Netter's Concise Orthopaedic Anatomy 2nd Edition

5 Forearm • TOPOGRAPHIC ANATOMY

Anterior view

Posterior view

Cephalic vein

Median cubital vein Basilic vein

Brachioradialis muscle

Flexor carpi Flexor/pronator
radialis tendon
Thenar mass
eminence
Palmaris Brachioradialis
1 longus and extensor
tendon carpi radialis
longus muscles

Flexor digitorum Mobile wad
superficialis
tendons

2 Flexor carpi Extensor carpi Olecranon of ulna
3 45 ulnaris tendon radialis brevis Radial head
muscle Flexor carpi ulnaris muscle
Extensor carpi ulnaris muscle
Anatomic snuffbox

Extensor pollicis
longus tendon

Extensor indicis 1 Cephalic vein
tendon Lister’s tubercle

Ulnar styloid
2 Extensor digitorum tendons

3
45

STRUCTURE CLINICAL APPLICATION
Olecranon Proximal tip of ulna. Tenderness can indicate fracture.
Radial head Proximal end of radius. Tenderness can indicate fracture.
Flexor radialis tendon Landmark for volar approach to wrist. Radial pulse is just radial to tendon.
Lister’s tubercle Tubercle on dorsal radius. “Lighthouse of the wrist.” EPL tendon runs around it.
Ulnar styloid Prominent distal end of ulna. Tenderness can indicate fracture.
Palmaris longus tendon Not present in all people. Can be used for tendon grafts.
Anatomic snuffbox Site of scaphoid. Tenderness can indicate a scaphoid fracture.

140 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Right radius and ulna in Olecranon OSTEOLOGY • Forearm 5
supination: anterior view Trochlear notch
Coronoid process Right radius and ulna in
Head Radial notch of ulna pronation: anterior view

Neck Ulnar tuberosity Oblique cord
Radial tuberosity Ulnar tuberosity
Oblique cord
Ulna
Radius Ulna Radius
Lateral surface
Anterior surface Anterior surface Posterior border
Posterior surface
Anterior border Anterior border
Interosseous border Dorsal (Lister’s) tubercle
Interosseous membrane Groove for extensor
Interosseous Interosseous border carpi radialis longus
membrane and brevis muscles
Groove for extensor
pollicis longus muscle Area for extensor pollicis
brevis and abductor pollicis
Groove for extensor longus muscles
digitorum and extensor Styloid process
indicis muscles

Styloid process

Ulnar (sigmoid) notch Styloid process
of ulna

Radius Ulna

Styloid Styloid process Coronal section of radius
process demonstrates how thickness
Lunate facet of cortical bone of shaft
Scaphoid facet Carpal articular suface diminishes to thin layer over
cancellous bone at distal end

CHARACTERISTICS OSSIFY FUSE COMMENTS

• Cylindrical long bone RADIUS • Anterolateral portion of RH has less sub-
• Head is intraarticular chondral bone (susceptible to fracture)
• Tuberosity: biceps inserts Primary 8-9wk 14yr
• Shaft has a bow Shaft 2-3yr • Tuberosity points ulnarly in supination
• Distal end widens, is made Secondary 4yr 16-18yr • Bow allows rotation around ulna
Head 16-18yr • Cancellous distal radius common fracture
of cancellous bone, has Distal
scaphoid & lunate facets, epiphysis site (esp. in peds & older pts)
& radial styloid • Distal radius x-ray measurements: 11°
• Ulnar (sigmoid) notch: DRUJ Primary ULNA
Shaft 8-9wk 16-18yr volar tilt, 22° radial inclination, 11-12mm
• Long bone: straight bone radial height
• Triangular cross-section Secondary 9yr 16-20yr
• Tuberosity: brachialis Olecranon 5-6yr 16-20yr • The radius rotates around the stationary
Distal ulna through proximal & distal notches
insertion epiphysis during pronation/supination
• Proximal: olecranon, coro-
• 75% of growth from distal epiphysis
noid process, radial • Olecranon & coronoid provide primary
(sigmoid) notch
• Distal: ulnar styloid bony stability to elbow joint
• Coronoid fx can result in instability
• Common site of fx (often w/DR fx)

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 141

5 Forearm • OSTEOLOGY

Metacarpal bones Metacarpal bones

43 2 23 4

5 11 5

Capitate Trapezoid
Hook of
hamate Tubercle of Capitate
Hamate trapezium Trapezoid
Pisiform Hamate
Triquetrum Trapezium
Triquetrum
Lunate Tubercle of Trapezium
Ulnar scaphoid Radial styloid Pisiform
styloid Scaphoid process Lunate
process
Radial styloid Scaphoid Ulnar
Ulna process styloid
Dorsal tubercle process
Anterior (palmar) view Radius (Lister’s) of the radius

Ulnar (sigmoid) Radius Ulna
notch

Posterior (dorsal) view

CHARACTERISTICS OSSIFY FUSE COMMENTS

PROXIMAL ROW

Scaphoid: boat shape, 80% covered 5th 5yr 14-16yr • Blood supply enters dorsal waist,
with articular cartilage (not waist) bridges both rows

• #1 carpal fx. Proximal fractures are
at risk of nonunion/AVN

Lunate: moon shape. Four articulations: 4th 4yr 14-16yr • Dislocations: rare but often missed
1. radius (lunate facet), 2. scaphoid, • Will rotate (carpal instability) if liga-
3. triquetrum, 4. capitate
mentous attachments to adjacent
bones are disrupted

Triquetrum: pyramid shape. Lies 3rd 3yr 14-16yr • 3rd most common carpal fracture
under the pisiform and ulnar styloid • Articulates with TFCC

Pisiform: large sesamoid bone. 8th 9-10yr 14-16yr • Multiple attachments: FCU, transverse
In FCU tendon, anterolateral to carpal ligament (TCL), abductor digiti
triquetrum minimi, multiple ligaments

DISTAL ROW

Trapezium: saddle shape 6th 5-6yr 14-16yr • Has groove for FCR tendon

Trapezoid: trapezoidal/wedge shape 7th 6-7yr 14-16yr • Articulates with second metacarpal

Capitate: largest carpal bone, 1st carpal 1st 1yr 14-16yr • Keystone to carpal arch, floor of CT
bone to ossify • Retrograde blood supply

Hamate: has volar-oriented hook that is 2nd 2yr 14-16yr • Hook can fx, ulnar a. can be injured
distal and radial to pisiform • TCL attaches border of Guyon’s canal

• Ossification: each from a single center in a counter-clockwise direction (anatomic position) starting with the capitate.
• Each bone has multiple (4-7) tight articulations with adjacent bones.
• Proximal row is considered the “intercalated segment” between the distal radius/TFCC and distal carpal row.
• Scaphoid-lunate angle (measured on lateral x-ray): avg. 47° (range 30-60°; Ͻ30ϭVISI, Ͼ60ϭDISI).

142 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

RADIOLOGY • Forearm 5

Capitate Hook of
Scaphoid hamate
Scapho- Triquetrum
lunate
interval Pisiform Distal Capitate
Lunate pole of Lunate
Distal Ulnar scaphoid
radius styloid Ulna
Pisiform
Trapezium Ulna
Radius
Scaphoid
Wrist x-ray, AP Wrist x-ray, lateral
Distal
radius Capitate Hamate
Scaphoid
Triquetrum Hook of
Lunate hamate
Ulna
Lunate Pisiform
Triquetrum

Wrist x-ray, oblique Wrist x-ray, ulnar deviation

RADIOGRAPH TECHNIQUE FINDINGS CLINICAL APPLICATION
AP (anteroposterior)
Lateral Palm down on plate, beam Carpal bones, radiocarpal joint Distal radius, ulnar, carpal
Oblique
AP-ulnar deviation perpendicular to plate fractures or dislocation
Carpal tunnel view
Ulnar border of wrist & Alignment of bones, joints Same as above, carpal
CT hand on plate (lunate) instability
MRI
Lateral with 40° rotation Alignment & position of bones Same as above
Bone scan
AP, deviate wrist ulnarly Isolates scaphoid Scaphoid fractures

Maximal wrist extension, Hamate, pisiform, trapezium Fractures (esp. hook of the
beam at 15° hamate)

OTHER STUDIES

Axial, coronal, & sagittal Articular congruity, bone heal- Fractures (scaphoid, hook
ing, bone alignment of hamate), nonunions

Sequence protocols vary Soft tissues (ligaments, tendons, Occult fractures

cartilage), bones (e.g., scaphoid), tears

(e.g., TFCC, S-L ligament)

All bones evaluated Infection, stress fxs, tumors

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 143

5 Forearm • TRAUMA

Fracture of Both Forearm Bones

Fracture of both radius and ulna with angulation, shortening, and comminution of radius

Open reduction and fixation with compression plates and screws through both cortices. Good alignment,
with restoration of radial bow and interosseous space.

Preoperative radiograph.
Fractures of shafts of both
forearm bones

Postoperative radiograph.
Compression plates applied
and fragments in good
alignment

DESCRIPTION EVALUATION CLASSIFICATION TREATMENT

RADIUS AND ULNA FRACTURES

Both-Bone Fracture

• Mech: fall or high energy Hx: Trauma, pain and Descriptive: • Peds (Ͻ10-12y.o.):
• Both bones usually frac- swelling, ϩ/Ϫ deformity • Proximal, middle, distal 1⁄3 closed reduction
PE: Swelling, tenderness, ϩ/Ϫ • Displaced/angulated and casting
ture as energy passes clinical deformity • Comminuted
thru both bones XR: AP & lateral forearm • Open or closed • Adults: ORIF (plates
• Fractures can be at dif- & screws) through
ferent levels separate incisions

COMPLICATIONS: Malunion (loss of radial bow leads to decreased pronosupination), decreased range of motion

Single-Bone Fracture

• Mechanism: direct blow; Hx: Direct blow to forearm Descriptive: • Nondisplaced: cast
aka “nightstick fracture” PE: Swelling, tenderness • Displaced, shortened, an- • Displaced: ORIF
XR: AP & lateral forearm
• Ulna most common gulated, comminuted

COMPLICATIONS: Nonunion, malunion

144 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Monteggia Fracture TRAUMA • Forearm 5

In less common type of Monteggia Fractures of proximal
fracture, ulna angulated posteriorly ulna often characterized
and radial head dislocated posteriorly by anterior angulation
of ulna and anterior
Galeazzi Fracture dislocation of radial head

with

C.A. Luce

Anteroposterior view of fracture of radius Dislocation of distal radioulnar joint
plus dislocation of distal radioulnar joint better demonstrated in lateral view

DESCRIPTION EVALUATION CLASSIFICATION TREATMENT

MONTEGGIA FRACTURE

• Proximal ulna fracture, Hx: Fall, pain and swelling Bado (based on RH location): • Ulna: ORIF (plate/screws)
shortening forces result PE: Tenderness, deformity. • I: Anterior (common) • Radial head: closed re-
in radial head dislocation Check compartments and • II: Posterior
do neurovascular exam • III: Lateral duction (open if irreduc-
• Mechanism: direct blow XR: AP/lateral: forearm; • IV: Anterior with associ- ible or unstable)
or fall on outstretched also, wrist and elbow • Peds: closed reduction
hand ated both-bone fracture and cast

COMPLICATIONS: Radial nerve/PIN injury (most resolve), decreased ROM, compartment syndrome, nonunion

GALEAZZI FRACTURE

• Mechanism: fall on out- Hx: Fall, pain and swelling By mechanism: • Radius: ORIF
stretched hand PE: Tenderness, deformity. • Pronation: Galeazzi • DRUJ: closed reduction,
Check compartments and • Supination: Reverse
• Distal 1⁄3 radial shaft do neurovascular exam ϩ/Ϫ percutaneous pins
fracture, shortening XR: AP/lateral forearm: Galeazzi (ulna shaft fx with in supination if unstable
forces result in distal ra- ulna usually dorsal. Also, DRUJ dislocation) (open if unstable)
dioulnar dislocation wrist and elbow series • Cast for 4-6wk
• Peds: reduce & cast

COMPLICATIONS: Nerve injury, decreased ROM, nonunion, DRUJ arthrosis

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 145

5 Forearm • TRAUMA

Frykman Classification of Fractures of Distal Radius

IV VI
II
VIII

I III V

VII

Extraarticular radius: I Radiocarpal intraarticular: III Intraarticular distal Intraarticular radiocarpal
Ulnar styloid: II Ulnar styloid: IV radioulnar: V and distal radioulnar: VII
Ulnar styloid: VI Ulnar styloid: VIII

Reduction of a Colles Fracture

Fractures can usually be reduced by
closed manipulation. Wrist first
dorsiflexed; traction initiated as distal
and volar thumb pressure applied
over distal fragments

With pressure and traction maintained, wrist gently straightened

DESCRIPTION EVALUATION CLASSIFICATION TREATMENT

DISTAL RADIUS FRACTURE • Nondisplaced: cast
• Displaced:
• Mechanism: fall on out- Hx: Trauma (usually fall), Frykman (for Colles):
stretched hand pain and swelling • Type I, II: extraarticular ‫ ؠ‬Stable: closed
PE: Swelling, tenderness, • Type III, IV: RC joint reduction, well-
• Very common (Colles #1) ϩ/Ϫ deformity. Do thor- • Type V, VI: RC joint molded cast, 4-6wk
• Cancellous bone susceptible ough neurovascular • Type VII, VIII: both radio-
exam. ‫ ؠ‬Unstable: closed
to fx (incl. osteoporotic fx) XR: Wrist series (3 views) ulnar & radiocarpal reduction, percuta-
• Colles (#1): dorsal displace- Normal measurements (RC) joints involved neous pinning ϩ/Ϫ
‫ ؠ‬11° volar tilt • Even # fxs have associ- ext. fix. or ORIF
ment (apex volar angulation) ‫ ؠ‬11-12mm radial ated ulnar styloid fx
• Smith fx: volar displacement Other fxs, descriptive: • Intraarticular: ORIF
• Barton fx: articular rim fx height displaced, angulated (e.g., volar plate)
• Radial styloid (“chauffeur fx”) ‫ ؠ‬23º radial inclination
CT: For intraarticular fxs • Elderly: cast, early ROM

COMPLICATIONS: Malunion, posttraumatic osteoarthritis, stiffness/loss of range of motion

146 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

with TRAUMA • Forearm 5

C.A. Luce Scaphoid Fracture
Less common fractures
Fracture of middle
third (waist) of Tubercle Distal pole
scaphoid (most
common) Vertical shear Proximal pole
Perilunate Dislocation

Palmar view shows (A) lunate C Capitate Lateral view shows lunate
rotated and displaced volarly, A displaced volarly and rotated.
(B) scapholunate space widened, Tuberosity Broken line indicates further
(C) capitate displaced proximally B of scaphoid dislocation to volar aspect of
and dorsally distal radius
Lunate

DESCRIPTION EVALUATION CLASSIFICATION TREATMENT

SCAPHOID FRACTURE

• Mechanism: fall on out- Hx: Trauma (usually Location: • Nondisplaced: 1. Cast-
stretched hand fall), pain and swelling • Proximal pole ing (LAC & SAC) aver-
PE: “Snuffbox” tender- • Middle/”waist” (#1) age 10-12wk;
• Most common carpal fx ness, decreased ROM • Distal pole 2. Percutaneous screw
• Retrograde blood suppy XR: Wrist & ulnar devia-
tion views Position: • Displaced: ORIF ϩ/Ϫ
to proximal pole is in- CT: For most fxs; shows • Displaced bone graft
jured in waist fxs, can displacement/pattern • Angulated/shortened
lead to nonunion or AVN MR: Occult fx, AVN • Nonunion: ORIF with
• Distal pole usually heals tricortical bone graft or
• High index of suspicion vascularized bone
will decrease missed fxs graft

COMPLICATIONS: Nonunion, wrist arthrosis (SLAC wrist from chronic nonunion), osteonecrosis (esp. proximal pole)

PERILUNATE INSTABILITY/DISLOCATION

• Mech: fall; axial compres- Hx: Trauma/fall, pain Instability (Mayfield (4)) • Instability: closed vs
sion & hyperextension PE: Characteristic volar • I: Scapholunate disruption open reduction, percu-
“fullness”, decr. ROM • II: Lunocapitate disruption taneous pinning & pri-
• Instability progresses XR: S-L gap Ͼ3mm • III: Lunotriquetral disruption mary ligament repair
through 4 stages (May- S-L angle: Ͼ60º or • IV: Lunate (peri) dislocation
field) as various liga- Ͻ30º Dislocation (Stage 4 instability) • Dislocation: open re-
ments are disrupted CT: Evaluate carpal fxs • Lesser arc: ligaments only duction of lunate, per-
MR: Shows ligament in- • Greater arc: assoc. carpal fx cutaneous pinning
• Dislocation (stage 4) oc- jury in subtle early ϩ/Ϫ ORIF of carpal fx
curs through weak spot stages
(space of Poirier) • Late/wrist arthrosis:
proximal row carpec-
• Transscaphoid disloca- tomy or STT fusion
tion is #1 injury pattern

COMPLICATIONS: Wrist arthrosis (e.g., SLAC from instability), nonunion of fracture, chronic pain and/or instability

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 147

5 Forearm • TRAUMA

Torus (buckle)
fracture of radius

Greenstick fractures
of radius and ulna

DESCRIPTION EVALUATION CLASSIFICATION TREATMENT

INCOMPLETE FRACTURE: TORUS AND GREENSTICK FRACTURE • Torus: reduction rarely
needed, cast 2-4wk
• Common in children (usually Hx: Trauma, pain, inability/ • Torus (buckle): concave
3-12y.o.) unwilling to use hand/ cortex compresses • Greenstick: nondis-
extremity (buckles), convex/ placed—SAC 2-4wk.
• Mechanism: fall on out- PE: ϩ/Ϫ deformity. Point tension side: intact Reduce if Ͼ10º of
stretched hand most common tenderness & swelling angulation—well-
XR: AP and lateral. Torus: • Greenstick: concave, molded LAC 3-4wk
• Distal radius most common cortical “buckle.” Green- cortex intact or buck-
• Increased elasticity of pediat- stick: unicortical fracture led, convex/ tension
side fracture or plastic
ric bone allows for plastic de- deformity
formity and/or unicortical fx

COMPLICATIONS: Deformity, malunion, neurovascular injury (rare)

148 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

JOINTS • Forearm 5

Radius Radius Wrist (radiocarpal) joint
Midcarpal joint
Wrist Carpometacarpal joint
(radiocarpal) Palm
joint
Wrist (radiocarpal) joint
Articular disc Hand in Midcarpal joint
of wrist joint flexion

Lunate

Midcarpal
joint

Capitate

Carpometacarpal
joint

3rd metacarpal bone

Dorsum Palm Carpometacarpal joint

Hand in Hand in
anatomical extension
position

Sagittal sections through wrist and Palm
middle finger

WRIST

GENERAL

• The wrist is a complex joint comprising 3 main articulations: 1. Radiocarpal (distal radius/TFCC to proximal row),
2. Distal radioulnar joint (DRUJ), 3. Midcarpal (between carpal rows)

• Other articulations: pisotriquetral and multiple intercarpal (between 2 adjacent bones in the same row)
• Proximal row has no muscular attachments, considered the “intercalated segment,” & responds to transmitted forces.

Distal row bones are tightly connected and act as a single unit in a normal wrist.
• Range of motion:

‫ ؠ‬Flexion 65-80° (40% from radiocarpal, 60% midcarpal); extension 55-75° (65% radiocarpal, 35% midcarpal)
‫ ؠ‬Radial deviation: 15-25°; ulnar deviation: 30-45° (55% midcarpal, 45% radiocarpal)
• Types of ligaments
‫ ؠ‬Extrinsic: connect the distal forearm (radius & ulna) to the carpus
‫ ؠ‬Intrinsic: connect carpal bones to each other (i.e., origin and insertion of ligament both within the carpus)

‫ ؠ‬Interosseous: ligaments connecting carpal bones within the same row (proximal or distal)
‫ ؠ‬Midcarpal/Intercarpal: ligaments connecting carpal bones between the proximal and distal rows.
• Palmar (volar) ligaments are stronger and more developed; most are intracapsular.

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 149

5 Forearm • JOINTS Short radiolunate ligament
Palmar radioulnar ligament
Flexor retinaculum removed: Ulnolunate ligament
palmar view Ulnocapitate ligament
Ulnotriquetral ligament
Long radiolunate ligament Lunotriquetral ligament
Space of Poirier Triquetrohamate ligament
Triquetrocapitate ligament
Radioscaphocapitate ligament
Scaphotrapeziotrapezoid ligament Capitohamate ligament
5
Scaphocapitate ligment
Trapeziotrapezoid ligament

Trapeziocapitate ligament 1

2 34
Metacarpal bones

LIGAMENTS ATTACHMENTS FUNCTION/COMMENT

RADIOCARPAL JOINT

Extrinsic—Palmar

Superficial

Radioscaphocapitate Radius to carpus Blends with UC to form distal border of space of Poirier
‫ ؠ‬Radioscaphoid (RS) Radial styloid to scaphoid Aka “radial collateral” lig. Stabilizes proximal pole
‫ ؠ‬Radiocapitate (RC) Radius to capitate body Forms a fulcrum around which the scaphoid rotates

Long radiolunate (lRL) Volar radius to lunate Blends with palmar LT interosseous ligament

Ulnocapitate (UC) Ulna/TFC to capitate Blends with RSC laterally. Distal border of space of
Short radiolunate (sRL) Distal radius to lunate Poirier

Deep

Stout & vertical. Prevents dx in hyperextension

Ulnolunate (UL) TFC to lunate UL & UT blend with UC to help stabilize the DRUJ

Ulnotriquetral (UT) TFC to triquetrum UL & UT considered by some to be part of the TFCC

Radioscapholunate Radius to SL joint “Ligament of Testut,” a neurovascular bundle to SL jt.

Dorsal radiocarpal (DRC) Extrinsic—Dorsal
‫ ؠ‬Superficial bundle
‫ ؠ‬Deep bundle Radius to lunate/triquetrum Aka radiolunotriquetral (RLT); main dorsal stabilizer
Radius to triquetrum The two bundles are typically indistinguishable
Radius to LT joint Fibers attach to lunate and/or lunotriquetral ligament

• Space of Poirier: weak spot volarly where perilunate dislocations occur (between the proximal edge of RSC & UC liga-
ments distally and distal edge of lRL ligament proximally).

• No true ulnar collateral ligament exists in the wrist. The ECU & sheath provide some ulnar collateral support.
• Deep volar extrinsic ligaments can be seen easily during wrist arthroscopy; the superficial ones are difficult to visualize.
• The UC, UL, and UT form the ulnocarpal ligamentous complex.

150 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Posterior (dorsal) view JOINTS • Forearm 5

Dorsal radial metaphyseal arcuate ligament Dorsal radiocarpal ligament (DRC)
Dorsal radioulnar ligament Scapholunate dorsal ligament
Trapeziotrapezoid ligament
Ulnotriquetral ligament (dorsal view) Trapeziocapitate ligament
1
Triquetrohamate ligament

Dorsal intercarpal ligament (DIC)
Capitohamate ligament

5

4
32

Metacarpal bones

LIGAMENTS ATTACHMENTS FUNCTION / COMMENT

INTRINSIC LIGAMENTS

Triquetrohamocapitate (THC) Triquetrum to: Midcarpal Joint
‫ ؠ‬Triquetrohamate (TH) Hamate
‫ ؠ‬Triquetrocapitate (TC) Capitate Palmar

Medial/ulnar portion of arcuate ligament
Short, stout ligament
Often confluent with the ulnocapitate part (UC) ligament

Scaphocapitate (SC) Scaphoid to capitate Stabilizes distal scaphoid. Radial part of arcuate lig.
Dorsal intercarpal (DIC)
Dorsal

Triq. to tpzm./tpzd. A primary dorsal support

Scaphotrapeziotrapezoid (STT) Scaph. to tpzm./tpzd. Lateral (radial) and scaphotrapezial joint support

Interosseous Joints

PROXIMAL ROW: 2 joints. Ligaments are “C” shaped with dorsal and palmar limbs and a membranous portion between.
The membrane prevents communication b/w the radiocarpal and midcarpal joints. It does not add stability.
1. Scapholunate (SL) joint: Scaphoid gives a flexion force to the lunate. Arch of motion during ROM: scaphoidϾlunate.
2. Lunotriquetral (LT) joint: Triquetrum provides an extension force to the lunate, which is resisted by the LT.

Scapholunate (SL or SLIL) Scaphoid to lunate Dorsal fibers strongest. Disruption: instability, (DISI)
Palmar fibers are looser & allow scaphoid rotation

Lunotriquetral (LT) Lunate to triquetrum Palmar fibers strongest. Disruption (with DRC ligament in-
jury) leads to carpal instability (VISI)

DISTAL ROW: 3 joints as below. Strong interosseous ligaments keep distal row moving as a single unit.

Trapeziotrapezium Trapezoid to trapezium Each ligament has 3 parts (palmar, dorsal, deep/
Capitotrapezoid Capitate to trapezium interosseous). Distal row ligaments are stronger than in
Capitohamate Capitate to hamate proximal row. CH lig. is strongest distal row ligament.

Pisotriquetral Articulation

Pisohamate Pisiform to hamate Inserts on hook of hamate; part of Guyon’s canal

Pisometacarpal Pisiform to 5th MC base Assists in FCU flexion

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 151

5 Forearm • JOINTS

Carpal tunnel: palmar view

Palmaris longus tendon Radius Ulna Ulna

Palmar carpal ligament Interosseous Palmar
(thickening of deep membrane radioulnar
antebrachial fascia) Ulnar artery ligament
(cut and reflected) and nerve
Flexor carpi
Radial artery ulnaris tendon Ulnolunate Palmar
and superficial part ulno-
palmar branch Flexor digitorum carpal
profundus Ulnotri- ligament
Flexor carpi tendons quetral
radialis tendon Flexor digitorum part
superficialis
Flexor pollicis tendons Flexor carpi ulnaris
longus tendon tendon (cut)
Pisiform
Median nerve Pisiform
Deep palmar
Palmar branch of ulnar Pisometacarpal
aponeurosis artery and deep ligament
branch of ulnar
Tubercle of nerve Pisohamate
scaphoid ligament
Hook of
Tubercle of 5 hamate Hook of hamate
trapezium
Flexor carpi Palmar metacarpal
Transverse 1 radialis insertion 4 5 ligaments
carpal liga-
23 4

ment (flexor

retinaculum) Metacarpal bones

Flexor pollicis longus tendon

Radiocarpal joint

Scapholunate lig. Dorsal scapho-
Wrist MRI, axial lunate ligament

Scaphoid Dorsal Scaphoid

Radioscapho- Lunate Volar
capitate lig. scapho-
Ulnar lunate
Long radio- ligament
lunate lig. Ligament styloid
Scaphoid fossa
(of distal radius) of Testut

Scapholunate ridge (radio- Triquetrum

scapho- Lunate Volar
lunate) Flexor tendons in carpal tunnel

Lunate fossa
(of distal radius)

Triangular fibrocartilage complex

Wrist MRI, coronal

Prestyloid recess Ulnar styloid Triquetrum

Triquetrum ECU sheath Lunate
Ulnotriquetral
lig. Triangular Scaphoid
Palmar distal fibrocartilage
radioulnar lig. (disc) Triangular
fibrocartilage
Ulnolunate Dorsal distal complex
lig. radioulnar lig. Distal radius

Lunate fossa Ulna
(of distal radius)

152 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

JOINTS • Forearm 5

Triquetrum
ECU tendon
Lunate
Meniscus homologue
Ulnotriquetral lig.
Prestyloid recess
Ulnolunate lig.
Palmar radioulnar lig.
Articular disc
Dorsal radioulnar lig.

ECU tendon sheath
Ulna

Radius

LIGAMENTS ATTACHMENTS FUNCTION / COMMENT

DISTAL RADIOULNAR JOINT

• This joint (DRUJ) is stabilized by a combination of structures that form the triangular fibrocartilage complex (TFCC).
• Primary motion is pronation (60-80°) & supination (60-85°); the radius rotates around the stationary ulna.
• 20% of an axial load is transmitted to ulna in an ulnar neutral wrist. The ulna takes more load when it is ulna positive.

Triangular Fibrocartilage Complex

• TFCC is interposed between the distal ulna and the ulnar proximal carpal row (triquetrum). It originates at the articular
margin of the sigmoid notch (radius) and inserts at the base of the ulnar styloid.

• Vascular supply to TFCC (from ulnar artery & anterior interosseous artery) penetrate the peripheral 10%-25%.

Triangular fibrocartilage Radius to ulna fovea (deep fibers) & TFC has 3 portions: central disc and
styloid (superficial fibers) 2 peripheral (radioulnar) ligaments

‫ ؠ‬Central (articular) disc Blends w/ radial articular cartilage Resists compression and tension; avascular
and aneural

‫ ؠ‬Dorsal radioulnar Dorsal radius to ulnar fovea Blends with TFC, tight in pronation, loose in
(ligamentum subcruentum) supination

‫ ؠ‬Palmar radioulnar Volar radius to ulnar fovea Blends with TFC, tight in supination, loose in
(ligamentum subcruentum) pronation

Meniscal homologue Dorsal radius to volar triquetrum Highly vascular synovial fold

ECU tendon sheath Ulna styloid, triquetrum, hamate Considered an “ulnar collateral ligament”

Other

• UL, UT, and prestyloid recess are considered by some to be a part of the TFCC.

Ulnolunate (UL) TFC to lunate UL & UT blend with ulnocapitate lig. to contrib-
Ulnotriquetral (UT) TFC to triquetrum ute to fxn of TFCC and stabilize the DRUJ.

Prestyloid recess None Between palmar radioulnar ligament & menis-
cus homologue

• Other structures contributing to DRUJ stability: ECU, pronator quadratus, interosseous membrane.
• TFCC can be torn (degenerative or traumatic). Peripheral tears can be repaired, central tears need debridement.

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 153

5 Forearm • TUNNELS

Carpal tunnel

Flexor Median n. Ulnar n. in Transverse carpal
tendons Palmar cutaneous Guyon’s canal
branch of median n. lig. (roof of carpal
Transverse Flexor tendons
carpal lig. Thenar mm. in carpal tunnel tunnel) Median n. in
Abductor pollicis brevis
Carpal carpal tunnel
tunnel
Opponens pollicis

Flexor pollicis
brevis (superficial
head)

1st and 2nd lumbrical mm. Ulnar nerve
Ulnar tunnel
Digital nn.
Ulnar tunnel

Volar carpal Transverse Zone I (motor
Palmaris ligament carpal and sensory)
brevis m. ligament
Zone II
Pisiform (motor)
Ulnar n.
Ulnar a. Zone III
(sensory)

STRUCTURE COMPONENTS COMMENTS

CARPAL TUNNEL

Transverse carpal Attachments: • Roof of carpal tunnel, can compress median nerve.
ligament (TCL, Medial: pisiform and hamate TCL is incised in a carpal tunnel release.
flexor retinacu- Lateral: scaphoid and trapezium
lum) • Tunnel is narrowest at hook of hamate

Borders Roof: transverse carpal ligament • See above
Floor: central carpal bones • Especially capitate and trapezoid
Medial wall: pisiform and hamate • Hook of hamate gives medial wall
Lateral wall: trapezium and scaphoid • Trapezium is primary wall structure

Contents Tendons: FDS (4), FDP (4), FPL • 9 tendons within the carpal tunnel
Nerve: median • Compressed in carpal tunnel syndrome

• Thenar motor branch of median nerve can exit under, through, or distal to the transverse carpal ligament.
• A persistent median artery or aberrant muscle can occur in the tunnel and may cause carpal tunnel syndrome.

ULNAR TUNNEL / GUYON’S CANAL

Borders Floor: transverse carpal ligament • Can be released simultaneously with CTR
Roof: volar carpal ligament • Continuous with deep antebrachial fascia
Medial wall: pisiform • Neurovascular bundle is under pisohamate ligament
Lateral wall: hook of hamate • Fracture can cause nerve compression.

Contents Ulnar nerve • Divides in canal to deep & superficial branches
Ulnar artery • Terminates as superficial arch around hamate

• Fractures (malunion) or masses (e.g., ganglion cysts #1) can compress the ulnar nerve or artery within the canal.

154 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

OTHER STRUCTURES • Forearm 5

Posterior (dorsal) Extensor carpi ulnaris— Compartment 6
view
Extensor digiti minimi — Compartment 5
Plane of cross section
shown below Extensor digitorum Compartment 4
Extensor indicis
Extensor retinaculum
Abductor digiti Extensor pollicis longus — Compartment 3
minimi muscle
Extensor carpi radialis brevis Compartment 2
Intertendinous connections Extensor carpi radialis longus
(junctura tendinae)
Abductor pollicis longus Compartment 1
Extensor pollicis brevis

Radial artery in anatomical snuffbox
Dorsal interosseous muscles

Transverse fibers of
extensor expansions (hoods)

Cross section of most distal portion of forearm

Extensor retinaculum

Extensor digitorum and Extensor pollicis longus — Compartment 3
extensor indicis
Compartment 4 Extensor carpi
radialis brevis
Compartment 5 Extensor Compartment 2
digiti minimi Extensor carpi
radialis longus

Extensor 5 4 32 Extensor Compartment 1
Compartment 6 carpi 6 1 pollicis brevis

ulnaris Ulna Radius Abductor
pollicis longus

STRUCTURE FUNCTION COMMENTS

EXTENSOR COMPARTMENTS

Extensor retinaculum Covers the wrist dorsally Forms six fibro-osseous compartments through
which the extensor tendons pass

Number Tendon Clinical Condition

Dorsal compartments I EPB, APL de Quervain’s tenosynovitis can develop here

II ECRL, ECRB Tendinitis can occur here

III EPL Travels around Lister’s tubercle, can rupture

IV EDC, EIP This compartment split in dorsal wrist approach

V EDQ (EDM) Rupture (Jackson-Vaughn syndrome) in RA

VI ECU Tendon can snap over ulnar styloid causing pain

• EIP and EDQ tendons are ulnar to EDC tendons to the index and small fingers, respectively.
• 1st compartment may have multiple slips that all need to be released in de Quervain’s disease for a full release.

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 155

5 Forearm • MINOR PROCEDURES Carpal Tunnel Injection

Wrist Injection

Lister’s Extensor Palmaris longus
tubercle pollicis tendon
longus
tendon Median nerve Ulnar nerve

Extensor Dorsal
carpi radialis branch
longus of ulnar
tendon nerve

Extensor
carpi radialis
brevis
tendon

Superficial
radial nerve

STEPS

WRIST ASPIRATION/INJECTION

1. Ask patient about allergies
2. Palpate radiocarpal joint dorsally, find Lister’s tubercle and the space ulnar to it
3. Prep skin over dorsal wrist (iodine/antiseptic soap)
4. Anesthetize skin locally (quarter size spot)
5. Aspiration: insert 20-gauge needle into space ulnar to Lister’s tubercle/EPL/ECRB and radial to EDC, aspirate.

Injection: insert 22-gauge needle into same space, aspirate to ensure not in vessel, then inject 1-2ml of local
or local/steroid preparation into RC joint.

6. Dress injection site
7. If suspicious for infection, send fluid for Gram stain and culture

CARPAL TUNNEL INJECTION/MEDIAN NERVE BLOCK

1. Ask patient about allergies
2. Ask patient to pinch thumb and small finger tips; palmaris longus (PL) tendon will protrude (10% -20% do not have

one). Median nerve is beneath PL, just ulnar to FCR within the carpal tunnel.
3. Prep skin over volar wrist (iodine/antiseptic soap)
4. Anesthetize skin locally (quarter size spot)
5. Insert 22-gauge or smaller needle into wrist ulnar to PL at flexion crease at 45º angle. Aspirate to ensure needle is

not in a vessel. Inject 1-2ml of local or local/steroid preparation.
6. Dress injection site

WRIST BLOCK

Four separate nerves are blocked. Based on the necessary anesthesia, a complete or partial block can be performed:
1. Ask patient about allergies
2. Prep skin over each landmark (iodine/antiseptic soap)
3. Ulnar nerve: palpate the FCU tendon just proximal to volar wrist crease. Insert needle under the FCU tendon.

Aspirate to ensure needle is not in ulnar artery (nerve is ulnar to the artery). Inject 3-4ml of local anesthetic into
the space dorsal to the FCU tendon.
4. Dorsal cutaneous branch of ulnar nerve: palpate the distal ulna/styloid. Inject a large subcutaneous wheal on the
dorsal and ulnar aspect of the wrist, just proximal to the ulnar styloid.
5. Superficial radial nerve: block at radial styloid with a large subcutaneous wheal on the dorsoradial aspect of
the wrist.
6. Median nerve: block in carpal tunnel as described above
7. Palmar cutaneous branch of median nerve: raise a wheal over the central volar wrist.

• Median and superficial radial nerve blocks are effective for thumb, index finger, and most middle finger injuries.
• Ulnar and dorsal cutaneous branch blocks are used for small finger injuries. Most ring finger injuries require complete

wrist block.

156 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

HISTORY • Forearm 5

Fracture/dislocation

Distal radius and scaphoid
fractures commonly result
from fall on outstretched
hand

Repetitive Use of
motion power tools

Flexed wrist position Pressure aginst
hard surface

Abnormal work
postures may lead
to compression
neuropathies

QUESTION ANSWER CLINICAL APPLICATION
1. Age
Young Trauma: fractures and dislocations, ganglions
2. Pain Middle aged, elderly Arthritis, nerve entrapments, overuse
a. Onset
b. Location Acute Trauma
Chronic Arthritis
3. Stiffness Dorsal Kienböck’s disease, ganglion
Volar Carpal tunnel syndrome (CTS), ganglion (esp. radiovolar)
4. Swelling Radial Scaphoid fracture, de Quervain’s tenosynovitis, arthritis
Ulnar Triangular fibrocartilage complex (TFCC) tear, tendinitis
5. Instability (e.g., ECU)
6. Mass With dorsal pain
7. Trauma With volar pain (at night) Kienböck’s disease
8. Activity Carpal tunnel syndrome
9. Neurologic Joint: after trauma
Joint: no trauma Fracture or sprain
symptoms Along tendons Arthritides, infection, gout
Flexor or extensor tendinitis (calcific), de Quervain’s disease
10. History of Popping, snapping
arthritides Carpal instability (e.g., scapholunate dislocation)
Along wrist joint
Ganglion
Fall on hand
Fractures: distal radius, scaphoid; dislocation: lunate; TFCC tear
Repetitive motion (e.g., typing)
CTS, de Quervain’s tenosynovitis
Numbness, tingling
Nerve entrapment (e.g., CTS), thoracic outlet syndrome,
Weakness radiculopathy (cervical spine)
Nerve entrapment (median, ulnar, radial)
Multiple joints involved
Arthritides

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 157

5 Forearm • PHYSICAL EXAM

Distal Radius Fracture Scaphoid Fracture Carpal Dislocation

Clinical
findings.
Pain,
tenderness,
and swelling
in anatomic
snuffbox

Clinical appearance of Typical deformity. Anterior
deformity due to severely bulge of dislocated lunate
displaced fracture of
distal radius

de Quervain’s with Ganglion Cyst
Disease
C.A. Luce Firm, rubbery, sometimes lobulated swelling
Point of exquisite over carpus, most prominent on flexion of
tenderness over Carpal Tunnel Syndrome wrist. Broken line indicates
styloid process of line of skin incision
radius and sheath Thenar
of involved tendons atrophy

EXAMINATION TECHNIQUE CLINICAL APPLICATION
Gross deformity INSPECTION
Swelling Fractures, dislocations: forearm and wrist
Wasting Bones and soft tissues Ganglion cyst
Skin changes Especially dorsal or radial Trauma (fracture/dislocation), infection
Radial and ulnar styloids Diffuse Peripheral nerve compression (e.g., CTS)
Carpal bones Loss of muscle
Infection, gout
Soft tissues PALPATION Neurovascular compromise
Warm, red Tenderness may indicate fracture
Cool, dry Snuffbox tenderness: scaphoid fracture; lunate
Palpate each separately tenderness: Kienböck’s disease
Both proximal and distal row Scapholunate dissociation
Tenderness: pisotriquetral arthritis or FCU
Proximal row tendinitis
Pisiform Tenderness over 1st compartment: de Quervain’s
disease
6 dorsal extensor compartments Tenderness indicates TFCC injury
Firm/tense compartments ϭ compartment synd.
TFCC: distal to ulnar styloid
Compartments

158 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

PHYSICAL EXAM • Forearm 5

90˚ 75˚ Wrist range of motion deviation Radial 0˚ Ulnar
Extension rotation deviation
20˚
30˚

0˚

Flexion

90˚ 80˚ 90˚ 90˚

EXAMINATION TECHNIQUE CLINICAL APPLICATION

Flex and extend RANGE OF MOTION

Radial/ulnar deviation Flex (toward palm), extend Normal: flexion 80°, extension 75°
Pronate and supinate opposite

Lateral cutaneous nerve In same plane as the palm Normal: radial 15-25°, ulnar 30-45°
of forearm (C6)
Medial cutaneous nerve Flex elbow 90°, rotate Normal: supinate 90°, pronate 80-90° (only 10-15° in
of forearm (T1) wrist wrist; most motion is in elbow)
Posterior cutaneous nerve
of forearm NEUROVASCULAR

Radial nerve (C6-7) Sensory
PIN (C6-7)
Ulnar nerve (C8) Lateral forearm Deficit indicates corresponding nerve/root lesion
Median nerve (C7)
Median nerve (C6) Medial forearm Deficit indicates corresponding nerve/root lesion
Musculocutaneous (C6)
Posterior forearm Deficit indicates corresponding nerve/root lesion
C6
Motor

Resisted wrist extension Weakness ϭ ECRL/B or corresponding nerve/root lesion
Resisted ulnar deviation Weakness ϭ ECU or corresponding nerve/root lesion
Resisted wrist flexion Weakness ϭ FCU or corresponding nerve/root lesion
Resisted wrist flexion Weakness ϭ FCR or corresponding nerve/root lesion
Resisted pronation Weakness ϭ pronator teres or corresponding nerve/
root lesion
Resisted supination
Weakness ϭ biceps or corresponding nerve/root lesion

Reflex

Brachioradialis Hypoactive/absence indicates corresponding
radiculopathy

Pulses

Radial, ulnar Diminished/absent ϭ vascular injury or compromise
(perform Allen test)

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 159

5 Forearm • PHYSICAL EXAM

Phalen’s test (wrist flexion) Tinel’s sign Carpal compression test

Provocative tests elicit paresthesias in hand.

Scaphoid shift test

Radial deviation The Finkelstein test exacerbates the pain; it
is performed by flexing the thumb and then
placing the wrist in ulnar deviation.

The thumb Ulnar deviation
applies dorsal
pressure on the
scaphoid
tubercle

EXAMINATION TECHNIQUE CLINICAL APPLICATION / DDX

Durkan carpal SPECIAL TESTS
compression
Phalen test Manual pressure on median nerve at Reproduction of symptoms (e.g., tingling, numbness):
Tinel carpal tunnel median nerve compression (most sensitive test for
Finkelstein carpal tunnel syndrome [CTS])
“Piano key”
Watson (scaphoid Flex both wrists for 1minute Reproduction of symptoms (e.g., tingling): median n.
shift) compression (CTS)
Allen test
Tap volar wrist (CT/TCL) Reproduction of symptoms (e.g., tingling): median n.
compression (CTS)

Flex thumb into palm, ulnarly deviate Pain in 1st dorsal compartment (APL/EPB tendons)

the wrist suggests de Quervain’s tenosynovitis

Stabilize ulnar and translate radius Laxity or subluxation (click) indicates instability of DRUJ
dorsal and volar

Push dorsally on distal pole of scaph- A click or clunk (scaphoid subluxating dorsally over rim

oid, bring wrist from ulnar to radial of distal radius) is positive for carpal instability

deviation (scapholunate dissociation)

Occlude both radial and ulnar arteries Delay or absence of “pinking up” of the palm and fin-

manually, pump fist, then release gers suggests arterial compromise of the artery

one artery only released

160 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: ORIGINS AND INSERTIONS • Forearm 5

Anterior (volar)

Brachioradialis muscle Brachialis muscle

Extensor carpi radialis longus muscle Pronator teres muscle (humeral head)

Extensor carpi radialis brevis, Common Common Pronator teres, flexor
extensor digitorum, extensor extensor flexor carpi radialis, palmaris
digiti minimi, extensor carpi tendon tendon longus, flexor carpi ulnaris,
ulnaris muscles flexor digitorum superficialis
(humeroulnar head) muscles

Brachialis muscle

Biceps brachii muscle Flexor digitorum superficialis muscle
(humeroulnar head)

Pronator teres muscle (ulnar head)

Supinator muscle Flexor digitorum profundus muscle

Flexor digitorum superficialis
muscle (radial head)

Pronator teres muscle

Flexor pollicis longus muscle

Ulna

Radius Pronator quadratus muscle
Pronator quadratus muscle
Note: Attachments of intrinsic
Brachioradialis muscle muscles of hand not shown
Abductor pollicis longus muscle
Flexor carpi ulnaris muscle
Flexor carpi radialis muscle Extensor carpi ulnaris muscle

Flexor pollicis Flexor digitorum superficialis muscle
longus muscle

Flexor digitorum profundus muscle

Origins Insertions

PROXIMAL ULNA PROXIMAL RADIUS

ANTERIOR

Origins

Flexor digitorum superficialis (1 head) Flexor digitorum superficialis (1 head)
Pronator teres
Supinator
Flexor digitorum profundus

Insertions

Brachialis Biceps
Supinator

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 161

5 Forearm • MUSCLES: ORIGINS AND INSERTIONS

Posterior (dorsal)

Note: Attachments of intrinsic Triceps brachii muscle (medial head)
muscles of hand not shown

Triceps brachii tendon

Flexor carpi ulnaris muscle (humeral Anconeus muscle
origin via common flexor tendon) Biceps brachii muscle
Supinator muscle
Flexor carpi ulnaris muscle (ulnar origin)
Flexor digitorum profundus muscle Abductor pollicis longus muscle
Pronator teres muscle
Extensor carpi ulnaris muscle (ulnar origin) Extensor pollicis brevis muscle
Extensor pollicis longus muscle
Extensor indicis muscle Radius
Ulna

Extensor carpi radialis longus muscle Brachioradialis muscle
Extensor carpi radialis brevis muscle Abductor pollicis longus muscle

Extensor carpi ulnaris muscle Extensor pollicis brevis muscle
Extensor digitorum muscle (central bands) Extensor pollicis longus muscle
Extensor indicis muscle
Extensor digiti minimi muscle

Extensor digitorum muscle (lateral bands)

Origins Insertions

PROXIMAL ULNA PROXIMAL RADIUS
POSTERIOR
Flexor carpi ulnaris
Flexor digitorum profundus Origins
Supinator none

Triceps Insertions
Anconeus Biceps
Supinator

162 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: ANTERIOR COMPARTMENT • Forearm 5

Biceps brachii muscle Medial cutaneous nerve of forearm
Ulnar nerve
Brachial artery and median nerve Triceps brachii muscle
Medial intermuscular septum
Lateral cutaneous nerve of forearm Ulnar artery
(terminal musculocutaneous nerve)
Medial epicondyle of humerus
Brachialis muscle
Common flexor tendon
Biceps brachii tendon
Pronator teres muscle
Radial artery
Flexor carpi Superficial
Bicipital aponeurosis radialis muscle flexor
(lacertus fibrosus) [FCR] muscles
Brachioradialis muscle
Palmaris longus
Extensor carpi radialis muscle [PL]
longus muscle [ECRL]
Flexor carpi
Extensor carpi radialis ulnaris muscle
brevis muscle [ECRB] [FCU]

Flexor pollicis longus Flexor digitorum
muscle and tendon superficialis muscle
[FPL] [FDS]

Radial artery Palmaris longus tendon
Dorsal cutaneous branch of ulnar nerve
Median nerve
Ulnar artery and nerve
Palmar carpal ligament Flexor digitorum superficialis tendons
(continuous with Pisiform
extensor retinaculum) Palmar cutaneous branch of median nerve

Thenar muscles Hypothenar muscles

Palmar aponeurosis

MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT

Pronator teres (PT) Medial epicondyle SUPERFICIAL FLEXORS Pronate and Can compress me-
Humeral head Proximal ulna flex forearm dian nerve (prona-
Ulnar (deep) head Medial epicondyle Lateral radius Median tor syndrome)
middle 1⁄3 Flex wrist, ra-
Flexor carpi Medial epicondyle dial deviation Radial artery is im-
radialis (FCR) Base of 2nd (and Median mediately lateral
Palmaris longus 1. Medial 3rd) metacarpal Median Flex wrist
(PL) epicondyle Used for tendon
Flexor retinaculum/ Flex wrist, ulnar transfers, 10%
Flexor carpi ulnaris 2. Posterior ulna palmar aponeurosis deviation congenitally absent
(FCU)
Pisiform, hook of Ulnar Most powerful wrist
hamate, 5th MC flexor. May com-
press ulnar nerve

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 163

5 Forearm • MUSCLES: ANTERIOR COMPARTMENT

Biceps brachii muscle Ulnar nerve

Brachialis muscle Median nerve

Lateral cutaneous nerve of forearm (cut) Brachial artery
(from musculocutaneous nerve)
Medial intermuscular septum
(Common) radial nerve
Deep branch Pronator teres muscle (humeral head)
(cut and reflected)
Superficial branch Medial epicondyle

Biceps brachii tendon Flexor carpi radialis and palmaris
longus tendons (cut)
Radial recurrent artery Anterior ulnar recurrent artery
(Leash of Henry)
Flexor digitorum superficialis
Radial artery muscle (humeroulnar head)
Ulnar artery
Supinator muscle
Common interosseous artery
Brachioradialis muscle
Pronator teres muscle (ulnar head) (cut)
Pronator teres muscle (cut)
Flexor digitorum superficialis Anterior interosseous artery
muscle (radial head) [FDS]
Flexor carpi ulnaris muscle
Flexor pollicis longus muscle
Flexor digitorum superficialis [FDS] muscle
Palmar carpal ligament
(continuous with extensor Ulnar artery
retinaculum) with palmaris
longus tendon (cut and reflected) Ulnar nerve and dorsal cutaneous branch

Flexor carpi radialis Median nerve
tendon (cut) Palmar cutaneous branches of median and
ulnar nerves (cut)
Superficial palmar branch Pisiform
of radial artery Deep palmar branch of ulnar artery
and deep branch of ulnar nerve
Superficial branch of ulnar nerve

Transverse carpal ligament
(flexor retinaculum)

MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT

SUPERFICIAL FLEXORS Sublimus test
will isolate and
Flexor digito- 1. Medial epicondyle Middle phalan- Median Flex PIPJ (also test function
rum superfici- proximal ulna ges of digits flex digit and
alis (FDS) (not thumb) wrist)
2. Anteroproximal
radius

FDS is often considered a “middle flexor” because of its position between muscles.

164 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: ANTERIOR COMPARTMENT • Forearm 5

Brachialis muscle Ulnar nerve
Musculocutaneous nerve Median nerve

(becomes) Brachial artery
Lateral cutaneous nerve of forearm
Medial intermuscular septum
Lateral intermuscular septum
Pronator teres muscle
Radial nerve (cut and reflected)

Lateral epicondyle Anterior ulnar recurrent artery

Biceps brachii tendon (cut) Medial epicondyle of humerus

Radial recurrent artery Flexor carpi radialis,
palmaris longus,
Radial artery flexor digitorum superficialis
(humeroulnar head), and
Supinator muscle flexor carpi ulnaris
muscles (cut)
Posterior and anterior
interosseous arteries

Flexor digitorum superficialis Posterior ulnar recurrent artery
muscle (radial head) (cut) Ulnar artery
Common interosseous artery
Pronator teres muscle
(cut and reflected)

Radial artery Pronator teres muscle (ulnar head) (cut)
Median nerve (cut)
Flexor pollicis longus [FPL] Flexor digitorum profundus muscle [FDP]
muscle and tendon (cut)

Radius

Pronator quadratus muscle [PQ] Anterior interosseous artery and nerve

Brachioradialis tendon (cut) Ulnar nerve and dorsal cutaneous branch

Radial artery and Palmar carpal branches of radial and ulnar arteries
superficial palmar branch
Flexor carpi ulnaris tendon (cut) [FCU]
Flexor pollicis longus
tendon (cut) [FPL] Pisiform

Flexor carpi radialis Deep palmar branch of ulnar artery
tendon (cut) [FCR] and deep branch of ulnar nerve
Hook of hamate
Abductor pollicis longus
tendon [APL] 5th metacarpal bone

Extensor pollicis brevis
tendon [EPB]

1st metacarpal bone

MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT

DEEP FLEXORS Flex DIPJ Avulsion: Jersey finger
(also flex
Flexor digitorum Anterior ulna & Distal phalanx Median/AIN digit and Profundus test will iso-
profundus (FDP) interosseous (IF, ϩ/Ϫ MF) Ulnar wrist) late and test function
membrane Distal phalanx Flex thumb IP FDP and FPL are most
(RF, SF, ϩ/Ϫ MF) susceptible to Volk-
Pronate mann’s contracture
Flexor pollicis Anterior radius Distal phalanx Median/AIN forearm Primary pronator
longus (FPL) & proximal of thumb (initiates pronation)
ulna

Pronator quadra- Medial distal Anterior distal Median/AIN
radius
tus (PQ) ulna

• AIN innervates all three deep flexors. It is tested by making “OK” signs.

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 165

5 Forearm • MUSCLES: POSTERIOR COMPARTMENT

Superior ulnar collateral artery Triceps brachii muscle
(anastomoses distally with Brachioradialis muscle
posterior ulnar recurrent artery) Extensor carpi radialis longus (ECRL) muscle
Common extensor tendon
Ulnar nerve Extensor carpi radialis brevis (ECRB) muscle
Extensor digitorum (EDC) muscle
Medial epicondyle of humerus

Olecranon of ulna

Anconeus muscle

Flexor carpi ulnaris muscle

Extensor carpi ulnaris (ECU) muscle Extensor digiti minimi (EDM) muscle

Abductor pollicis longus muscle

Extensor retinaculum Extensor pollicis brevis muscle
(compartments numbered)
Extensor pollicis longus tendon
Dorsal cutaneous branch of ulnar nerve Extensor carpi radialis brevis tendon
Extensor carpi radialis longus tendon
Extensor carpi ulnaris tendon
Extensor digiti minimi tendon 6 5 4 321 Superficial branch of radial nerve

Extensor digitorum tendons Abductor pollicis longus tendon
Extensor indicis tendon Extensor pollicis brevis tendon
Extensor pollicis longus tendon
5th metacarpal bone
Anatomical snuffbox

MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT

SUPERFICIAL EXTENSORS Forearm Muscular plane in
extension Kocher approach
Anconeus Posterior-lateral Posterior-proximal Radial Digit extension Tendon avulsion:
epicondyle ulna P2: boutonniere
Extensor digito- SF extension P3: mallet finger
rum commu- Lateral MCP: Sag. band Radial-PIN Aka EDQ: In 5th
nis (EDC) epicondyle P2: Central slip Hand extension dorsal compartment
P3: Term. insert and adduction Can cause painful
Extensor digiti Lateral snapping over ulna
minimi (EDM) epicondyle Same as above in Radial-PIN Forearm flexion
small finger Wrist extension Is a deforming force
Extensor carpi Lateral in radius fractures
ulnaris (ECU) epicondyle Base of 5th MC Radial-PIN Aka ECRL

Mobile Wad ECRB degenerates in
tennis elbow
Brachioradialis Lateral condyle Lateral distal Radial
(BR) radius Radial
Extensor carpi Lateral condyle Base of 2nd MC
radialis longus
Extensor carpi Lateral Base of 3rd MC Radial-PIN Wrist extension
radialis brevis epicondyle

166 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: POSTERIOR COMPARTMENT • Forearm 5

Branches of Superior ulnar collateral Middle collateral branch of
brachial artery Inferior ulnar collateral deep artery of arm
(posterior branch)
Lateral intermuscular septum
Medial intermuscular septum
Brachioradialis muscle
Ulnar nerve
Extensor carpi radialis longus muscle
Posterior ulnar recurrent artery

Medial epicondyle of humerus Lateral epicondyle of humerus

Triceps brachii tendon (cut) Common extensor tendon (partially cut)

Olecranon of ulna Extensor carpi radialis brevis muscle
Anconeus muscle Supinator muscle

Flexor carpi ulnaris muscle Deep branch of radial nerve

Recurrent interosseous artery Pronator teres muscle (slip of insertion)
Posterior interosseous artery Radius
Posterior interosseous nerve
Ulna
Extensor pollicis longus (EPL) muscle Abductor pollicis longus (APL) muscle

Extensor indicis (EIP) muscle Extensor pollicis brevis (EPB) muscle

Anterior interosseous artery (termination) 6 5 4 321 Extensor carpi radialis brevis tendon
Extensor carpi radialis longus tendon
Extensor carpi ulnaris tendon (cut)
Extensor digiti minimi tendon (cut) Radial artery

Extensor digitorum 1st metacarpal bone
communis tendons (cut)
2nd metacarpal bone
Extensor retinaculum
(compartments numbered) 1st dorsal
interosseous muscle
5th metacarpal bone

MUSCLE ORIGIN INSERTION NERVE ACTION COMMENT

Supinator Posterior medial DEEP EXTENSORS
ulna
Abductor pollicis Proximal lateral Radial-PIN Forearm supina- PIN pierces muscles,
longus (APL) Posterior radius/ radius tion can be compressed
ulna
Extensor pollicis Base of 1st Radial-PIN Abduct and ex- de Quervain’s dis-
brevis (EPB) Posterior radius thumb meta- tend thumb ease (may have
Extensor pollicis carpal (CMCJ) multiple slips)
longus (EPL) Posterior ulna
Extensor indicis Base of thumb Radial-PIN Extend thumb Radial border of
proprius (EIP) Posterior ulna prox. phalanx (MCPJ) snuffbox

Base of thumb Radial-PIN Extend thumb Tendon turns 45° on
distal phalanx (IPJ) Lister’s tubercle

Same as EDC Radial-PIN Index finger Ulnar to EDC tendon;
& EDM extension last PIN muscle

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 167

5 Forearm • MUSCLES: CROSS SECTIONS

Median antebrachial vein Flexor digitorum superficialis muscle
(radial head)
Pronator teres muscle Anterior branch of medial cutaneous
Radial artery and superficial branch of radial nerve nerve of forearm

Radius Flexor pollicis longus muscle
Interosseous membrane
Brachioradialis muscle Flexor carpi radialis muscle
Ulnar artery and median nerve
Lateral cutaneous nerve of forearm Palmaris longus muscle
(from musculocutaneous nerve) Flexor digitorum superficialis
muscle (humeroulnar head)
Supinator muscle Radius Common interosseous artery
Ulnar nerve
Deep branch of radial nerve (PIN) Flexor carpi ulnaris muscle

Extensor carpi radialis longus muscle Basilic vein
Flexor digitorum profundus muscle
Extensor carpi radialis brevis muscle
Extensor digitorum muscle Ulna and antebrachial fascia
Anconeus muscle
Extensor digiti minimi muscle Posterior cutaneous nerve of
forearm (from radial nerve)
Extensor carpi ulnaris muscle Palmaris longus muscle
Flexor carpi radialis muscle Flexor digitorum superficialis muscle
Median nerve
Brachioradialis muscle Ulnar artery and nerve
Radial artery and superficial Flexor carpi ulnaris muscle
branch of radial nerve Anterior interosseous artery and nerve (AIN)
Flexor pollicis longus muscle (from median nerve)
Extensor carpi radialis longus Flexor digitorum profundus muscle
muscle and tendon Ulna and antebrachial fascia

Radius Interosseous membrane and extensor
Extensor carpi radialis brevis pollicis longus muscle
muscle and tendon Posterior interosseous artery and nerve (PIN)
Abductor pollicis longus muscle (continuation of deep branch of radial nerve)
Extensor digitorum muscle Palmaris longus tendon
Extensor digiti minimi muscle Median nerve
Flexor digitorum superficialis muscle and tendons
Extensor carpi ulnaris muscle Flexor carpi ulnaris muscle and tendon
Flexor carpi radialis tendon
Radial artery Ulnar artery and nerve
Brachioradialis tendon Dorsal cutaneous branch of ulnar nerve
Abductor pollicis
longus tendon Flexor digitorum profundus muscle and tendons
Superficial branch Antebrachial fascia
of radial nerve Ulna
Extensor pollicis Extensor carpi ulnaris tendon
brevis tendon Pronator quadratus muscle and interosseous membrane
Extensor carpi radialis Extensor indicis muscle and tendon
longus tendon
Extensor digiti minimi tendon
Extensor carpi radialis brevis tendon
Extensor digitorum tendons (common tendon to digits 4 and 5 at this level)
Flexor pollicis longus muscle
Extensor pollicis longus tendon

STRUCTURE RELATIONSHIP
RELATIONSHIPS
Ulnar nerve/artery Run under FDS on top of FDP muscles, ulnar to the artery
Superior radial nerve Runs under the brachioradialis muscle/tendon, radial to the artery
Radial artery Is radial (lateral) to FCR muscle and tendon
Median nerve Is radial (lateral) to ulnar nerve, runs between FDP and FPL muscles into the carpal tunnel
Post. interosseous Pierces supinator muscle proximally, runs between APL & EPL along interosseous membrane

nerve (PIN)

168 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

MUSCLES: COMPARTMENTS • Forearm 5

Incisions for Compartment Syndrome of Forearm and Hand

Wick catheter in volar compartment Volar incision

Antebrachial (encircling) fascia

Radial a. and superficial Median n.
branch of radial n. Ulnar a. and n.

Antebrachial (encircling) fascia

Radius Anterior interosseous a. and n.

Dorsal interosseous a. and n. Interosseous membrane
Deep branch of radial n.
Wick catheter in dorsal compartment Ulna
Dorsal incision
Section through midforearm

Volar Dorsal
forearm incision forearm incision

Note: fascial in- Hand incisions (for
cisions are the decompression of
same lines as interosseous muscles)
skin incisions

STRUCTURE CONTENTS

Superficial COMPARTMENTS
Middle
Deep Anterior
Pronator teres (PT), flexor carpi radialis (FCR), palmaris longus (PL), flexor carpi ulnaris (FCU)
Superficial Flexor digitorum superficialis (FDS)
Deep Flexor digitorum profundus (FDP), flexor pollicis longus (FPL), pronator quadratus (PQ)

Palmar incision Posterior
Dorsal incision Anconeus, ext. digit. communis (EDC), ext. digit. minimi (EDM), ext. carpi ulnaris (ECU)
Supinator, abd. poll. longus (APL), ext. poll. brevis (EPB), ext. poll. longus (EPL), ext. indicis proprius (EIP)

Mobile Wad
Brachioradialis, extensor carpi radialis longus (ECRL), extensor carpi radialis brevis (ECRB)

FASCIOTOMIES
Releases the entire anterior compartment
Releases the entire posterior compartment and mobile wad

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 169

5 Forearm • NERVES

Anterior view
Musculocutaneous nerve

Median nerve (C[5], 6, 7, 8, T1) Medial Cords of
Inconstant contribution Posterior brachial
Lateral plexus
Pronator teres muscle (humeral head)
Articular branch Medial brachial
cutaneous nerve
Flexor carpi radialis muscle
Palmaris longus muscle Medial antebrachial
cutaneous nerve
Pronator teres muscle (ulnar head)
Flexor digitorum superficialis muscle Axillary nerve
(turned up) Radial nerve

Ulnar nerve

Flexor digitorum profundus muscle
(lateral part supplied by median
[anterior interosseous] nerve; medial
part supplied by ulnar nerve)

Anterior interosseous nerve

Flexor pollicis longus muscle BRACHIAL PLEXUS

Pronator quadratus muscle Medial and Lateral Cords

Palmar cutaneous branch Median Nerve (C[5]6-T1): In anterior forearm,
of median nerve under lacertus fibrosus* (biceps aponeurosis),
between the 2 heads of pronator teres.* The
AIN (anterior interosseous nerve) branches,
then nerve passes under arch of FDS*, then
on/between FDP and FPL into carpal tunnel*.
Palmar cutaneous branch divides 5cm proxi-
mal to wrist & runs b/w the FCR and PL. The
motor recurrent branch divides after (50%),
under (30%), or through (20%) the transverse
carpal ligament (TCL).

Sensory: None (in forearm, see Hand)
Motor: • Anterior compartment

‫ ؠ‬Pronator teres (PT)
‫ ؠ‬Flexor carpi radialis (FCR)
‫ ؠ‬Palmaris longus (PL)
‫ ؠ‬Flexor dig. super. (FDS)

Anterior Interosseous Nerve (AIN): Branches proximally, then runs along the interosseous
membrane with anterior interosseous artery, between FPL & FDP

Sensory: Volar wrist capsule
Motor: • Anterior compartment—deep flexors

‫ ؠ‬Flexor digitorum profundus (FDP) to 2nd (3rd) digits
‫ ؠ‬Flexor pollicis longus (FPL)
‫ ؠ‬Pronator quadratus (PQ)

*Potential site of nerve compression.

170 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

NERVES • Forearm 5

Radial nerve (C5, 6, 7, 8, [T1]) Inconstant contribution

Superficial (terminal) branch

Deep (terminal) branch (PIN) Posterior view
Lateral epicondyle

Anconeus muscle

Brachioradialis muscle

Extensor carpi radialis longus muscle

Supinator muscle

Extensor carpi radialis brevis muscle Posterior cutaneous
Extensor carpi ulnaris muscle nerve of forearm

Extensor digitorum muscle and
extensor digiti minimi muscle

Extensor indicis muscle

Extensor pollicis longus muscle

Abductor pollicis longus muscle

Extensor pollicis brevis muscle Superficial branch of
radial nerve and dorsal
Posterior interosseous nerve digital branches
(continuation of deep branch of
radial nerve distal to supinator muscle)

Superficial (sensory) branch of radial nerve

Cutaneous innervation from
radial and axillary nerves

BRACHIAL PLEXUS

Posterior Cord

Radial (C5-T1): Enters forearm b/w brachioradialis (BR) & brachialis, then divides
into deep and superficial branches. Superficial br. runs under BR to thumb web
space. It can be compressed under the BR tendon.* It is lateral to the radial ar-
tery. Deep br. pierces the supinator, then becomes the PIN.

Sensory: Posterior forearm: via posterior cutaneous nerve of forearm
Motor: Anconeus

• Mobile wad
‫ ؠ‬Brachioradialis (BR)
‫ ؠ‬Extensor carpi radialis longus (ECRL)

Posterior Interrosseous Nerve (PIN): Runs past vascular Leash of Henry* (recurrent radial artery) and ECRB, through the
arcade of Frohse* (proximal supinator), into the supinator, past its distal edge,* then along interosseous membrane under
EDC and between APL and EPL.

Sensory: Dorsal wrist capsule (in 4th dorsal compartment)
Motor: • Mobile wad

‫ ؠ‬Extensor carpi radialis brevis (ECRB)
• Posterior compartment—superficial extensors

‫ ؠ‬Supinator
‫ ؠ‬Extensor digitorum communis (EDC)
‫ ؠ‬Extensor digiti minimi (EDM or EDQ)
‫ ؠ‬Extensor carpi ulnaris (ECU)
• Posterior compartment—deep extensors
‫ ؠ‬Abductor pollicis longus (APL)
‫ ؠ‬Extensor pollicis brevis (EPB)
‫ ؠ‬Extensor pollicis longus (EPL)
‫ ؠ‬Extensor indicis proprius (EIP)

*Potential site of nerve compression.

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 171

5 Forearm • NERVES

Anterior view Posterior view Ulnar nerve
([C7], 8, T1)(no
Radial nerve branches above elbow)
Posterior cutaneous
nerve of forearm Inconstant contribution
(C[5], 6, 7, 8)

Medial Articular branch Medial epicondyle
cutaneous (behind condyle)
nerve of Flexor digitorum
forearm profundus muscle
(C8, T1) (medial part only;
lateral part supplied
Lateral cutaneous nerve of by anterior inter-
forearm (C5, 6, [7]) (terminal part osseous branch of
of musculocutaneous nerve) median nerve)

Cutaneous Flexor carpi ulnaris
innervation muscle (drawn aside)
(via lateral
cutaneous Dorsal cutaneous branch
nerve of of ulnar nerve
forearm)
Palmar cutaneous branch

Superficial (sensory) branch

Deep (motor) branch

Anterior (palmar) view Posterior (dorsal) view

BRACHIAL PLEXUS

Lateral Cord

Musculocutaneous (C5-7): Exits between biceps & brachialis, purely sensory, runs in subcutaneous tissues above the
brachioradialis
Sensory: Radial forearm: via lateral cutaneous nerve of forearm
Motor: None (in forearm)

MEDIAL CORD

Medial Cutaneous Nerve of Forearm (Antebrachial Cutaneous) (C8-T1): Branches directly from the cord, runs subcu-
taneously anterior to medial epicondyle into the medial forearm
Sensory: Medial forearm
Motor: None

Ulnar (C[7]8-T1): Runs posterior to medial epicondyle in cubital tunnel,* then through FCU heads/aponeurosis,* then
runs on FDP (under FDS) to wrist. The dorsal and palmar cutaneous branches divide 4-5cm proximal to wrist, then
the nerve runs into the ulnar tunnel (Guyon’s canal*), where it divides into deep/motor & superficial/sensory branches
Sensory: None (in forearm)
Motor: • Anterior compartment

‫ ؠ‬Flexor carpi ulnaris (FCU)
‫ ؠ‬Flexor digitorum profundus (FDP) to (3rd), 4th, 5th digits

*Potential site of nerve compression.

172 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

ARTERIES • Forearm 5

Brachial artery Radial artery and Ulnar artery and

Bicipital aponeurosis palmar carpal branch palmar carpal
Supinator muscle branch
Superficial palmar
branch of radial artery Palmar carpal

Brachioradialis Superficial palmar arterial arch
muscle
Radial artery branch of ulnar artery Pisiform

Pronator teres Deep palmar Median nerve
muscle (partially
cut) Humeral (arterial) arch Guyon’s canal

Flexor pollicis head Pronator Abductor digiti
(cut) teres minimi muscle
(cut)
Ulnar muscle Anterior (palmar) view
Deep palmar branch of ulnar
head artery and deep branch of

Flexor digitorum

profundus muscle

longus muscle Flexor carpi ulnar nerve

Flexor carpi ulnaris muscle Ulna Radius
radialis Ulnar artery

tendon (cut) and nerve Abductor Radial artery
digiti
Deep palmar minimi Dorsal
branch of ulnar scaphoid branch

artery and deep with muscle Abductor pollicis
branch of Posterior (dorsal) view brevis muscle
ulnar nerve C.A. Luce

COURSE BRANCHES

FOREARM

Radial Artery

Runs over the pronator teres, on Radial recurrent (leash of Henry)
FDS & FPL lateral to the FCR Muscular branches

Ulnar Artery

Runs under the ulnar head of the Anterior ulnar recurrent
pronator teres, on the FDP mus-
cle, lateral and adjacent to the Posterior ulnar recurrent
ulnar nerve
Common interosseous
‫ ؠ‬Anterior interosseous
‫ ؠ‬Posterior interosseous
‫ ؠ‬Recurrent interosseous

Muscular branches

WRIST

Radial Artery

Lateral to FCR tendon, wraps dor- Palmar carpal branch Deep to flexor tendons
sally, under the APL & EPB ten- Dorsal carpal branch Deep to extensor tendons
dons, between the 2 heads of 1st Superficial palmar branch Anastomoses w/super. palmar arch
dorsal interosseous muscles, to Supplies 25% of scaphoid (distal)
the palm ending in deep arch ‫ ؠ‬Palmar scaphoid branch Supplies 75% of scaphoid (proximal)
Dorsal scaphoid branch Terminal branch of radial artery in hand
Deep palmar arch

Ulnar Artery

On transverse carpal ligament (TCL) Palmar carpal branch Deep to flexor tendons
into Guyon’s canal, divides into Dorsal carpal branch Deep to extensor tendons
deep and superficial palmar Deep palmar branch Anastomoses with deep palmar arch
branches Superficial palmar arch Terminal branch of the ulnar artery

• Allen test: Occlude both radial and ulnar arteries at the wrist. Patient squeezes fist to exsanguinate the hand. Release
one artery and check for hand perfusion. Repeat with the other artery. Test confirms patency of arches/vessels.

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 173

5 Forearm • DISORDERS Superficial branch
of radial nerve
Ulnar
styloid

TFCC tear

Lunate fossa Extensor pollicis longus, Extensor
extensor pollicis brevis, retinaculum
abductor pollicis longus tendons
Triangular
fibrocartilage (disc) Course of abductor pollicis longus and extensor pollicis brevis
tendons through 1st compartment of extensor retinaculum

Ganglion of Wrist Extensor tendon
retracted

Carpal ligament
and capsules

Excision of ganglion via
transverse incision

TFCC tear

Triangular fibrocartilage tear (TFCC)

DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT

TRIANGULAR FIBROCARTILAGE COMPLEX (TFCC) TEAR 1. Class 1: repair or de-
bride tear (fix styloid
• Can be traumatic (class 1) or Hx: Ulnar wrist pain, ϩ/Ϫ XR: Usually normal; tears fracture if needed)
degenerative (class 2) popping/grinding assoc. w/styloid base fx
PE: TFC is TTP, ϩ TFCC, MRA: Study of choice for 2. Class 2: NSAIDs,
• Only periphery is vascular grind, ϩ/Ϫ piano key diagnosis of tears splint; ulnar shortening
(i.e., peripheral tear can be procedure
repaired)
1. Splint and NSAIDs
de QUERVAIN’S TENOSYNOVITIS 2. Corticosteroid injection

• Inflammation of first dorsal Hx: Radial pain/swelling XR: Usually normal into sheath
compartment (APL/EPB PE: Tenderness at 1st MR: No indication 3. Surgical release
tendons) dorsal compartment,
ϩ Finkelstein’s test 1. Observation if asymp-
• Middle age women #1. tomatic
• Assoc. w/tendon abnormality GANGLION CYST
2. Aspiration (recurrence
• Synovial fluid–filled cyst aris- Hx: Mass, ϩ/Ϫ pain XR: Wrist series usually 20%)
ing from a wrist joint PE: Palpable, mobile normal
mass, ϩ/Ϫ tenderness, MR: Will show cyst well, 3. Excision (including
• Most common mass in wrist needed only if diagnosis stalk of cyst; recur-
• Dorsal wrist most common ϩ transillumination is uncertain rence Ͻ10%)

site (usually from SL joint)

174 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

DISORDERS • Forearm 5

Median nerve Pronator syndrome Compression by flexor
digitorum superficialis
Supracondylar Flexion of middle muscle
process finger against
resistance Compression by
Ligament of Anterior pronator teres muscle
Struthers interosseous n.

Medial Carpal Pronation
epicondyle tunnel against resistance

Lacertus Compression
fibrosus by lacertus
fibrosus
Pronator teres m.
Humeral head
Ulnar head
Flexor digitorum
superficialis m. and arch

Flexor pollicis longus m.

Anterior interosseous syndrome Flexion of wrist
against resistance
Normal Abnormal

Carpal tunnel syndrome Median
nerve
Incision Transverse
site carpal ligament

Hand posture in anterior interosseous syn-
drome due to paresis of flexor digitorum
profundus and flexor pollicis longus muscles

Decompressed
carpal tunnel

Compressed
median nerve

DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT

• Proximal median nerve MEDIAN NERVE COMPRESSION 1. Activity modification/
compression rest
Pronator Syndrome
• Sites: 1. Ligament of 2. Splinting, NSAIDs
Struthers, 2. Pronator Hx: Numbness, tingling, XR: Look for supracondylar 3. Surgical decompres-
teres, 3. Lacertus fibrosis, ϩ/Ϫ weakness process off humerus
4. FDS aponeurosis/arch PE: Decreased palm sen- EMG/NCS: Can confirm sion of all proximal
sation, ϩ pronator or FDS dx (can also be normal) compression sites
• Rare nerve compression sign
• Same sites at pronator 1. Activity modification
AIN Syndrome 2. Splinting, NSAIDs
syndrome 3. Surgical decompres-
• Motor symptoms only Hx: Weakness, ϩ/Ϫ pain XR: Usually normal
PE: Weak thumb (FPL) and EMG/NCS: Will confirm sion
• Compression in carpal IF (FDP) pinch diagnosis if unclear
tunnel 1. Activity modification
Carpal Tunnel Syndrome 2. Night splints, NSAIDs
• Most common neuropathy 3. Corticosteroid injection
• Associated with metabolic Hx: Numbness, ϩ/Ϫ pain XR: Usually normal 4. Carpal tunnel release
PE: ϩ/Ϫ thenar atrophy, EMG/NCS: Will confirm
diseases (thyroid, diabe- ϩ Durkin’s, ϩ/Ϫ Phalen’s, diagnosis if unclear (incr.
tes), pregnancy & Tinel’s tests latency, decr. velocity)

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 175

5 Forearm • DISORDERS

Radial n. Radial Nerve Compression Motor signs

Recurrent Sensory signs in radial tunnel syndrome Posterior interosseous
radial a. syndrome
Pain and Pain Paresthesia and
Posterior tenderness radiation hypesthesias Loss of wrist and
interosseous n. finger extension

Extensor
carpi radialis
brevis m.

Provocative tests for radial tunnel syndrome

Supinator
m.

Superficial
radial n.

Vascular Supination against resistance
leash of Henry

Fibrous arcade
of Frohse

Posterior interosseous n.

Innervation of Superficial

extensor mm. Tendon of radial n. at wrist

brachioradialis m.

DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT

• Compression in radial tunnel RADIAL NERVE COMPRESSION 1. Activity modification
• Sites: 1. Fibrous bands, 2. Splint, NSAIDs
PIN Syndrome 3. Surgical decompression
2. Leash of Henry, 3. ECRB,
4. Arcade of Frohse (proximal Hx: Hand & wrist XR: Look for radiocapitellar (complete release)
supinator edge), 5. Distal edge weakness, ϩ/Ϫ abnormality
of supinator elbow pain MR: Evaluate for masses 1. Activity modification
PE: Weak thumb/ EMG/NCS: Confirms diagno- 2. Splint, NSAIDs
• Compression in radial tunnel finger ext., TTP at sis & localizes lesion 3. Surgical decompression
• Same sites as above radial tunnel
• Pain only, no weakness 1. Activity modification
Radial Tunnel Syndrome 2. Wrist splint, NSAIDs
• Compression of superficial 3. Surgical decompression
radial nerve at wrist (b/w ERCL Hx: Lat. elbow pain XR: Evaluate RC joint
and BR tendons) PE: Radial tunnel MR: Evaluate for masses 1. Activity modification
TTP, no weakness EMG/NCS: Not useful 2. Splint, NSAIDs
• Sensory symptoms only 3. Surgical decompression
Wartenberg’s Syndrome
• Compression in Guyon’s canal (address underlying
• Etiology: ganglion, hamate mal- Hx: Numbness/pain XR: Usually normal cause of compression)
PE: Decr. sensation MR: Usually not helpful
union, thrombotic a., muscle IF/thumb. ϩ Tinel’s, EMG/NCS: May confirm
• Sensory (zone 3), motor (zone diagnosis
sx w/pronation
2), or mixed (zone 1) symptoms
ULNAR NERVE COMPRESSION

Ulnar Tunnel (Guyon’s Canal) Syndrome

Hx: Numbness, XR: Look for fracture
weakness in hand CT: Evaluate for fx/malunion
PE: Decr. sensation, MR: Useful for masses
ϩ/Ϫ atrophy, claw- US: Evaluate for thrombosis
ing, weakness EMG: Confirm diagnosis

176 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Volar carpal ligament Ulnar tunnel syndrome DISORDERS • Forearm 5

Palmaris Transverse carpal Ulnar nerve
brevis m. ligament Ulnar tunnel

Pisiform

Ulnar n.

Ulnar a. Zone I (motor
Zones of nerve compression and clinical signs and sensory)

Zone II Deep
(motor) (motor)
branch of
Sensory findings occur with compression in zones I and III ulnar n.

Clawing of 4th and Zone III Superficial
5th fingers (sensory) (sensory)
branch of
Interosseous ulnar n.
atrophy
Motor findings with compression in zones I and II

DESCRIPTION EVALUATION TREATMENT

CARPAL INSTABILITY Acute/early treatment:
1. Fx: ORIF of scaphoid
Carpal Instability, Dissociative (CID) 2. Ligament: SL or LT liga-

Instability within a carpal row; two main types: Hx: Trauma, pain ϩ/Ϫ popping ment repair or reconstruc-
PE: ϩ/Ϫ decreased ROM, ϩ/Ϫ tion with pin fixation
1. Dorsal intercalated segment instability (DISI) 3. Capsulodesis
‫ ؠ‬Due to scapholunate (SL) ligament disruption or snuffbox or SL/LT interval ten- Chronic/late treatment:
scaphoid fracture/nonunion 1. Limited fusion (e.g., STT
‫ ؠ‬Deformity: scaphoid flexes, lunate extends derness, ϩ Watson test (DISI) fusion for DISI)
‫ ؠ‬May lead to STT arthritis or SLAC wrist or Regan test (VISI)
1. Nonoperative: splint/cast
2. Volar intercalated segment instability (VISI) XR: Wrist & clenched fist views (esp. midcarpal)
‫ ؠ‬Due to lunotriquetral ligament disrupted (also ‫ ؠ‬DISI: SL gap Ͼ3mm, SL
requires dorsal radiocarpal lig. injury) angle Ͼ70º, “ring sign” 2. Arthrodesis (fusion)
‫ ؠ‬VISI: disrupted carpal ‫ ؠ‬Midcarpal
arches ‫ ؠ‬Radiocarpal

MRA: Can confirm ligament inj. 1. ORIF of bones with primary
repair of ligaments
Carpal Instability, Nondissociative (CIND)
2. Late: arthrodesis
• Instability between carpal rows Hx: Fall/trauma or ligament hy-
• Midcarpal or radiocarpal variations perlaxity; popping/clunking
• Associated with generalized hyperlaxity or trauma PE: Tenderness, instability
XR: Evaluate for fxs & static
to ligaments (e.g., ulnar translation at RCJ) or to carpal translation
bones (e.g., distal radius fracture) Fluoro: Dynamic carpal transl.

Carpal Instability, Combined (CIC)

• Instability both within a row & between rows Hx: Fall/trauma, pain
• Perilunate dislocation most common PE: Tenderness, instability
• Greater arc injury = transosseous injury XR: Disruption of carpal arches,
• Lesser arc injury = ligamentous injury lunate abnormality (angle &/or
position)

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 177

5 Forearm • DISORDERS Kienböck’s Disease

Rheumatoid Arthritis

Radiograph shows cartilage thinning at proximal Radiograph of wrist shows characteristic
interphalangeal joints, erosion of carpus and sclerosis of lunate
wrist joint, osteoporosis, and finger deformities

DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT

DEGENERATIVE/ARTHRITIC CONDITIONS

• Primary osteoarthritis in the wrist is uncommon. It is usually posttraumatic (distal radius/scaphoid fx or lig. injury).

Scapholunate Advanced Collapse (SLAC)

• Wrist arthritis due to Hx: Prior trauma/fall (often XR: 4 stages. DJD at: I. Styloidectomy & STT
posttraumatic scaphoid untreated), pain I. Rad. styloid & scaphoid fusion
flexion deformity (SL liga- PE: ϩ/Ϫ decreased ROM II. Radioscaphoid joint
ment injury or scaphoid with pain, tenderness to III. Capitolunate joint II. Proximal row carpectomy
fracture [SNAC]) palpation IV. Capitate migration or scaphoidectomy &
(radiolunate joint is 4 corner (lun., tri., cap.,
• Arthritis progresses over spared) ham.) fusion
four stages (I-IV)
III. 4 corner fusion
IV. Wrist arthrodesis (fusion)

Rheumatoid Arthritis

• Inflammatory disorder at- Hx: Pain (esp. in AM), stiff- XR: Wrist series. Depends 1. Medical management
tacks synovium and de- ness, deformity on severity. Mild degen- 2. Synovectomy
stroys joint PE: Swelling, deformity (vo- eration to destruction of 3. Tendon transfers
lar, ulnar translation of the joint. 4. Wrist fusion or arthro-
• Radiocarpal (supination carpus) LABS: RF, ANA, ESR
&, ulnar volar translation) plasty
& DRUJ (ulna subluxates
dorsally) affected

Kienböck’s Disease

• Osteonecrosis of the Hx: Pain, stiffness, and dis- XR: Stage I: Normal x-ray; Stage:
lunate ability of wrist II: Lunate sclerosis I: Immobilization
PE: Lunate/proximal row IIIA: Lunate fragmented I-IIIA: Radial shortening
• Etiology: traumatic or re- tenderness, decreased IIIB: IIIA ϩ scaphoid IIIB: STT fusion or proximal
petitive microtrauma to ROM, decreased grip flexed
lunate strength IV. DJD of adjacent joints row carpectomy (PRC)
IV: Wrist fusion or PRC
• 4 radiographic stages MR: Needed to dx stage I
• Associated with ulnar

negative variance of wrist

178 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

PEDIATRIC DISORDERS • Forearm 5

Madelung’s Deformity

Dorsal view of hand Prominence of ulnar Radiograph shows ulnar inclination of Lateral radiograph
reveals prominence demonstrates dorsal
of ulnar heads head, palmar deviation articular surfaces of distal radius, wedging prominence of ulnar
head with palmar
of hand, and bowing of of carpal bones into resulting space, and deviation of carpal
bones
forearm clearly seen on bowing of radius

radial view

Radial Club Hand

Osteology
of ulna

Kirschner
wire

Short, bowed forearm with marked Centralization
radial deviation of hand. Thumb absent. procedure
Radiograph shows partial deficit of radial
ray (vestige of radius present). Scaphoid,
trapezium, and metacarpal and phlanges
of thumb absent.

DESCRIPTION EVALUATION TREATMENT

MADELUNG’S DEFORMITY

• Deformity of the distal radius Hx: Pain in wrists & deformity Asymptomatic: observation and/or
• Volar ulnar physis disrupted causes PE: Deformity & prominent ulna head activity modification
XR: Distal radius deformity (incr. tilt & Symptomatic: radial osteotomy ϩ/Ϫ
increased volar tilt & radial inclination) & dorsal ulna sublux- ulna recession
inclination ation
• Ages 6-12; femalesϾmales

RADIAL CLUB HAND (RADIAL HEMIMELIA)

• Failure of formation (partial or com- Hx/PE: Bowing of forearm, radial de- 1. Elbow ROM (no surgery if stiff)
plete: stages I-IV) of the radius viation of hand 2. Hand centralization (age 1)
XR: Radius short or absent, bowed
• Associated with syndromes (TAR, ulna
VATER)

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 179

5 Forearm • SURGICAL APPROACHES

Posterior Approach to Forearm Supinator Brachialis

Incision site with Superficial Brachioradialis
arm in supination branch
of radial
Radius nerve

Ulna Periosteum Biceps brachii
Ulna (opened) Biceps aponeurosis

Biceps tendon
Flexor carpi radialis
Pronator teres

Radial artery Pronator teres
Brachioradialis
Supinator Flexor carpi
radialis

Flexor pollicis Flexor Superficial
longus digitorum radial nerve
sublimis
Radius Radius

Deep dissection done Ulna
with forearm in pronation
Forearm in
pronation

USES INTERNERVOUS PLANE DANGERS COMMENT

• ORIF of fractures FOREARM: ANTERIOR APPROACH (HENRY) • Most commonly only a
• Osteotomy portion of the incision is
• Biopsy & bone Proximal • Radial artery needed/used
‫ ؠ‬Brachioradialis (radial) • Superficial radial nerve
tumors ‫ ؠ‬Pronator teres (median) • Posterior interosseous • Proximally, must ligate the
radial recurrent artery
• ORIF of fractures Distal nerve (PIN)
• Wrist fusion or car- ‫ ؠ‬Brachioradialis (radial) • Distally, must detach prona-
‫ ؠ‬FCR (median) tor quadratus to get to dis-
pectomy tal radius
• Tendon repair WRIST: DORSAL APPROACH
• If needed, a compartment
• ORIF (e.g., distal ra- • No internervous plane • Superficial radial nerve other than the 4th can be
dius, scaphoid) (muscles all innervated by • Radial artery opened
radial nerve [PIN])
• Carpal tunnel re- • The capsular sensory
lease • 4th dorsal compartment is branch of the PIN is in the
opened & tendons are 4th compartment
• Tendon repair retracted
• Incise transverse carpal lig-
WRIST: VOLAR APPROACH ament to access volar wrist
capsule/bones
Proximal (same as Henry) • Median nerve
‫ ؠ‬Brachioradialis (radial) ‫ ؠ‬Palmar cutaneous br. • Must detach pronator
‫ ؠ‬FCR (median) ‫ ؠ‬Motor recurrent branch quadratus to expose distal
radius
Distal (over wrist & palm) • Superficial palmar arch
‫ ؠ‬None

180 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

SURGICAL APPROACHES • Forearm 5

Dorsal Approach to Wrist Joint

Incision Extensor tendons
site (retracted)

Radius Ulna

Radius Ulna
Hamate
Scaphoid
Trapezium
Capitate

Volar Approach to Wrist Joint

Incision Flexor tendons (retracted)
site

Median
nerve

Pisiform

Triquetrum Scaphoid
Lunate
Flexor
tendons Pronator
quadratus
Volar Transverse
capsule carpal ligament
(opened) (divided)

Lunate Radius
Scaphoid
Capitate

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 181

5 Forearm • SURGICAL APPROACHES

Midcarpal radial Midcarpal ulnar
1-2 6R
3-4 6U
4-5
Distal radioulnar

PORTAL LOCATION DANGERS COMMENT

WRIST ARTHROSCOPY PORTALS

• Uses: Diagnostic, TFCC tears, synovectomy, assist in fracture fixation, loose body removal, chondral lesions
• Portals are named for relation to the dorsal extensor wrist compartments (R & U indicate radial or ulnar side of tendon).

1-2 Between APL & ECRL 1. Deep branch of radial art. • Use is limited b/c of close proximity to

tendons. Distal to ra- 2. Superficial radial n. brs. & risk of neurovascular injury

dial styloid 3. Lat. antebrachial cut. brs. • Shows distal scaphoid & radial styloid

3-4 Between EPL & EDC None (PIN capsular br. in 4th • The “workhorse” portal of arthroscopy

tendons, 1cm distal to comp) • Shows SL interosseous lig., ligament of

Lister’s tubercle Testut (RSL), distal radius fossae

4-5 Between EDC & EDQ None • Shows radial TFCC attachment, LT interos-
tendons seous ligament

6R Radial side of ECU ten- Dorsal cutaneous br. ulnar n. • Shows ulnar insertion of TFCC, UT, & UL

don (b/w EDQ & ECU) ligaments, prestyloid recess

6U Ulnar side of ECU Dorsal cutaneous br. ulnar n. • Similar to 6R. Used less due to risk of

tendon nerve injury. Can be used for outflow.

Midcarpal 1cm distal to 3-4 por- None • Distal scaphoid, proximal capitate, SL liga-
radial tal, along radial border ment, STT articulation
of 3rd MC

Midcarpal 1cm distal to 4-5 por- None • Lunotriquetral joint, LT ligament, triquetro-
ulnar tal, in line with 4th MC hamate articulation

Other portals: Midcarpal: STT and triquetrohamate. Distal radioulnar: proximal and distal to ulnar head.

FASCIOTOMIES

See page 169.

182 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

Topographic Anatomy CHAPTER 6
Osteology
Radiology Hand
Trauma
Tendons 184
Joints 185
Other Structures 186
Minor Procedures 187
History 190
Physical Exam 192
Origins and Insertions 196
Muscles 199
Nerves 200
Arteries 201
Disorders 206
Pediatric Disorders 207
Surgical Approaches 210
212
213
216
218

6 Hand • TOPOGRAPHIC ANATOMY

Common names Anterior view
of digits

1 Thumb
2 Index
3 Middle
4 Ring
5 Little

Flexor carpi
radialis tendon

Thenar eminence Palmaris longus
tendon
Radial longitudinal
crease

Posterior view

Distal 1 Flexor digitorum
palmar superficialis tendons
crease
Flexor carpi ulnaris tendon

Hypothenar eminence
2 Proximal palmar crease

3 Proximal digital crease
Middle digital crease
Site of 4 5 Distal digital crease

metacarpophalangeal

joint

Extensor pollicis Anatomic
longus tendon snuff box

Site of thumb 1
carpometacarpal
joint

Extensor indicis Ulnar styloid
tendon

2 Extensor digitorum tendons

Site of Site of proximal
metacarpophalangeal interphalangeal (PIP) joint
joint 3
Site of distal
45 interphalangeal (DIP) joint

STRUCTURE CLINICAL APPLICATION
Palmaris longus tendon Not present in all people. Can be used for tendon grafts.
Anatomic snuffbox Site of scaphoid. Tenderness can indicate a scaphoid fracture.
Thumb carpometacarpal joint Common site of arthritis and source of radial hand pain.
Thenar eminence Atrophy can indicate median nerve compression (e.g., carpal tunnel syndrome).
Hypothenar eminence Atrophy can indicate ulnar nerve compression (e.g., ulnar or cubital tunnel syndrome).
Proximal palmar crease Approximate location of the superficial palmar arch of the palm.
Distal palmar crease Site of metacarpophalangeal joints on volar side of hand.

184 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

OSTEOLOGY • Hand 6

Scaphoid Lunate
Triquetrum
Carpal and
Pisiform
bones Tubercle Carpal
Capitate bones
Trapezium Hamate and
Hook
and

Tubercle 1

Trapezoid

Sesamoid 2 Base Right hand:
bones 34 Shafts Metacarpal bones anterior (palmar) view
5 Head

Base
Shafts Proximal phalanges
Head

Base
Shafts Middle phalanges

Head

Base Distal
Shafts phalanges

Tuberosity
Head

Lunate Carpal
Scaphoid bones

Capitate

Trapezoid

Pisiform Trapezium
Triquetrum
Carpal bones Hamate

Metacarpal bones Base 5 43 1
Shafts 2
Head

Proximal phalanges Base
Shafts
Right hand: Head
posterior (dorsal) view
Base

Middle phalanges Shafts

Head

Base

Distal Shafts

phalanges Tuberosity

Head

CHARACTERISTICS OSSIFY FUSE COMMENT

METACARPALS

• Triangular in cross section: gives Primary: body 9wk 18yr • Named I-V (thumb to small
2 volar muscular attachment sites (fetal) finger)
Secondary 2yr 18yr
• Thumb MC has saddle-shaped base: epiphysis • Only one physis per bone in the
increases it mobility head; base in thumb MC

PHALANGES

• Volar surface is almost flat Primary: body 8wk 14-18yr • 3 in each digit except thumb
(fetal) (two)
• Tubercles and ridges are sites for Secondary 2-3yr 14-18yr
attachment epiphysis • Only one physis per bone; it is in
the base

• Nomenclature for digits: thumb, index finger (IF), middle finger (MF), ring finger (RF), small/little finger (SF or LF), proxi-
mal phalanx (P1), middle phalanx (P2), distal phalanx (P3)

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 185

6 Hand • RADIOLOGY

X-ray, hand Lateral x-ray, finger
X-ray, finger
Distal Distal Middle finger Ring
interphalangeal phalanx finger
joint (DIP) (P3)
Small
Proximal Tuft finger
interphalangeal
joint (PIP) Middle
phalanx Index finger
Metacarpo- (P2)
phalangeal
joint Proximal
phalanx
Thumb (P1) Distal
interphalangeal
joint (IP) interphalangeal
joint (DIP)
CMC
Proximal
interphalangeal
joint (PIP)

X-ray, hand

Sesamoid Distal Distal
bone interphalangeal phalanx
joint (DIP) (P3)
Middle
Proximal phalanx
interphalangeal (P2)
joint (PIP)
Proximal
Metacarpal phalanx
neck (P1)

Metacarpal
base

RADIOGRAPH TECHNIQUE FINDINGS CLINICAL APPLICATION
AP (anteroposterior) Palm down on plate, beam Metacarpals, phalanges, Hand & finger fractures, hand
Lateral
Oblique perpendicular to plate CMC, MCP, and IP joints joint dislocations and DJD
Thumb stress view Ulnar wrist and hand on plate, Alignment of bones, joints Same as above

CT stagger finger flexion Alignment and position of Same as above
MRI Lateral with 40° rotation bones
Bone scan Thumb MCPJ under stress Evaluate ulnar collateral liga-
Abduct thumb at 0° & 30° of ment integrity (gamekeeper’s
flexion, beam at MCPJ thumb)

OTHER STUDIES Fractures (esp. scaphoid, hook
of hamate), nonunions
Axial, coronal, and sagittal Articular congruity, bone Occult fractures (e.g., scaph-
healing, bone alignment oid), ligament/tendon injuries
Infection, stress fxs, tumors
Sequence protocols vary Soft tissues (ligaments,
tendons), bones

All bones evaluated

186 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

TRAUMA • Hand 6

Metacarpal Fractures

Transverse fractures of metacarpal shaft usually
angulated dorsally by pull of interosseous muscles

In fractures of metacarpal neck, volar cortex often Oblique fractures tend to shorten and
comminuted, resulting in marked instability after rotate metacarpal, particularly in index
reduction, which often necessitates pinning and little fingers because metacarpals
of middle and ring fingers are stabilized
by deep transverse metacarpal ligaments

Fracture of Base of Metacarpals of Thumb

1st metacarpal

Bone fragment

Trapezium

Abductor pollicis
longus tendon

Type I (Bennett fracture). Intraarticular fracture Type II (Rolando fracture).
with proximal and radial dislocation of 1st meta- Intraarticular fracture with
carpal. Triangular bone fragment sheared off Y-shaped configuration

Fracture of Proximal Phalanx

Reduction of fractures of phalanges or metacarpals requires correct rotational as well as longitudinal
alignment. In normal hand, tips of flexed fingers point toward tuberosity of scaphoid, as in hand at left.

DESCRIPTION EVALUATION CLASSIFICATION TREATMENT

METACARPAL FRACTURES

• Common in adults, usually a fall Hx: Trauma, pain, swell- By location: • Nondisplaced: cast
or punching mechanism ing,ϩ/Ϫ deformity
PE: Swelling, tenderness. • Head • Displaced: reduce
• 5th MC most common (boxer fx) Check for rotational de- ‫ ؠ‬Stable: cast
• Thumb MC base fractures: dis- formity. Check neurovas- • Neck (most common) ‫ ؠ‬Unstable: CR-PCP
cular integrity. vs. ORIF
placed, intraarticular fractures XR: Hand. Evaluate for an- • Shaft (transverse, spiral) ‫ ؠ‬Shortened: ORIF
problematic gulation & shortening
‫ ؠ‬Bennett’s fx: APL deforms fx CT: Useful to evaluate for • Base • Intraarticular
‫ ؠ‬Rolando’s fx: can lead to DJD nonunion of fracture ‫ ؠ‬Thumb MC ‫ ؠ‬Head: ORIF
• 4th & 5th MCs can tolerate ‫ ؠ‬Bennett: volar lip fx ‫ ؠ‬Thumb base:
some angulation, 2nd & 3rd ‫ ؠ‬Rolando: commi- ‫ ؠ‬Bennett:
cannot nuted CR-PCP
‫ ؠ‬Small finger MC: ‫ ؠ‬Rolando: ORIF
“Baby Bennett”

COMPLICATIONS: Nonunion/malunion, grip strength deficiency, posttraumatic osteoarthritis (esp. Rolando fractures)

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 187

6 Hand • TRAUMA

Phalangeal Fractures

Extraarticular oblique shaft Intraarticular phalangeal base Intraarticular condyle fractures.
(diaphysis) fracture. fracture. Intraarticular fractures Fractures of distal phalanx
of phalanx that are non-
displaced and stable may
be treated with buddy
taping, careful observation,
and early active exercise.

Fracture dislocation B
of middle phalanx.

AC D

Types of fractures.
A. Longitudinal
B. Nondisplaced transverse
C. Angulated transverse
D. Comminuted

Extension block splint useful for fracture dislocation of proximal

DESCRIPTION EVALUATION CLASSIFICATION TREATMENT

PHALANGEAL FRACTURES

• Common injury Hx: Trauma, pain, Description: • Extraarticular:
• Mechanism: jamming, crush, swelling, ϩ/Ϫ deformity • Intra- vs extraarticular ‫ ؠ‬Stable: buddy tape/
• Displaced/ splint
or twisting PE: Swelling, tenderness. ‫ ؠ‬Unstable: CR-PCP vs
• Distal phalanx most common Check for rotational de- nondisplaced ORIF
• Stiffness is common prob- formity. Check neurovas- • Transverse, spiral,
cular integrity. • Intraarticular: ORIF
lem; early motion and occu- XR: Hand. Evaluate for oblique • Middle phalanx volar
pational therapy needed for angulation & shortening Location:
best results CT: Useful to evaluate for • Condyle base fx:
• Intraarticular fractures can nonunion of fracture • Neck ‫ ؠ‬Stable: extension block
lead to early osteoarthritis • Shaft/diaphysis
• Nail bed injury common w/ • Base splint
tuft (distal phalanx) fx • Tuft ‫ ؠ‬Unstable: ORIF
• Tuft fx: irrigate wound,
repair nail bed as
needed, splint fx/digit

COMPLICATIONS: Stiffness/loss of range of motion (esp. intraarticular fractures), nonunion/malunion, osteoarthritis

188 NETTER’S CONCISE ORTHOPAEDIC ANATOMY

TRAUMA • Hand 6

Gamekeeper’s thumb Mallet finger

Torn ulnar Adductor pollicis m. A. Tendon torn from A
collateral and its insertion. B. Bone B
ligament aponeurosis (cut) fragment avulsed with
tendon. In A and B
there is a 40°- 45°
flexion deformity
and loss of active
extension

Ruptured ulnar
collateral ligament
of metacarpopha-
langeal joint of
thumb

Jersey finger Splinted Mallet Finger

Flexor digitorum profundus tendon may be torn directly from
distal phalanx or may avulse small or large bone fragment.

DESCRIPTION Hx & PE WORKUP/FINDINGS TREATMENT

MALLET FINGER—EXTENSOR DIGITORUM AVULSION

• Rupture of extensor tendon Hx: “Jammed” finger; XR: Hand series. Look for 1. DIPJ extension splint,
from distal phalanx pain, DIPJ deformity bony avulsion (EDC) fx 6wk for most injuries
PE: Extensor lag at DIPJ; from dorsal base of P3
• Soft tissue or bony form inability to actively ex- in bony form of injury 2. Bony mallet with DIPJ
• Mech: jamming finger tend DIPJ subluxation: consider
PCP vs ORIF

JERSEY FINGER—FLEXOR DIGITORUM PROFUNDUS AVULSION

• FDP tendon rupture from P3 Hx: Forced DIPJ exten- XR: Hand series. Look for Leddy classification: Type:
• Mech: forced extension sion, injury; pain avulsion fracture from • 1: to palm. Early repair
PE: Inability to flex DIPJ volar base of P3. May • 2: to PIPJ. Repair Ͻ6wk
against a flexed finger (Ϫprofundus test) be retracted to finger/ • 3: bony to A4: ORIF
• Tendon retracts variably palm.

GAMEKEEPER’S THUMB

• Thumb MCP joint proper ul- Hx: Pain, decreased grip XR: Hand; r/o avulsion fx • Incomplete tear (sprain)
nar collateral ligament injury PE: Pain & laxity of Stress Fluoro: Can com- or no Stenor lesion:
MCPJ at 30° of flexion, splint 4-6wk
• Mech: forced radial deviation ϩ/Ϫ palpable mass pare side to side asym.
• Often a ski pole injury (Stenor lesion) MR: If diagnosis is un- • Complete tear or Stenor
clear lesion: primary repair

• Stenor lesion: when adductor aponeurosis falls under torn ulnar collateral ligament, producing a palpable mass/bump
• Stress testing of the thumb MCP in extension tests the accessory collateral ligament and volar plate integrity

NETTER’S CONCISE ORTHOPAEDIC ANATOMY 189