Orthopaedic Surgery - Wrist Anatomy and Exam

Basics

The wrist is a complex articulation formed by:

Eight carpal bones

arranged in:

Two rows.

These bones provide mobility while maintaining stability between the:

Forearm

and

Hand.

Carpal Bones

From radial to ulnar, the:

Proximal carpal row

contains:

Scaphoid

Lunate

Triquetrum

and

Pisiform.

Distal Carpal Row

From radial to ulnar, the:

Distal carpal row

contains:

Trapezium

Trapezoid

Capitate

and

Hamate.

Dorsal Extensor Compartments

The dorsal wrist contains:

Six extensor compartments

that transmit the extensor tendons from the forearm into the:

Hand and digits.

First Dorsal Compartment

The first and most radial compartment contains:

Abductor pollicis longus

and

Extensor pollicis brevis.

Clinical Significance of the First Compartment

These tendons form the:

Radial border of the anatomic snuffbox.

Stenosing tenosynovitis of this compartment produces:

de Quervain tenosynovitis.

de Quervain Tenosynovitis

In de Quervain disease, thickening and irritation of the first dorsal compartment restrict smooth tendon gliding and produce:

Radial-sided wrist pain

especially with:

Thumb motion

and

Ulnar deviation.

Second Dorsal Compartment

The second compartment lies radial to:

Lister tubercle

and contains:

Extensor carpi radialis longus

and

Extensor carpi radialis brevis.

Third Dorsal Compartment

The third compartment passes around the ulnar side of:

Lister tubercle

and contains:

Extensor pollicis longus.

Anatomic Snuffbox

The extensor pollicis longus forms the:

Ulnar border of the anatomic snuffbox.

The first dorsal compartment tendons form its:

Radial border.

EPL Rupture

The extensor pollicis longus may rupture in association with:

Rheumatoid arthritis

or following selected:

Distal radius fractures.

Fourth Dorsal Compartment

The fourth compartment lies just ulnar to the third and contains:

Four extensor digitorum tendons

and

Extensor indicis proprius.

Posterior Interosseous Nerve

The terminal posterior interosseous nerve lies deep to the extensor tendons in this region and contributes predominantly:

Articular sensory fibers

near the dorsal wrist.

Fifth Dorsal Compartment

The fifth compartment overlies the distal:

Radioulnar joint

and contains:

Extensor digiti minimi.

Sixth Dorsal Compartment

The sixth compartment contains:

Extensor carpi ulnaris.

It lies adjacent to the:

Ulnar head

and

Ulnar styloid.

ECU Abnormality

The ECU tendon may become:

Inflamed

Subluxated

or

Ruptured.

In rheumatoid arthritis, attritional tendon injury may occur because of:

Distal radioulnar joint disease.

Volar Wrist Compartments

Important volar passages include the:

Carpal tunnel

and

Guyon canal.

These transport major:

Tendons

Nerves

and

Vessels

into the hand.

Diagnosis

Symptoms involving the wrist may originate locally or may be:

Referred from more proximal structures.

Referred Pain

Potential sources include:

Cervical disc disease

Cervical osteoarthritis

Brachial plexus disorders

and entrapment syndromes involving the:

Elbow

or

Shoulder region.

Pregnancy Considerations

Pregnancy is associated with an increased incidence of:

Carpal tunnel syndrome

because of:

Fluid retention

and increased pressure within the:

Carpal tunnel.

Postpartum de Quervain Disease

New mothers also have an increased incidence of:

de Quervain tenosynovitis

often associated with repetitive lifting and positioning of:

Infants.

History

A complete history should include:

Age

Hand dominance

Occupation

Sports or recreational activities

and previous:

Wrist injury or surgery.

Chief Complaint

Clarify whether the major problem is:

Pain

Weakness

Numbness

Stiffness

Instability

Clicking

or

Swelling.

Mechanism of Injury

For traumatic complaints, determine:

Direction of force

Position of the wrist

and whether the mechanism involved:

Fall

Twisting

Direct impact

or

Axial loading.

Symptom Characterization

Ask about:

Onset

Duration

Frequency

Activity relationship

Exacerbating factors

Relieving factors

and whether symptoms are worse:

At night

or during the:

Day.

Occupational History

Document:

Work demands

Current work status

and any relevant:

Workers’ compensation considerations.

Physical Examination

Examine both upper extremities whenever possible because:

Side-to-side comparison

is extremely useful.

General Observation

Observe spontaneous use of the hand and wrist during:

Conversation

Undressing

and routine:

Movement.

Smooth spontaneous motion suggests different pathology from guarded, stiff, or:

Jerky movement.

Entire Upper Extremity Examination

Because symptoms may be referred, the examination should include the:

Cervical spine

Shoulder

Elbow

Forearm

Wrist

and

Hand.

Skin Examination

Inspect for:

Warmth

Dryness

Swelling

Scars

Hair loss

and other skin:

Changes.

Warmth

Marked localized warmth may suggest:

Inflammation

or

Infection.

Anhidrosis

Abnormally dry skin may reflect impaired:

Autonomic nerve function.

Bony Palpation

Systematic palpation should include:

Radial styloid

Anatomic snuffbox

Scaphoid

Trapezium

Capitate

Lunate

Ulnar styloid

Triquetrum

Pisiform

and

Hook of the hamate.

Radial Styloid

The radial styloid is located at the distal:

Radial aspect of the wrist.

Tenderness here may occur with:

Radial styloid fracture

or nearby:

First-compartment tendon disease.

Anatomic Snuffbox

The anatomic snuffbox is the depression just distal and dorsal to the:

Radial styloid.

It becomes more obvious when the patient extends the:

Thumb.

Scaphoid

The scaphoid forms the floor of the:

Anatomic snuffbox.

It is the:

Most commonly fractured carpal bone.

Snuffbox Tenderness

Tenderness in the snuffbox after trauma raises concern for:

Scaphoid fracture.

A normal initial radiograph does not completely exclude this:

Diagnosis.

Trapezium

The trapezium lies radially and articulates with the:

First metacarpal

to form the thumb:

CMC joint.

Thumb CMC Arthritis

The thumb CMC joint is a common site of:

Osteoarthritis.

CMC Grind Test

The grind test evaluates for symptomatic:

First CMC arthritis.

The examiner stabilizes the trapezium and applies:

Axial compression

through the first metacarpal while rotating or translating the:

Metacarpal base.

Positive Grind Test

Reproduction of:

Pain

or

Crepitus

supports symptomatic:

CMC degeneration.

Capitate

The capitate is the:

Largest carpal bone.

It lies immediately proximal to the base of the:

Third metacarpal.

Lunate

The lunate lies proximal to the:

Capitate

and articulates proximally with the:

Radius.

Lunate Injury

The lunate is commonly involved in:

Perilunate and lunate dislocations

and may also sustain:

Fracture or osteonecrosis.

Central Wrist Alignment

The:

Third metacarpal

Capitate

and

Lunate

normally align along the central axis of the:

Wrist.

ECRB Relationship

The:

Extensor carpi radialis brevis

inserts at the base of the:

Third metacarpal.

Ulnar Styloid

The ulnar styloid is palpable at the distal:

Ulna.

The ECU tendon passes nearby in a groove along the:

Distal ulna.

Triquetrum

The triquetrum lies distal to the:

Ulnar styloid

within the proximal:

Carpal row.

Pisiform

The pisiform is a sesamoid bone contained within the:

Flexor carpi ulnaris tendon.

Guyon Canal

The pisiform forms the:

Ulnar border

of the entrance to:

Guyon canal.

Hook of Hamate

The hook of the hamate lies distal and radial to the:

Pisiform.

It forms the:

Radial border

of Guyon canal.

Contents of Guyon Canal

Guyon canal transmits the:

Ulnar nerve

and

Ulnar artery

into the hand.

Palmar Wrist Examination

Important structures on the volar wrist include:

Palmaris longus

Carpal tunnel

Flexor carpi radialis

and the:

Radial and ulnar arteries.

Palmaris Longus

The palmaris longus tendon, when present, lies superficially near the:

Midline of the volar wrist.

It is congenitally absent in a substantial proportion of:

Individuals.

Palmaris Longus Examination

To make the tendon prominent, ask the patient to:

Oppose the thumb and small finger

while lightly flexing the:

Wrist.

Carpal Tunnel

The carpal tunnel is a:

Fibro-osseous canal

on the volar side of the wrist.

Carpal Tunnel Boundaries

Its floor and walls are formed by the:

Carpal bones

while the roof is formed by the:

Transverse carpal ligament.

Carpal Tunnel Landmarks

Proximally, important landmarks include the:

Pisiform

and

Scaphoid tubercle.

Distally, the ligament attaches near the:

Hook of hamate

and

Trapezial tubercle.

Carpal Tunnel Contents

The tunnel contains the:

Median nerve

and

Nine flexor tendons

consisting of:

Four FDS tendons

Four FDP tendons

and

Flexor pollicis longus.

Carpal Tunnel Syndrome

Compression of the median nerve within this tunnel produces:

Carpal tunnel syndrome.

Sensory Symptoms

Patients typically experience numbness or paresthesias involving the:

Thumb

Index finger

Middle finger

and

Radial half of the ring finger.

Nocturnal Symptoms

Symptoms frequently worsen:

At night.

Motor Effects

Advanced compression may produce:

Thenar weakness

and, in severe cases,

Thenar atrophy.

Tinel Sign

Percussion over the median nerve at the volar wrist may produce:

Tingling or electrical sensations

in the median nerve:

Distribution.

Phalen Test

The Phalen maneuver involves maintaining maximal:

Wrist flexion

to provoke median nerve:

Paresthesias.

Flexion-Compression Test

Adding direct pressure over the:

Carpal tunnel

during wrist flexion may reproduce symptoms more quickly.

Symptoms developing within approximately:

30–60 seconds

support:

Median neuropathy at the wrist.

Flexor Carpi Radialis

The FCR tendon travels along the:

Radial volar wrist

and inserts primarily at the base of the:

Second metacarpal.

FCR Tendinitis

FCR tendinopathy may produce pain along the:

Volar-radial wrist.

FCR Examination

Pain may be reproduced by:

Palpation of the FCR tunnel

Resisted wrist flexion

and

Resisted radial deviation.

Radial Artery

The radial artery is palpable just radial to the:

Flexor carpi radialis tendon.

Ulnar Artery

The ulnar artery can be palpated near the:

Pisiform

as it enters the:

Hand.

Vascular Dominance

The relative contribution of the radial and ulnar arteries varies between:

Individuals.

Before procedures that may compromise one vessel, collateral circulation should be assessed when:

Clinically relevant.

Range of Motion

Range of motion should be evaluated first:

Actively

and then:

Passively.

Wrist Flexion

Normal wrist flexion is approximately:

70–80°.

Wrist Extension

Normal wrist extension is approximately:

70–80°.

Radial Deviation

Normal radial deviation is approximately:

20°.

Ulnar Deviation

Normal ulnar deviation is approximately:

30°.

Supination

Normal forearm supination is approximately:

90°.

Pronation

Normal forearm pronation is approximately:

90°.

Neurologic Examination

The neurologic examination should evaluate both:

Motor function

and

Sensation.

Motor Testing

Important myotomal functions include:

Wrist extension — predominantly C6

Wrist flexion — predominantly C7

Supination — C5–C6

and

Pronation — primarily C6–C7 with contributions from lower roots depending on the muscle tested.

Peripheral Nerve Examination

Test motor and sensory function of the:

Median nerve

Ulnar nerve

and

Radial nerve.

Sensory Testing

Useful autonomous sensory regions include:

Median nerve — volar index fingertip

Ulnar nerve — small fingertip

and

Radial nerve — dorsal first web space.

Provocative Maneuvers

Special tests help localize pathology involving:

Tendons

Ligaments

and

Peripheral nerves.

Finkelstein and Eichhoff Maneuvers

These maneuvers are used to assess:

de Quervain tenosynovitis.

Eichhoff Test

The commonly performed maneuver in which the patient places the thumb inside a closed fist and the examiner ulnarly deviates the wrist is more accurately called the:

Eichhoff test.

Positive Test

Sharp pain over the:

First dorsal compartment

supports the diagnosis of:

de Quervain tenosynovitis.

Scaphoid Shift Test

The:

Scaphoid shift test

also called the:

Watson test

assesses integrity of the:

Scapholunate ligament.

Watson Test Technique

The wrist begins in:

Ulnar deviation

and slight:

Extension.

The examiner places the thumb over the:

Scaphoid tubercle

and applies dorsal pressure while moving the wrist toward:

Radial deviation.

Positive Watson Test

With scapholunate ligament insufficiency, the scaphoid may:

Sublux dorsally

producing:

Pain

or a palpable:

Clunk.

Bilateral Comparison

Because some asymptomatic individuals have a positive maneuver, the test should be compared with the:

Contralateral wrist.

Midcarpal Shift Test

The midcarpal shift test evaluates for:

Midcarpal instability.

Technique

The forearm is stabilized in:

Pronation.

A volarly directed force is applied over the:

Capitate

while axially loading the wrist and moving it toward:

Ulnar deviation.

Positive Midcarpal Shift

A painful or reproducible:

Clunk

suggests:

Midcarpal instability.

Dorsal Midcarpal Translation

Dorsal translation of the capitate relative to the:

Lunate

may also be compared with the opposite:

Wrist.

Tinel Sign Elsewhere

Tinel testing can be performed over any accessible:

Peripheral nerve.

For example, percussion over the:

Ulnar nerve at the elbow

may reproduce symptoms in the:

Ulnar nerve distribution.

Imaging

Standard Radiographs

A standard wrist series should include at least:

Posteroanterior

Lateral

and

Oblique views.

Scaphoid View

A dedicated:

Scaphoid view

with the wrist in:

Ulnar deviation

can improve visualization of:

Scaphoid fractures.

Clenched-Fist View

A:

Clenched-fist stress view

can accentuate widening of the:

Scapholunate interval.

Comparison with the opposite wrist may be helpful when evaluating suspected:

Scapholunate ligament injury.

Occult Scaphoid Fracture

Scaphoid fractures may not be visible on initial:

Radiographs.

If clinical suspicion remains high, further evaluation may include:

Repeat radiographs

or

Advanced imaging.

Repeat Radiographs

Historically, repeat radiographs were often obtained after approximately:

7–10 days.

MRI or CT may establish the diagnosis:

Earlier.

Gilula Arcs

On a normal PA wrist radiograph, three smooth arcs known as:

Gilula lines

should be preserved.

First Gilula Arc

The first arc follows the proximal convex surfaces of the:

Scaphoid

Lunate

and

Triquetrum.

Second Gilula Arc

The second follows the distal concave surfaces of the:

Scaphoid

Lunate

and

Triquetrum.

Third Gilula Arc

The third follows the proximal surfaces of the:

Capitate

and

Hamate.

Disruption of Gilula Lines

Loss of these smooth arcs suggests:

Carpal malalignment

Fracture

or

Dislocation.

CT

CT is especially useful for:

Complex fracture assessment

and

Preoperative planning.

MRI

MRI is useful for evaluating:

Ligament tears

Tendon abnormalities

Occult fractures

Avascular necrosis

and

Soft-tissue masses.

Grip Strength

Grip strength provides an objective measure of:

Hand function.

It should be compared with the:

Contralateral side.

Pinch Strength

Pinch strength may also be measured serially to assess:

Thumb and hand function.

Clinical Summary

Key anatomy: The wrist contains 8 carpal bones in two rows and 6 dorsal extensor compartments.

Important landmarks: The scaphoid forms the floor of the anatomic snuffbox, the pisiform and hook of hamate border Guyon canal, and the transverse carpal ligament forms the roof of the carpal tunnel.

Carpal tunnel contents: The median nerve plus 9 flexor tendons.

Typical ROM: Flexion and extension about 70–80°, radial deviation about 20°, ulnar deviation about 30°, and pronation/supination about 90° each.

Key provocative tests: Eichhoff/Finkelstein for de Quervain disease, Watson scaphoid shift for scapholunate instability, midcarpal shift for midcarpal instability, and Phalen, flexion-compression, and Tinel for carpal tunnel syndrome.

Scaphoid concern: Snuffbox tenderness after trauma should raise suspicion for a scaphoid fracture, even if initial radiographs are normal.

Imaging: Standard wrist radiographs include PA, lateral, and oblique views; special views and CT or MRI are added according to suspected pathology.

Radiographic alignment: The three Gilula arcs should remain smooth and continuous; disruption suggests carpal injury or instability.

Key Principle

A systematic wrist examination should proceed from:

Inspection and palpation

to

Range of motion, neurologic testing, provocative maneuvers, and imaging.

The examiner should understand the relationships among the:

Carpal bones

Extensor compartments

Carpal tunnel

Guyon canal

and

Major neurovascular structures.

Because wrist symptoms may be referred from the:

Cervical spine, shoulder, elbow, or forearm, the entire upper extremity should be examined when the diagnosis is uncertain.

Accurate localization of:

Tenderness, instability, tendon pathology, nerve symptoms, and radiographic alignment

is the foundation of diagnosing common wrist disorders.