein.
in forming the azygos vein by means of a connecting Anomalies of the Renal Vein. Unlike in other vascu-
branch. Unlike the left renal vein, however, the right lar beds, anomalies of the renal veins are far less
renal vein does not receive the right gonadal or supra-
renal veins, which instead connect directly to the infe-
rior vena cava. The right renal vein joins the inferior
vena cava after a very short course, usually of 2 to
2.5 cm, but sometimes 1 cm or less.

Unlike the arterial supply, the venous system is safe-
guarded by collaterals. These include anastomoses
between renal veins, segmental veins, veins of the azygos
system, inferior phrenic veins, and rarely, the splenic
vein. The veins of the perinephric and paranephric fat
and renal fascia connect the subcapsular intrarenal chan-
nels with veins draining the adjacent body walls.

Tributaries of the Renal Vein. Numerous small sub-
capsular veins are grouped in tiny radial arrays called
stellate veins (see Plate 1-19). These communicate with
capsular and perinephric veins, as well as with intrarenal
veins. The stellate veins empty into the cortical radiate
(interlobular) veins which, in turn, drain into the
arcuate veins. The arcuate veins empty into the

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 13

Plate 1-13 Female (Anterior View) Urinary System: VOLUME 5

VASCULATURE OF URETERS Abdominal
AND BLADDER aorta
Superior
URETERS mesenteric
artery (cut)
The blood supply of the ureters is variable and asym- Renal artery
metric. Indeed, any nearby arteries that are primarily and vein (cut)
retroperitoneal or subperitoneal may provide branches Ureteric
to the ureters. branch from
renal artery
In the abdomen, consistent ureteric branches arise from Ovarian
the renal arteries, which supply the ureters either directly artery
or via a branch to the renal pelvis. Less consistent branches Ureteric branches
arise from the gonadal (testicular or ovarian) arteries, from ovarian
common and external iliac arteries, or aorta. These and common
branches extend laterally to the abdominal ureter, which iliac arteries
can thus undergo gentle medial traction during surgery. Ureter
Inferior
In the pelvis, consistent ureteric branches arise from mesenteric
the uterine arteries in females and the inferior vesical artery (cut)
arteries in males. Less consistent branches arise from the Ureteric
gonadal (testicular or ovarian), superior vesical, or inter- branch from
nal iliac arteries. These branches extend medially to the aorta
pelvic ureter, which can thus undergo gentle lateral trac- Median sacral
tion during surgery. In this region, the ureter is adherent artery
to the posterior aspect of the serosa and thus also receives Common iliac
small twigs from minor peritoneal arteries. artery
Internal iliac
As all of these branches reach the ureter, they divide artery
into ascending and descending limbs that form longitu- Iliolumbar artery
dinal, anastomotic meshes on the outer ureter wall. These Superior gluteal
meshes usually establish functional collateral circulation; artery
however, in approximately 10% to 15% of individuals, Lateral sacral
sufficient collaterals do not form. Furthermore, ureteric artery
branches are small and relatively delicate. Thus disrup- Inferior gluteal
tion of these branches may lead to ischemia. During and internal
surgical procedures, the location, disposition, and arterial pudendal arteries
supply of the ureters must be carefully evaluated. Umbilical artery
(patent part)
The distribution of ureteric veins follows that of the Obturator artery
arteries. These vessels drain to the renal vein; the infe- Uterine artery
rior vena cava and its tributaries; and the endopelvic Inferior vesical
venous plexuses. artery and
ureteric branch
URINARY BLADDER Superior vesical
arteries
The arterial supply to the urinary bladder arises from Inferior epigastric
the fanlike ramification of the internal iliac vessels, artery
usually from the anterior branches. Although the Ureteric branch
branching pattern of the internal iliac vessels is variable, from superior
the arteries that ultimately reach the bladder are quite vesical artery
consistent. In general, two main arteries (or groups of Medial umbilical
arteries) may be distinguished: ligament
1. The superior vesical arteries each arise as one or more
The inferior vesical arteries ramify over the Vesical veins are short, uniting into a rich vesical
branches of the patent umbilical arteries, usually just fundus and neck of the bladder. On their way to the venous plexus around the base of the bladder. In males,
below the level of the pelvic brim. Beyond the origin bladder, the arteries pass through the lateral liga- this plexus is continuous with the prostatic venous
of these branches, the umbilical arteries obliterate ments of the bladder, where they usually give off plexus.
after birth, forming the medial umbilical ligaments. ureteric branches and (in the male) branches to the
seminal glands (vesicles) and prostate. In males, the The vesical plexus (or prostatic plexus in males)
The superior vesical arteries provide the most con- inferior vesical arteries may give rise to the deferen- communicates with the veins of the perineum, receiving
stant and significant blood supply to the bladder. The tial arteries. the dorsal vein of the clitoris (or penis). Multiple inter-
branches course over the body and fundus of the connecting channels lead from the plexus to the inter-
bladder. They anastomose with each other, with their In some, the bladder receives additional branches nal iliac veins. Anastomoses with the parietal veins of
contralateral fellows, and with branches of the inferior from the obturator, inferior gluteal, or internal the pelvis establish connections to the internal vertebral
vesical arteries. Their dynamic tortuosity and overall pudendal arteries. venous plexus, thighs, and gluteal regions.
length allow for the changes in bladder size that occur
with filling and emptying. Superior vesical arteries THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS
may also give rise to ureteric branches and, in males,
to the deferential arteries. In infants, a small urachal
branch may extend toward the umbilicus, sometimes
anastomosing with the inferior epigastric arteries.
2. The inferior vesical arteries may arise as independent
branches of the internal iliac arteries, in common
with the middle rectal arteries, or—commonly in
females—from the uterine artery (directly or via
vaginal branches).

14

Plate 1-14 Anatomy of the Urinary Tract

INNERVATION OF KIDNEYS, URETERS AND BLADDER

Anterior vagal trunk

Posterior vagal trunk

Greater thoracic splanchnic nerve

Celiac ganglia and plexus

Lesser thoracic splanchnic nerve

Superior mesenteric ganglion

Least thoracic splanchnic nerve

Aorticorenal ganglion

Renal plexus and ganglion

2nd lumbar splanchnic nerve

Ureteric branches
from intermesenteric plexus

Intermesenteric (aortic) plexus

Inferior mesenteric ganglion

Sympathetic trunk and ganglion

Middle ureteric branch

Superior hypogastric plexus

Lumbosacral trunk

INNERVATION OF URINARY Sacral splanchnic nerves
SYSTEM (branches from upper sacral
sympathetic ganglia to
hypogastric plexus)

Gray ramus communicans

Hypogastric nerves

The urinary system receives a rich nerve supply from Lumbosacral plexus
the autonomic nervous system, which is accompanied
by visceral afferent nerve fibers. The autonomic nervous Pelvic splanchnic nerves
system facilitates bladder filling and stimulates empty-
ing, whereas visceral afferent fibers from the bladder Inferior hypogastric (pelvic) plexus
convey sensations produced by distention. with periureteric loops and
branches to lower ureter
Once toilet training is complete, voiding can be con-
sciously inhibited by somatic efferent fibers that stimu- Rectal plexus
late contraction of the external urethral sphincter.
Likewise voiding can be consciously enhanced by con- Vesical plexus
traction of the diaphragm and abdominal wall muscles,
which further compress the contracting bladder. Prostatic plexus

SYMPATHETIC possibly sacral splanchnic nerves. Together, these The pathway of sympathetic innervation to the
nerves convey presynaptic fibers to the prevertebral remainder of the ureters and urinary bladder begins
Anatomy. Sympathetic innervation of the urinary ganglia, such as the celiac and aorticorenal ganglia, with presynaptic fibers originating in the T12-L2(3)
system begins in the lower thoracic and upper lumbar located near the major branches of the abdominal aorta. levels of the IML. These fibers travel through lumbar
(T10-L2 or 3) spinal cord segments, where neurons of The presynaptic neurons synapse in these ganglia with (and possibly sacral) splanchnic nerves and then the
the intermediolateral (IML) cell column give rise to postsynaptic neurons. intermesenteric (aortic) plexus, then synapse with
presynaptic (preganglionic) sympathetic fibers. These neurons in the inferior mesenteric ganglion or small
fibers exit the CNS via the anterior roots of the cor- The pathway of sympathetic innervation to the ganglia of the aortic/hypogastric plexuses. Postsynaptic
responding spinal nerves, traverse the initial parts of kidneys and upper ureter (see Plate 1-15) begins in fibers descend into the pelvis via aortic, hypogastric,
those spinal nerves, then exit via white rami communi- presynaptic fibers originating in the T10-L1 levels of and pelvic (vesical) plexuses to reach the ureters and
cans to reach the sympathetic trunks. the IML. These fibers travel through splanchnic nerves bladder.
to synapse with neurons of the superior mesenteric gan-
Within the sympathetic trunks, some fibers descend glion, aorticorenal ganglia, and the small ganglia in the Function. In the kidney, sympathetic tone has numer-
through the paravertebral ganglia to lower levels, but periarterial renal plexuses. Postsynaptic fibers reach the ous effects on both the vasculature and renal tubules.
all of them leave the trunks, without synapsing, in vis- kidney and upper ureter via periarterial plexuses and Adrenergic receptors are located throughout the renal
ceral branches. These branches, also known as the branches. cortex and outer stripe of the outer zone of the renal
abdominopelvic splanchnic nerves, extend from the
medial aspects of the trunks. They include the lesser
thoracic (T10-11), least thoracic (T12), lumbar, and

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 15

Plate 1-15 Urinary System: VOLUME 5

INNERVATION PATHWAYS OF THE KIDNEYS AND UPPER URETER Nucleus of
Spinal sensory (dorsal root) ganglion solitary tract

Gray ramus communicans Posterior (dorsal)
nucleus of vagus
nerve

Medulla
oblongata

Vagus nerve (X)

Ventral ramus of T10 Descending
(intercostal nerve) fibers

White ramus Ascending
communicans T10 fibers

(Paravertebral) Spinal cord
ganglia of T11 segments
sympathetic
trunk T10–L1

1st lumbar T12 Lesser thoracic
splanchnic splanchnic nerve
nerve
L1
Least thoracic
splanchnic nerve

Celiac ganglia

INNERVATION OF URINARY Superior
SYSTEM (Continued) mesenteric
ganglion

Aorticorenal
ganglion

medulla, with the greatest density in the juxtamedullary Renal artery,
region of the inner cortex. Graded increases in renal ganglion,
sympathetic tone cause renin release from juxtaglo- and plexus
merular granular cells (see Plate 3-18), increase renal
tubular sodium reabsorption, and decrease renal blood Sympathetic fibers
flow (by constricting afferent arterioles). These com- Pre-synaptic (pre-ganglionic)
bined effects can contribute to the development and Post-synaptic (post-ganglionic)
maintenance of hypertension. In experimental animals,
for example, renal denervation is known to prevent or Parasympathetic fibers
ameliorate hypertension. Likewise, in patients with Pre-synaptic (pre-ganglionic)
drug-resistant essential hypertension, catheter-based Post-synaptic (post-ganglionic)
radiofrequency renal denervation results in substantial
and sustained reductions in systemic blood pressure. Afferent fibers

Some renal sympathetic nerve fibers release dopa- arranged to form an internal urethral sphincter, which sources send presynaptic fibers all the way to the target
mine, but there is no evidence that dopamine released prevents ejaculation into the bladder. As a result, stress organ, where they synapse with intrinsic (intramural)
during sympathetic stimulation affects renal function. may interfere with the ability to urinate by contracting postsynaptic neurons.
Thus dopamine is not considered an endogenous neu- this muscle. In females, in contrast, sphincteric arrange-
rotransmitter in the kidney. Likewise, despite the pres- ment of trigonal muscle is not evident. The cranial source, which innervates the kidneys and
ence of acetylcholinesterase, renal sympathetic nerve upper ureters, is the vagus nerve; it conveys presynaptic
stimulation is not affected by anticholinergic agents. PARASYMPATHETIC fibers through the celiac and aorticorenal ganglia to the
intrinsic renal and upper ureteric plexuses.
In the ureter, peristalsis is primarily myogenic in Anatomy. Parasympathetic innervation of the urinary
nature, driven by specialized pacemaker cells (see Plate system is derived from cranial and sacral sources. Both The sacral source, which innervates the remainder of
1-27). The efferent and afferent fibers of the extrinsic the ureters and bladder, begins in the S2-S4 spinal cord
plexus, however, do appear to be involved in regulating segments, which contains neurons that give rise to
the pacemaker cells.

In the bladder, activation of β-adrenergic receptors
causes relaxation of the detrusor muscle, which facili-
tates bladder expansion during filling. Meanwhile, acti-
vation of α-adrenoceptors facilitates contraction of the
trigone muscle. In males, trigonal muscle is circularly

16 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-16 Anatomy of the Urinary Tract
INNERVATION PATHWAYS OF THE URETER AND BLADDER

Spinal sensory Dorsal (posterior) root Celiac ganglia
(dorsal root) Ventral (anterior) root Superior mesenteric ganglion
ganglia Aorticorenal ganglion
White Rami communicantes Renal artery and plexus
L1 Gray Intermesenteric (aortic) plexus

L2

Lumbar part L2 spinal nerve 1st and 2nd Inferior mesenteric ganglion
of spinal cord (ventral ramus) lumbar splan- Superior hypogastric plexus
chnic nerves Hypogastric nerves
Sacral part Sympathetic
of spinal trunk Ureter Inferior hypogastric
cord (pelvic) plexus
Sacral
Ascending Descending splanchnic Urinary bladder
fibers fibers nerves
PPoorrwttiwioiotinhnthoooufsftebbrslolaeasdrdaoddseaerr
Gray rami
communicantes

S2

S3

INNERVATION OF URINARY S4
SYSTEM (Continued)

presynaptic parasympathetic fibers. These fibers enter Sacral plexus Pudendal nerve
the initial portions of spinal nerves S2-S4 and then exit Pelvic splanchnic nerves Vesical plexus
via pelvic splanchnic nerves, which convey them to the Prostatic plexus
intrinsic plexuses of the ureters and bladder. Of note,
the upper ureter may receive branches of these para- External urethral sphincter
sympathetic fibers, even though its primary source of Bulbospongiosus muscle
parasympathetic innervation is the vagus nerve.
Sympathetic fibers Pre-synaptic (pre-ganglionic)
Function. In the kidney, the role of vagal (choliner- Post-synaptic (post-ganglionic)
gic) function is unclear. In the ureter, parasympathetic
stimulation probably modulates intrinsic pacemaker Parasympathetic fibers Pre-synaptic (pre-ganglionic)
cells. Post-synaptic (post-ganglionic)

In the bladder, parasympathetic stimulation triggers Somatic efferent fibers
contraction of the detrusor muscle and, by inhibiting
sympathetic tone, also indirectly relaxes the trigonal Afferent fibers
muscle. In males, relaxation of the trigonal muscle
includes relaxation of the internal urethral sphincter. sympathetic chain. The pain of pyelonephritis, or of an reach cranial and sacral sensory ganglia. Thus, the vis-
The combination of detrusor contraction and sphincter impacted stone in the renal pelvis or abdominal ureter, ceral afferents conducting pain impulses from subperi-
relaxation enables micturition. is experienced at levels T10-L1. The sensation of a toneal viscera have cell bodies located in the S2-S4
distended bladder is experienced in T12-L2. spinal sensory ganglia, with sensations perceived in the
AFFERENT corresponding dermatomes. Mechanoreceptors and
In contrast, afferent fibers conveying pain from chemoreceptors that play a role in renorenal reflexes
Afferent innervation from the urinary system carries organs without serosa (i.e., subperitoneal viscera, such also send projections along vagal afferent fibers to vagal
pain sensations and also plays a critical role in intrinsic as the neck of the bladder, terminal ureters, prostate, sensory ganglia. Likewise, the reflexive emptying of a
reflexes. The pathways for pain sensation depend on cervix, and upper vagina), as well as fibers involved in moderately distended bladder, such as occurs in infants,
whether the organ is invested with serosa. In those reflex arcs, generally follow the pathways of parasym- is transacted at sacral levels.
organs with serosa, such as the kidneys, abdominal pathetic innervation in a retrograde direction until they
ureters, and superior surface of the bladder, afferent
pain fibers follow the pathways of sympathetic inn-
ervation in a retrograde direction until they reach
spinal sensory ganglia. Referred pain from these organs
is experienced at the dermatomes corresponding to
the levels where the presynaptic fibers enter the

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 17

Plate 1-17 Perinephric fat Urinary System: VOLUME 5

LYMPHATICS OF Pericapsular lymphatic plexus
URINARY SYSTEM Subcapsular lymphatic plexus

Cortical lymph vessels along cortical radiate (interlobular) arteries
Lymph vessels along arcuate arteries
Lymph vessels along interlobar arteries
Medullary lymph vessels

LOWER URINARY TRACT Note: Arrows indicate nodes—a sequential chain of nodes that drains next to
direction of flow. the lumbar (caval/aortic) nodes. The lymph of the
In both the bladder and ureters, lymph first drains into upper ureters and kidneys drains directly into the
a submucous network of lymph capillaries. These capil- Lumbar lymph trunks superior lumbar nodes. In both cases, lymph from the
laries drain into a plexus located outside of the muscular to cisterna chyli lumbar nodes ultimately flows to the thoracic duct via
wall. This plexus, in turn, connects to vessels that lead and thoracic duct the lumbar lymph trunks.
to regional lymph nodes. The vessels contain valves,
whereas the plexus and capillaries do not. Lumbar (postcaval,
precaval, and lateral
Bladder. The apex and body of the bladder drain into aortic) nodes
vessels that reach the external iliac nodes (some via
prevesical and paravesical visceral nodes). The fundus Common iliac nodes
and neck drain into vessels that reach the internal iliac
nodes (some via postvesical visceral nodes). Promontorial (middle
sacral) node
Ureter. The pelvic portion of the ureter is drained
by a few lymph vessels that reach the internal iliac nodes Internal iliac nodes
either directly or via efferent vessels from the bladder.
The abdominal portion of the ureter has channels that External iliac nodes
drain into the external and common iliac nodes. Near
the kidney, drainage is to the lumbar (caval and lateral Lymph vessels from fundus
aortic) nodes, either by direct communication or via and neck of bladder
renal lymphatic trunks.
Lymph vessels from apex
KIDNEY and body of bladder

Extrarenal. Beneath the surface of the kidney, a scanty Paravesical and prevesical
subcapsular plexus of lymph capillaries anastomoses, by visceral nodes
means of perforating channels, with pericapsular vessels
in the perinephric fat. These vessles eventually drain urine. Its primary function is probably to return reab-
into superior lumbar nodes. The subcapsular plexus sorbed protein to the blood. Some investigators have
also communicates sparingly with lymphatics in the determined that the concentration of renin is greater in
deeper layers of the parenchyma. renal lymph than in renal vein plasma.

Intrarenal. In the parenchyma, lymph capillaries SUMMARY
accompany the blood vessels and are found chiefly in The lymph drainage of the bladder and ureters passes
the perivascular connective tissue. The lymph capillar- to the external, internal, and common iliac groups of
ies that surround arterioles are generally larger and
more numerous than those that surround venules.

The great majority of intrarenal lymphatics occur in
the cortical and corticomedullary zones. In the outer
cortex most lymphatics are associated with subcapsular
veins and renal tubules, whereas in the midcortex
they are associated with cortical radiate (interlobular)
arteries and veins, glomeruli, and tubules. In the corti-
comedullary zone, lymphatics pass between loops of
Henle and collecting ducts. In the medulla, sparse lym-
phatic channels drain structures in the region of the
vasa recta.

The lymph vessels exiting the parenchyma reach the
renal sinus, often accompanying the arteries along
the way, and form some four to five trunks that exit the
hilum. They are joined by lymph vessels from the renal
capsule and converge into a few valve-studded renal
lymphatic trunks that accompany the renal vein. These
trunks primarily drain to the superior lumbar nodes.

Except as a potential metastatic pathway, renal lym-
phatic drainage is commonly overlooked. The volume
of lymph that drains from the kidney, however, is
approximately 0.5 mL/min, thus approaching that of

18 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-18 Anatomy of the Urinary Tract

OVERVIEW OF THE NEPHRON Long-looped nephron Short-looped nephron

Fibrous capsule

Each kidney possesses an average of 600,000 to 1,400,000 Subcapsular zone Superficial glomerulus
tubular structures called nephrons, which contain a Proximal convoluted tubule
series of histologically distinct segments that alter the Renal cortex Juxtamedullary glomerulus Distal Distal convoluted tubule
concentration and contents of urine. The major seg- convoluted Proximal straight tubule
ments of each nephron are known as the glomerulus, tubule
proximal tubule, thin limb, distal tubule, and collecting Henle’s loop
duct. The proximal and distal tubules are both divided Proximal convoluted
into convoluted and straight parts, while the thin limb is tubule Thick ascending limb
divided into descending and ascending parts. (distal straight tubule)
Proximal
The arrangement of these different nephron seg- Outer zone Outer straight
ments gives rise to the two grossly visible zones in the stripe tubule
kidney, known as the cortex and medulla. The medulla
is divided into an outer zone (which is further subdi- Inner Thick Henle’s Descending thin limb
vided into outer and inner stripes) and an inner zone. stripe ascending loop Collecting duct
The boundaries of these various regions are marked by limb
the transition sites between different nephron seg-
ments, as described later. Renal medulla (pyramid) Descending Glomerular capillaries
Inner zone thin limb and Bowman’s capsule
GLOMERULUS AND PROXIMAL
CONVOLUTED TUBULE Ascending Afferent and efferent
thin limb glomerular arterioles
The initial formation of urine occurs at the interface
between the glomerular capillaries, which are arranged Proximal convoluted tubuleHenle’s loop
in a spherical tuft, and the first part of the nephron, Proximal straight tubule
an epithelial-lined sac known as Bowman’s capsule.
The glomerular capillaries and Bowman’s capsule are Thin limb
together knows as the glomerulus (or renal corpuscle).
As blood from an afferent arteriole passes through the Opening Thick ascending limb
glomerular capillaries, plasma and non–protein bound of papillary (distal straight tubule)
solutes are filtered into the area bounded by Bowman’s duct Distal convoluted tubule
capsule, known as Bowman’s space, to form primitive
urine. All nonfiltered blood is carried away from the Macula densa
glomerular capillaries in an efferent arteriole.
Cribriform area of renal papilla Collecting ducts
Bowman’s space conveys the primitive urine to the
first part of the proximal tubule, known as the proximal this point it transitions to the thick ascending limb, where it transitions to the distal convoluted tubule.
convoluted tubule, which takes a very tortuous course which courses back toward the cortex. Near this transition point is a specialized group of cells
through a small region of the cortex. The proximal con- known as the macula densa, which make direct contact
voluted tubule then transitions to the proximal straight Thus, based on the above descriptions, two different with the nephron’s parent glomerulus.
tubule, which is the first part of the loop of Henle. populations of nephrons can be distinguished: short-
looped nephrons, which are associated with superficial The distal convoluted tubule, like the proximal con-
LOOP OF HENLE and midcortical glomeruli, and long-looped nephrons, voluted tubule, takes a very tortuous course within a
which are associated with juxtamedullary glomeruli. small area of the cortex. It transitions to a short con-
After the proximal convoluted tubule, each nephron Long-looped nephrons have higher urine-concentrating necting segment (or tubule), which in turn leads to the
plunges into the medulla, makes a hairpin turn, and capabilities than short-looped nephrons (see Plate collecting duct.
then returns to the cortex near its parent glomerulus. 3-15); however, short-looped nephrons are far more
This region of each nephron is known as the loop of numerous, accounting for 85% of the total nephron The collecting duct courses from the cortex toward
Henle, and it contains the proximal straight tubule, thin population in humans. the medulla adjacent to ducts from neighboring neph-
limb, and distal straight tubule (more commonly known rons. In the inner zone of the medulla, these individual
as the thick ascending limb). DISTAL CONVOLUTED TUBULE, CONNECTING ducts join to form larger ducts. By a succession of
TUBULE, AND COLLECTING DUCT several such junctions, the papillary ducts are formed,
The proximal straight tubule, described above, origi- which arrive at the cribriform area of the papillae to
nates in the cortex and courses to the border between The thick ascending limb, as described in the previous drain urine into the minor calyces.
the outer and inner stripes of the outer zone of the section, courses from the medulla toward the cortex,
medulla. It then transitions to the first part of the thin
limb, known as the descending thin limb.

The remaining structure of the loop of Henle differs
based on the location of the nephron’s parent glomeru-
lus. In nephrons associated with glomeruli in more
superficial regions of the renal cortex, the descending
thin limb continues until reaching the border between
the inner zone of the medulla and the inner stripe of
the outer zone of the medulla. At this point, it transi-
tions to the thick ascending limb, which makes a hairpin
turn and courses back toward the cortex.

In nephrons associated with glomeruli near the cor-
ticomedullary border (known as juxtamedullary glom-
eruli), the descending thin limb plunges deep into the
medulla, makes a hairpin turn near the papilla, and
continues as the ascending thin limb until the border
between the outer and inner zones of the medulla. At

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 19

Plate 1-19 Urinary System: VOLUME 5

RENAL MICROVASCULATURE Afferent arteriole
Superficial glomerulus
The renal segmental arteries divide into lobar and then Efferent arteriole
interlobar arteries, which enter the renal (cortical)
columns and course alongside the pyramids (see Plate Afferent arteriole Cortical capillary plexus
1-10). As each interlobar artery approaches the base of Juxtamedullary glomerulus
its adjacent pyramid, it divides into several arcuate
arteries. Efferent arteriole

Both interlobar and arcuate arteries give rise to corti- Cortical radiate (interlobular)
cal radiate (interlobular) arteries. Those cortical radiate artery and vein
(interlobular) arteries that reach the fibrous capsule
form capsular and perforating branches that communi- Stellate Capsular and perforating
cate with extracapsular vessels. The capsular and perfo- veins arteries and veins
rating veins, as well as a dense subcapsular plexus of
stellate veins, drain into the cortical radiate (interlobu- Renal capsule
lar) veins, which drain into the arcuate and then inter-
lobar veins. Subcapsular
zone
The main purpose of the cortical radiate (interlobular)
arteries, however, is to give rise to afferent arterioles. Renal cortex Arcuate
Each afferent arteriole gives rise to a glomerulus, which artery
is responsible for filtering blood into a nephron. Afferent and vein
arterioles located near the outer cortex give rise to super-
ficial and midcortical glomeruli, associated with short- Vasa recta
looped nephrons, while afferent arterioles located in the
inner cortex give rise to juxtamedullary glomeruli, asso- Vasa recta
ciated with long-looped nephrons. emerging
directly
In both cortical and juxtamedullary glomeruli, the from arcuate
blood that remains in the glomerular capillaries after artery (via
filtration drains into efferent arterioles. Because the an aglom-
glomerular capillary bed thus lies between two arteri- erular shunt)
oles, an arrangement not seen elsewhere in the vascu-
lature, the pressure across the capillary walls can be very
finely adjusted in response to homeostatic demands.

The appearance and branching pattern of the effer-
ent arterioles differ based on the glomerulus type.

SUPERFICIAL GLOMERULI Renal medulla (pyramid) Short-looped
nephron
At superficial glomeruli, the efferent arterioles are nonfenestrated. The vessels of the (ascending) venulae Venulae
small, containing only one layer of smooth muscle cells. recta, in contrast, do not contain a smooth muscle layer, recta
These arterioles divide into a dense plexus of peritubu- and their endothelial cells are fenestrated. The func-
lar capillaries, which surrounds the cortical segments of tional significance of these differences is not well Interlobar
short-looped nephrons. This plexus drains into the cor- understood. artery
tical radiate (interlobular), arcuate, and then interlobar and vein
veins. The association of vasa recta with the loops of Henle
and collecting ducts forms the anatomic substrate for Renal
The peritubular capillaries have fenestrae that contain the countercurrent exchange system, which is critical column
negatively charged diaphragms, which permit a selective for the production of concentrated urine (see Plate (of Bertin)
exchange of materials with adjacent tubules. These dia- 3-12). Some illustrations depict each individual nephron Long-looped
phragms consist of 7-nm wide, criss-crossed fibrils that as being consistently associated with the vasa recta nephron
intersect at a central area like spokes of a wheel. In addi- Collecting
tion, tiny microfibrils anchor the peritubular capillaries duct
to the basement membranes of the renal tubules, holding Lobar
these structures in close approximation. artery and
vein
JUXTAMEDULLARY GLOMERULI
derived from its own efferent arteriole. It is now under-
At juxtamedullary glomeruli, the efferent arterioles are stood, however, that each nephron is invested with vasa
larger and contain multiple layers of smooth muscle recta derived from numerous efferent arterioles.
cells. Some of these arterioles form a capillary plexus that
surrounds the cortical segments of long-looped neph- Advanced age and certain types of chronic kidney
rons. Most, however, descend directly into the medulla disease are associated with degeneration of glomerular
as long branching loops known as vasa recta, which travel vessels. In the cortex, this is often enough to obliterate
parallel to the loops of Henle and collecting ducts. The postglomerular flow altogether. Near the medulla,
vessels of the (descending) vasa recta make hairpin turns where the efferent arterioles are thicker, such degenera-
in the inner medulla to become (ascending) venulae tion gives rise to aglomerular shunts that connect affer-
recta, which return to the corticomedullary junction and ent and efferent arterioles. In this case, vasa recta may
drain into arcuate and then interlobar veins. emerge directly from arcuate and interlobular arteries.

The vessels of the (descending) vasa recta contain a
layer of smooth muscle cells that regulate flow in
response to hormonal input. The endothelial cells that
line the inner surface of the vessels are continuous and

20 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-20 Anatomy of the Urinary Tract

Afferent arteriole STRUCTURE AND HISTOLOGY OF THE GLOMERULUS
Basement membrane
Endothelium
Glomerular basement membrane Parietal epithelial cell Bowman’s
Basement Endothelium capsule
membrane Visceral epithelial cell
(podocyte)
Smooth
muscle Granular cells

Bowman’s
space

Endothelial
fenestrations

Thick Proximal
ascending tubule
limb

Macula densa

GLOMERULUS Extra-
glomerular
mesangium

The glomerulus (or renal corpuscle) consists of the Efferent Mesangial matrix and cell
glomerular capillaries and the epithelium-lined sac that arteriole
surrounds and invests them, known as Bowman’s
capsule. Parietal epithelial cell

The glomerular capillaries originate from the affer- Afferent arteriole Lumen of capillary loop
ent arteriole and drain into an efferent arteriole. They
are arranged in a tuft about 200 μm in diameter, which Thick ascending limb Bowman’s space
is anchored to a central stalk of mesangial cells and Juxtaglomerular
matrix. The walls of the glomerular capillaries contain Glomerular basement
three layers. The innermost layer consists of endothe- apparatus Extraglomerular membrane
lial cells. The second layer consists of glomerular base-
ment membrane (GBM). The outermost layer consists mesangium Endothelial cell
of podocytes, also known as visceral epithelial cells.
Macula densa Visceral epithelial
Bowman’s capsule, the first part of the nephron, con- cell (podocyte)
sists of the two layers of epithelial cells that invest the
glomerular capillaries. The podocytes (visceral epithe- Mesangial cells
lial cells) in the capillary wall constitute the inner layer
of Bowman’s capsule. The parietal epithelial cells, Red blood cell
which are continuous with the podocytes at the base of in capillary loop
the capillary tuft, constitute its outer layer. The area
between the podocyte and parietal epithelial cell layers Light microscopy of a normal glomerulus
is known as Bowman’s space. (silver stain, 40ϫ magnification).

THE CAPILLARY WALL near the mesangial stalk, so as not to interfere with endothelial cells and podocytes, and it consists of three
filtration. These cells contain fenestrations that are layers: a thin lamina rara interna, a thick central lamina
As blood passes through the glomerular capillaries, approximately 70 to 100 nm in diameter, which may densa, and a thin lamina rara externa. Together, these
plasma and small, non–protein bound solutes are freely serve as an initial size-based filtration barrier. The cell layers measure approximately 300 to 350 nm across,
filtered across the three layers of the capillary wall into surfaces are also coated with a negatively charged gly- being somewhat thicker in males than in females. The
Bowman’s space, which leads to the proximal tubule. cocalyx that projects into the fenestrations and provides GBM consists primarily of type IV collagen and other
These three capillary wall layers, however, act as a criti- a charge-based filtration barrier. proteins, such as laminin and nidogen (also known as
cal barrier to the filtration of cells and larger plasma mol- entactin). The tight arrangement of these proteins con-
ecules, such as proteins, based on their size and charge. The GBM lines the outer surface of the endothelial tributes to the size-based filtration barrier. In addition,
cells and is continuous with the basement membrane the GBM contains negatively charged proteoglycans
The endothelial cells, which line the inner surface of of Bowman’s capsule. It is synthesized by both
the capillaries, are inconspicuous and possess a thin,
attenuated cytoplasm. Their nuclei are generally located

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 21

Plate 1-21 Urinary System: VOLUME 5

FINE STRUCTURE OF THE GLOMERULUS

Endothelial fenestrations Glomerular basement membrane

Podocytes (visceral epithelial cells)

Endothelial cell nucleus Foot processes (pedicles)

Subpodocyte space

Lumina of capillaries

GLOMERULUS (Continued)

that contribute to the charge-based filtration barrier. Mesangial cells Interdigitating foot processes
The potential space between the endothelial cells and Mesangial matrix with slit diaphragm
GBM is known as the subendothelial space, while the
potential space between the GBM and the podocytes is proteinuria, suggesting that these layers also make muscle cells and stain positive for smooth muscle actin
known as the subepithelial space. important contributions. and myosin. These cells can contract in response to
ADDITIONAL CELL TYPES various signals, narrowing the capillary loops and
The podocytes are large cells with prominent nuclei The mesangial cells provide structural support to the reducing glomerular flow. Signals that modulate
and other intracellular organelles. Their cytoplasm is glomerular capillaries. These cells are irregularly mesangial tone include angiotensin II (see Plate 3-18),
elaborately drawn out into long processes that give rise shaped and send long cytoplasmic processes between antidiuretic hormone (see Plate 3-17), norepinephrine,
to fingerlike projections known as foot processes (pedi- endothelial cells. They are similar to modified smooth and thromboxane. In addition, mesangial cells are
cels). These foot processes attach to the outer surface of capable of phagocytosing local macromolecules and
the GBM and interdigitate with those from adjacent immune complexes, as well as generating inflammatory
podocytes. They also lie between the podocyte cell
bodies and the GBM, forming a subpodocyte space. The
space between adjacent foot processes is generally about
25 to 60 nm. A structure known as the slit diaphragm
spans this distance. It consists of an 11 nm-wide central
filament attached to adjacent podocyte cell membranes
by cross-bridging proteins arranged in a zipper-like
configuration. The pores formed between the central
filament, cell membranes, and cross-bridges have been
measured as approximately 4 × 14 nm. These small
pores in the slit diaphragm make a critical contribution
to the size-based filtration barrier. In addition, the
podocytes are lined by a negatively-charged glycocalyx,
which likely contributes to the charge-based barrier.

The relative contributions of the three layers of the
capillary wall to the filtration barrier remain controver-
sial. The slit diaphragm is likely the main obstacle to
protein diffusion. Indeed, glomerular diseases that
cause loss of protein into the urine (proteinuria) gener-
ally cause a process known as foot process effacement,
in which foot processes retract and shorten, disrupting
slit diaphragms and opening a wide space for the
passage of proteins. Nonetheless, disruption of the
endothelial layer or GBM has also been shown to cause

22 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-22 Anatomy of the Urinary Tract

ELECTRON MICROSCOPY OF THE GLOMERULUS

Parietal epithelial cell
Bowman’s space
Capillary lumen
Podocyte (visceral
epithelial cell)
Endothelial cell
Mesangial cells
and matrix
Podocyte (visceral
epithelial cell)
Endothelial cell
Mesangial cell
Afferent arteriole
Efferent arteriole

Granular cell
Macula densa

GLOMERULUS (Continued) ؋ 1100

mediators in response. The mesangial cells are embed- Golgi complex Mitochondria MPiotodcohcoytnedria
ded in the mesangial matrix, which contains collagen, Bowman’s space
various proteoglycans, and other molecules. In histo- Rough enodpolpalsamsmicic
logic sections of normal glomeruli, one or two mesan- reticulum Foot
gial cells are typically seen per matrix area, with a processes
greater number seen in certain pathologic states.

The parietal epithelial cells are flat squamous cells
with sparse organelles. They are continuous with the
visceral epithelial cells near the base of the glomerular
capillary tuft and with the cells of the proximal tubule
at the opposite side of the glomerulus. In histologic
sections of normal glomeruli, one or two layers of pari-
etal epithelial cells may be seen. In severe, rapidly pro-
gressive glomerular disease, additional layers of parietal
cells may be seen.

THE JUXTAGLOMERULAR APPARATUS Glomerular basement membrane Capillary lumen Endcothelial fenestrations 1 µm

The juxtaglomerular apparatus is a specialized structure Fine details of capillary wall. Reprinted with permission from Ovalle W, Nahirney P. Netter’s Essential
that consists of components from both the glomerulus Histology. Philadelphia, Saunders, 2008.
and the distal tubule of its associated nephron.
known as granular cells, in the walls of the afferent and The granular cells are similar to ordinary smooth
The glomerular components include the terminal efferent arterioles. (For details, see Plate 3-18.) muscle cells but have sparser smooth muscle myosin
afferent arteriole, initial efferent arteriole, and extraglo- and contain numerous renin-filled vesicles. Because
merular mesangium (also known as the lacis or as the The extraglomerular mesangial cells are continuous they produce large quantities of hormones, these cells
cells of Goormaghtigh). The nephron supplied by this with and resemble normal mesangial cells. They are also feature a prominent endoplasmic reticulum and
glomerulus loops around so that its thick ascending linked to the granular cells via gap junctions, and they Golgi apparatus.
limb contacts the extraglomerular mesangium. The share a basement membrane and interstitium with the
region of the thick ascending limb that makes direct adjacent macula densa cells. Thus the extraglomerular Finally, the macula densa cells appear distinct from
contact with the extraglomerular mesangium contains mesangium appears to serve as the signaling intermedi- the neighboring tubular cells; a detailed description is
specialized cells and is known as the macula densa. ary between the tubular and vascular components of the available on Plate 1-25.
juxtaglomerular apparatus.
Because of this arrangement, the distal tubule is able
to provide feedback to the glomerulus to modulate the
filtration rate. In the setting of inadequate tubular flow,
for example, the macula densa triggers dilation of the
afferent arteriole, which increases the filtration rate,
and stimulates renin secretion from specialized cells,

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 23

Plate 1-23 Urinary System: VOLUME 5

Electron microscopy Proximal tubular epithelium
Tubular basement
Tubular Microvilli Brush border filling the membrane
basement Nucleus proximal tubular lumen Collecting duct
membrane
Vesicles

Mitochondria Rough endoplasmic reticulum

From Ovalle W, Nahirney P. Netter’s Vesicle
Essential Histology. Philadelphia, Golgi apparatus
Saunders, 2008, page 365.

Microvilli Nucleus
(brush
border) Cell margins
interdigitating

Tubular base-
ment membrane

PAS stain

Basal infoldings Junctional
Basal process complex
Mitochondria
Ribosomes

Lysosome

Cell borders

Intercellular
space
Basal infolding
and process
from adjacent
cell

Stereogram of proximal convoluted tubular epithelium

PROXIMAL TUBULE microvillous brush border on the apical plasma mem- some molecules to be reabsorbed through a paracellular
brane projects into the lumen and dramatically increases route.
The proximal tubule receives urine from Bowman’s the available surface area for solute transport. On light
space. It plays a major role in the transport of material microscopy, the lumen often appears collapsed or indis- PCT cells are rich with mitochondria, which provide
from the urine back into the blood (reabsorption) and tinct owing to the presence of the brush border, which energy for solute transport. These are arranged perpen-
vice versa (secretion). In humans, the entire proximal should be readily seen. Distal tubules and collecting dicular to the cell base and resemble vertical striations
tubule is approximately 14 mm long. It is divided into ducts, in contrast, lack a brush border and thus appear on some histologic sections. These cells also possess a
two sections: the proximal convoluted tubule (pars con- more widely patent. prominent rough endoplasmic reticulum and Golgi
voluta) and the proximal straight tubule (pars recta). apparatus near the apical membrane.
The latter forms the first part of the loop of Henle. The lateral and basal borders of PCT cells are thrown
into extensive processes that interdigitate with infold- PCT cells contain evidence of extensive endocytosis
In rats, the proximal tubule is often subdivided into ings of adjoining cells; as a result, lateral cell borders near the apical plasma membrane, including coated pits,
S1 (first two thirds of the convoluted part), S2 (last third are indistinct on light microscopy sections. These baso- invaginations, and endosomes. Numerous lysosomes
of the convoluted part and initial portion of the straight lateral processes increase the surface area available for are also present to process and degrade a subset of the
part), and S3 (remainder of the straight part); however, transport across the basolateral cell membrane. They incoming material. Endocytosis appears to be most
these distinctions are generally not made in humans. are replete with additional mitochondria to support important for the reabsorption of filtered proteins, as it
active transport processes. The complex extracellular is up-regulated in conditions that damage the normal
The proximal tubule contains cuboidal to low colum- area between these folds is known as the basolateral glomerular filtration barrier.
nar cells arranged over a tubular basement membrane. intercellular space. It is closed by the tubular basement
These cells possess an eosinophilic cytoplasm, and their membrane, which separates the tubular epithelium PROXIMAL STRAIGHT TUBULE
round nuclei are usually situated near the cell base. from the interstitium and peritubular capillaries.
Their other histologic features differ according to the The cells of the proximal straight tubule differ from
particular region under consideration. Junctional complexes connect neighboring cells near those of the PCT in several important respects. The
their apical surface. These consist of a tight junction microvilli are shorter and sparser, endocytotic figures are
PROXIMAL CONVOLUTED TUBULE (zonula occludens) and an intermediate junction (zonula less frequent, mitochondria are sparser, and the basolat-
adherens). Although tight junctions are critical for eral processes and infoldings are smaller and less elabo-
The proximal convoluted tubule (PCT) is the major site maintaining the barrier between the tubular lumen and rate. These morphologic differences reflect the smaller
of solute reabsorption in the nephron. An extensive interstitium, a small number of discontinuities permits amount of reabsorption that occurs across these cells.

24 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS

Plate 1-24 Stereogram of thin limb epithelium Anatomy of the Urinary Tract
Distribution of thin limb cell types in several mammals Mitochondrion
Nucleus
Subcapsular zone Type II epithelium Golgi apparatus

Renal cortex Microvilli

Outer stripe stripe Intercellular space

Outer zone Type Junctional complexes
I
Inner Type II

Renal medulla (pyramid) Type Tubular basement membrane
IV Cell plasma membrane

Inner zone Type III Thick ascending limb
Thin limb

Vasa recta

Thick
ascending
limb

Venulae
recta

Thin limb

Light microscopy: section through Electron microscopy: section
renal medulla (H&E stain, ϫ680) through renal medulla (ϫ4000)

THIN LIMB inner zones of the medulla. Thus, although both Type II cells are seen in the descending thin limb in
nephron types feature a descending thin limb, only jux- the outer zone of the medulla. They are taller than type
The thin limb receives urine from the proximal straight tamedullary nephrons feature an ascending thin limb. I cells, with more numerous microvilli and basolateral
tubule and also contributes to the loop of Henle. It interdigitations. In addition, the tight junctions are
contains descending and ascending parts, which are Four morphologically distinct types of cells have single-stranded and thus somewhat leaky, permitting
both key components of the countercurrent multiplica- been described in thin limbs of several mammals, and paracellular transport. Of the four cell types, type II
tion system that promotes concentration of urine each cell type appears to have its own physiologic sig- cells show the most interspecies variation.
(details on Plate 3-12). nificance (discussed on Plate 3-15). It is unclear if these
same cell types exist in humans. Type III cells are seen in the descending thin limb in
The transition from the proximal straight tubule to the inner zone of the medulla. These cells are shorter
the thin limb involves a sharp change from cuboidal and TYPE I CELLS than type II cells, with fewer microvilli and interdigita-
low columnar cells to simple, largely flat epithelium. It tions. Their tight junctions are well-developed, restrict-
occurs at the border of the outer and inner stripes of Type I cells are found throughout the descending thin ing paracellular transport.
the outer medulla. limbs of short-looped nephrons. They are short, with
few microvilli or basolateral interdigitations, as well as Type IV cells are seen just before the hairpin turn of
The length of the thin segment differs depending on scant mitochondria or other organelles. Their nuclei the descending thin limb and are present for the
nephron type. In short-looped nephrons, the descend- bulge into the tubular lumen. Neighboring cells are remainder of the ascending thin limb. These cells are
ing thin limb reaches the border of the outer and inner joined by multistranded tight junctions and desmo- completely flattened and have no microvilli, like type I
zones of the medulla and then transitions to the thick somes, which restrict paracellular transport. epithelium, but they have an increased number of baso-
ascending limb. Meanwhile, in long-looped nephrons, lateral interdigitations. Their tight junctions are leaky,
the descending thin limb continues deep into the inner TYPE II-IV CELLS permitting paracellular transport.
zone of the medulla, makes a hairpin turn, becomes the
ascending thin limb, and then transitions to the thick Type II-IV cells are found in the thin limbs of long-
ascending limb at the border between the outer and looped nephrons.

THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS 25

Plate 1-25 Urinary System: VOLUME 5

Stereogram of distal convoluted tubular epithelium

Tubular basement membrane

DISTAL TUBULE Basal infoldings of cell
plasma membrane

Mitochondria

The distal tubule receives urine from the thin limb. Rough endoplasmic reticulum
Like the proximal tubule, the distal tubule is divided Ribosomes
into two major sections. The first is known as the thick Nucleus
ascending limb (also known as the distal straight tubule, Golgi apparatus
or pars recta), and the second is known as the distal Vesicles
convoluted tubule (pars convoluta). Just before the Intercellular space
transition to the distal convoluted tubule, the thick Cell membrane
ascending limb touches its parent glomerulus, and the Junctional complex
epithelial cells that make direct contact constitute a
specialized structure known as the macula densa.

In short-looped nephrons, the thick ascending limb
accounts for the entire ascending limb of the loop of
Henle. In contrast, in long-looped nephrons, the thin
limb accounts for the initial part of the ascending limb,
then transitions to the thick ascending limb at the
border of the inner and outer zones of the medulla.

THICK ASCENDING LIMB Microvilli

The thick ascending limb (TAL) plays an important Distal tubules
role in the reabsorption of ions and is crucial for main-
tenance of the countercurrent multiplication system, shared basement membrane, reflecting their physio- Collecting duct
described on Plate 3-12. logic connection.
Proximal tubules, with
The cells of the TAL are low cuboidal. Their height DISTAL CONVOLUTED TUBULE brush borders projecting
decreases as the tubule progresses from medulla to into lumina
cortex. Their apical surfaces are dotted with sparse, At some distance after the macula densa, there is an
short microvilli. In the rat, there is a subset of “rough” abrupt transition from the low cuboidal cells of the H&E stain
cells, which have sparse microvilli, and “smooth cells,” TAL to the taller cuboidal cells of the distal convoluted
which lack them altogether. The relative proportion of tubule, which takes a tortuous course through a small CONNECTING SEGMENT
“rough” cells increases as the tubules approach the renal area of cortex. The cells of the distal convoluted tubule At the end of the distal tubule, just before the transition
cortex. Because of the scarcity of microvilli, the distal have more numerous apical microvilli than those of the to the collecting duct, there is a zone known as the
tubules appear patent on light microscopy, facilitating TAL, but their other features are similar. connecting segment (or tubule). This segment lacks
the distinction from proximal tubules, which possess a clear boundaries and mixes gradually with the previous
well-developed brush border. and next segments. In general, however, the cells in this
segment have less prominent interdigitating membrane
Below the apical surface are numerous small vesicles, processes and fewer mitochondria than those of the
which traffic ion channels and transporters to the DCT. Principal and intercalated cells, which figure
plasma membrane. The rough endoplasmic reticulum prominently in the collecting duct, begin to appear in
and Golgi apparatus, which synthesize these proteins, this segment.
are prominent. The nuclei are located near the apical
membrane and sometimes bulge out toward the lumen.

The basolateral membranes are thrown into exten-
sive, interdigitating processes and infoldings, which
increase the surface area available for basolateral trans-
port. As a result of this configuration, the lateral cell
borders appear indistinct on light microscopy sections.
The basolateral processes are filled with mitochondria,
which resemble striations on histologic sections, to
provide energy for active transport. Interdigitating pro-
cesses and infoldings from neighboring cells are joined
together by tight junctions.

MACULA DENSA

Unlike the rest of the distal tubular cells, the macula
densa cells are columnar and lack extensive interdigitat-
ing basolateral processes. Their high nucleus to cyto-
plasmic ratio causes them to appear denser than
neighboring cells. Their nuclei are positioned near
their apical surface, above most of the cellular organ-
elles. The basal surfaces of these cells interdigate with
the adjacent extraglomerular mesangium through their

26 THE NETTER COLLECTION OF MEDICAL ILLUSTRATIONS