Wrist and Hand Anatomy – Review Flashcards

A comprehensive set of 70 question-and-answer flashcards summarising key anatomical structures, functions, nerve/vascular supply, movements, and clinical correlations of the wrist and hand.

How many carpal bones are found in each row of the wrist?

Four bones in the proximal row and four in the distal row (total of eight).

Name the bones in the proximal row of the carpus.

Scaphoid, lunate, triquetrum, pisiform (pisiform sits volar to triquetrum).

Name the bones in the distal row of the carpus.

Trapezium, trapezoid, capitate, hamate.

Which carpal bone is most commonly fractured and by what typical mechanism?

The scaphoid; usually fractured in a fall on an out-stretched hand (FOOSH).

Why can scaphoid fractures have a poor prognosis?

Its blood supply enters distally and flows proximally; a waist fracture can interrupt flow to the proximal fragment, predisposing to non-union or avascular necrosis.

Which bones articulate at the radiocarpal (wrist) joint?

The distal radius and TFCC with the scaphoid, lunate and triquetrum.

What primary motions occur at the radiocarpal joint?

Flexion/extension (dorsal extension–palmar flexion) and radial/ulnar deviation (abduction/adduction).

What movement takes place at the distal radioulnar joint (DRUJ)?

Forearm pronation and supination.

Which ligament resists ulnar deviation of the wrist?

Radial (lateral) collateral ligament.

Which ligament resists radial deviation of the wrist?

Ulnar (medial) collateral ligament.

How do the palmar radiocarpal ligaments act during forearm supination?

They become taut and carry the hand into supination with the forearm.

Which is weaker, the palmar or dorsal radiocarpal ligament?

The dorsal radiocarpal ligament is thinner/weaker.

What type of synovial joint is the thumb’s 1st carpometacarpal (CMC) joint?

A saddle joint (biaxial but allows opposition).

List the principle motions permitted at the 1st CMC joint.

Flexion, extension, abduction, adduction, opposition, and retroposition (small axial rotation).

How many phalanges does each finger possess?

Medial four fingers have three each (proximal, middle, distal); the thumb has two (proximal and distal).

What is the function of the digital pulley system (annular and cruciform ligaments)?

To keep flexor tendons close to bone, maintain a constant moment arm, and prevent bowstringing.

What condition involves fibrotic thickening of palmar fascia leading to flexion contracture of the ring and little fingers?

Dupuytren’s contracture (palmar fibromatosis).

What forms the roof of the carpal tunnel?

The flexor retinaculum (transverse carpal ligament).

Name the 10 structures traversing the carpal tunnel.

Four FDS tendons, four FDP tendons, flexor pollicis longus tendon, and the median nerve.

Which nerve runs through Guyon’s canal (Tunnel of Guyon) between pisiform and hook of hamate?

The ulnar nerve.

What is bowstringing and its mechanical consequence?

Separation of a tendon from the joint after pulley rupture; increases the moment arm but forces the muscle to shorten more, causing active insufficiency.

Define trigger finger (stenosing tenosynovitis).

Inflammation and swelling of tendon/synovium causing the flexor tendon to catch under a pulley, locking the digit.

List the muscles of the thenar eminence.

Abductor pollicis brevis, flexor pollicis brevis, opponens pollicis (plus adductor pollicis nearby).

Which nerve supplies most thenar muscles?

Recurrent branch of the median nerve (C8–T1).

Which thenar muscle is supplied by the ulnar nerve rather than the median?

Adductor pollicis (deep branch of ulnar nerve).

Name the muscles of the hypothenar eminence.

Abductor digiti minimi, flexor digiti minimi, opponens digiti minimi.

What nerve innervates the hypothenar muscles?

Deep branch of the ulnar nerve (C8–T1).

What actions are produced by the lumbrical muscles?

Flexion at the MCP joints with simultaneous extension at the PIP and DIP joints.

Describe the lumbricals’ nerve supply.

Lateral two (1st & 2nd) by the median nerve; medial two (3rd & 4th) by the deep branch of the ulnar nerve.

What does the mnemonic PAD/DAB refer to?

Palmar interossei ADduct the fingers; Dorsal interossei ABduct the fingers.

Which nerve innervates all interossei muscles?

Deep branch of the ulnar nerve (C8–T1).

What is a mallet finger injury?

Avulsion or rupture of the extensor tendon insertion at the base of the distal phalanx, resulting in an inability to extend the DIP joint.

Explain the pathology of a boutonnière deformity.

Rupture of the central slip of the extensor tendon at the middle phalanx causes PIP flexion and DIP hyperextension.

Describe the mechanism of a swan-neck deformity.

Rupture or laxity of the volar plate at the PIP joint causes PIP hyperextension and DIP flexion; often seen in rheumatoid arthritis.

Which intrinsic hand muscles are NOT supplied by the ulnar nerve?

Thenar muscles (except adductor pollicis) and the first and second lumbricals (supplied by median nerve).

Which arteries form the superficial palmar arch?

Primarily the ulnar artery with contribution from the superficial branch of the radial artery.

Which arteries form the deep palmar arch?

Primarily the radial artery, anastomosing with the deep branch of the ulnar artery.

Where is the radial artery palpated in the hand?

In the floor of the anatomic snuff box over the scaphoid and trapezium.

Before forming the deep palmar arch, which key branches does the radial artery give off?

Dorsal carpal branch, princeps pollicis artery, and radialis indicis artery.

At what point does the deep branch of the radial nerve become the posterior interosseous nerve?

After it passes the lower border of the supinator muscle in the proximal forearm.

What is ulnar variance and why is it clinically relevant?

The relative length of the ulna versus the radius at the wrist; positive or negative variance alters load distribution through the TFCC and can predispose to pathology.

State two main functions of the flexor retinaculum.

Forms the roof of the carpal tunnel and secures flexor tendons against the carpal bones to prevent bowstringing.

List the principal components of the TFCC aside from the articular disc.

Dorsal and palmar radioulnar ligaments, ulnolunate and ulnotriquetral ligaments, meniscus homolog, and ulnar collateral ligament.

Define active insufficiency in the context of bowstringing.

Because the tendon is displaced away from the joint, it must shorten more to achieve the same angular movement, reducing effective force output.

List the movements allowed at the metacarpophalangeal (MCP) joints.

Flexion, extension (and hyperextension), abduction, and adduction.

What movements are permitted at interphalangeal (IP) joints?

Flexion and extension only.

Outline the bony and ligamentous boundaries of the carpal tunnel.

Floor: concave carpal bones; Roof: flexor retinaculum; Radial border: scaphoid & trapezium tubercles; Ulnar border: pisiform & hook of hamate.

Which tendon runs just lateral to the carpal tunnel in a groove on the trapezium?

Flexor carpi radialis tendon.

What structures form the borders of the anatomic snuff box?

Laterally – tendons of abductor pollicis longus & extensor pollicis brevis; Medially – tendon of extensor pollicis longus; Floor – scaphoid & trapezium with radial artery.

Which injury is often called "Skier’s thumb"?

Rupture or sprain of the ulnar collateral ligament of the thumb’s MCP joint.

Which arteries give rise to the common palmar digital arteries?

The superficial palmar arch.

What vessels arise from the dorsal carpal arch?

Dorsal metacarpal arteries, which bifurcate into dorsal digital arteries.

Which nerve supplies cutaneous sensation to the palmar aspect of the lateral 3½ digits?

Median nerve.

Describe the two main layers of the palmar aponeurosis and their functions.

Superficial layer anchors skin for grip; deep layer blends with flexor retinaculum to help form the carpal tunnel and protect deeper structures.