Anatomy Atlas

Wrist joint

Articulatio radiocarpalis
Also: Radiocarpal joint
JointHigh-yielddraftMSK

Condyloid joint between the distal radius (and articular disc) and the proximal carpal row. It's a common site of fractures, instability and tenosynovitis.

Core anatomy

Location

Between the distal forearm and the carpus.

Classification

Synovial condyloid (ellipsoid), biaxial joint.

Articulating surfaces

Distal radius and the articular disc of the triangular fibrocartilage complex (TFCC) proximally, with the scaphoid, lunate and triquetrum distally. The ulna does not articulate directly with the carpus; the articular disc separates it.

Capsule

Fibrous capsule reinforced by the palmar and dorsal radiocarpal ligaments and the ulnar and radial collateral ligaments.

Ligaments
  • Palmar radiocarpal and palmar ulnocarpal ligaments (strong)
  • Dorsal radiocarpal ligament
  • Radial and ulnar collateral ligaments of the wrist
  • Scapholunate and lunotriquetral interosseous ligaments (key to carpal stability)
  • TFCC: articular disc, radioulnar ligaments and ulnocarpal ligaments; stabilizes the DRUJ and cushions the ulnar carpus
Movements
  • Flexion and extension (shared with the midcarpal joint)
  • Abduction (radial deviation) and adduction (ulnar deviation)
  • Circumduction
Stability

Carpal ligaments, the TFCC and the tendons crossing the wrist.

Innervation

Anterior interosseous branch of the median nerve, posterior interosseous branch of the radial nerve, and dorsal and deep branches of the ulnar nerve

Blood supply

Dorsal and palmar carpal arches from the radial artery and ulnar artery

Relations

Volar: the carpal tunnel (median nerve and flexor tendons) and Guyon's canal (ulnar nerve and artery). Dorsal: the extensor tendons in six compartments; the first compartment (APL, EPB) is the site of de Quervain tenosynovitis. Radial: the anatomical snuffbox with the radial artery.

Carpal bones (right hand, palmar view)Palmar view of the right wrist with the thumb on the left. The proximal row, from lateral to medial, is the scaphoid, lunate, triquetrum and pisiform; the distal row is the trapezium, trapezoid, capitate and hamate. The radius articulates with the scaphoid and lunate; the ulna is separated from the carpus by the triangular fibrocartilage complex. The flexor retinaculum spans from the scaphoid tubercle and trapezium to the pisiform and hook of hamate, roofing the carpal tunnel, through which the median nerve passes. The ulnar nerve passes through Guyon canal, between the pisiform and the hook of hamate, superficial to the retinaculum.SLTPTTCHScaphoidmost fractured carpal; snuffboxtenderness; proximal pole AVN riskTrapeziumTrapezoidMedian nerve (in the tunnel)Flexor retinaculum(roof of the carpal tunnel)Radiusradial styloid is the more distalLunatemost dislocated carpal (palmar);AVN = Kienböck diseaseTriquetrumPisiform (sesamoid in FCU)CapitateHamateHook of hamate: fractures ingolf, baseball; Guyon canal edgeTFCC (triangular fibrocartilage)UlnaUlnar nerve (Guyon canal,between pisiform and hook)Right hand, palmar view · thumb ←Not to scaleLateral → medial: proximal row S L T P,distal row T T C H ("Some Lovers TryPositions That They Can't Handle")

Swipe sideways to see the whole diagram →

Carpal bones (right hand, palmar view). Thumb on the left. The flexor retinaculum (dashed) is anchored to the scaphoid tubercle and trapezium laterally and to the pisiform and hook of hamate medially, forming the roof of the carpal tunnel. Highlighted bones are the high-yield ones: scaphoid (fracture), lunate (dislocation) and hamate (hook fracture).
Original schematic, created for this atlas.
Anterior view of the wrist ligaments including the palmar radiocarpal ligament
Ligaments of the wrist, anterior (palmar) view.
Henry Vandyke Carter, Gray's Anatomy of the Human Body, 20th ed. (1918), Fig. 334. Source · Public domain (Public domain in the US: published before January 1, 1931 (per Wikimedia Commons))

Clinical correlations

De Quervain tenosynovitis PANCE

Mechanism / lesion

Stenosing tenosynovitis of the first dorsal compartment (abductor pollicis longus and extensor pollicis brevis) from repetitive thumb and wrist motion, e.g. new parents lifting infants.

Classic presentation

Radial-sided wrist pain and tenderness over the radial styloid, with a positive Finkelstein test.

Ganglion cyst PANCE

Mechanism / lesion

Mucin-filled cyst arising from a joint capsule or tendon sheath. It is the most common soft-tissue mass of the hand and wrist, most often dorsal over the scapholunate region.

Classic presentation

Smooth, firm, often transilluminating mass that may change in size. Usually painless or mildly painful.

Lunate and perilunate dislocation

Mechanism / lesion

High-energy hyperextension (fall from height, motor vehicle collision).

Classic presentation

Wrist pain and swelling. The volarly displaced lunate may compress the median nerve (acute carpal tunnel syndrome). Easily missed without a true lateral radiograph.

Kienböck disease

Mechanism / lesion

Avascular necrosis of the lunate, associated with negative ulnar variance (a short ulna).

Classic presentation

Dorsal wrist pain and stiffness. Progressive sclerosis and collapse of the lunate.

TFCC injury

Mechanism / lesion

Fall on an outstretched pronated hand, or degenerative (positive ulnar variance).

Classic presentation

Ulnar-sided wrist pain, clicking, worse with ulnar deviation and rotation.

High-yield PANCE pearls

  • De Quervain: APL + EPB (first dorsal compartment); Finkelstein positive; new parents.
  • Ganglion cyst: most common hand/wrist mass; dorsal; transilluminates.
  • Lunate dislocation → acute median nerve compression; "spilled teacup" on lateral X-ray.
  • Proximal row (lateral to medial): scaphoid, lunate, triquetrum, pisiform. Distal row: trapezium, trapezoid, capitate, hamate.

Imaging anatomy

X-ray

PA, lateral and oblique. PA: Gilula arcs (three smooth arcs along the carpal rows) should be unbroken; scapholunate gap (widening suggests scapholunate dissociation); ulnar variance. Lateral: the radius, lunate and capitate should be colinear. In lunate dislocation, the lunate tips volarly ("spilled teacup") and looks triangular on PA ("piece of pie").

CT

Occult carpal fractures and fracture characterization.

MRI

TFCC tears (MR arthrography improves sensitivity), ligament injuries, Kienböck disease, occult scaphoid fracture.

Ultrasound

Ganglion cysts (anechoic, well defined), de Quervain tenosynovitis (thickened first-compartment tendons and sheath), and guidance for injections.

Key views & landmarks
  • Wrist PA, lateral and oblique
  • Scaphoid view (PA ulnar deviation)
  • MR arthrogram for TFCC

Physical exam

Surface landmarks

Radial styloid, Lister's tubercle, ulnar head and styloid, anatomical snuffbox (scaphoid), pisiform (base of the hypothenar eminence), hook of hamate (in the hypothenar eminence, distal and radial to the pisiform), and the scaphoid tubercle (base of the thenar eminence).

Palpation

Palpate systematically radial → dorsal → ulnar → volar, including the snuffbox, first dorsal compartment, TFCC (ulnar fovea) and pisiform.

Strength / function testing

Active and passive flexion, extension, and radial and ulnar deviation. Grip strength.

Finkelstein test

Technique

The patient flexes the thumb into the palm and closes the fingers over it, then the examiner ulnarly deviates the wrist. (This commonly taught form is technically the Eichhoff maneuver; in Finkelstein's original, the examiner grasps the thumb and deviates the wrist.)

Positive test

Sharp pain over the radial styloid (first dorsal compartment).

Significance

De Quervain tenosynovitis. The commonly taught form produces false positives in normal wrists.

Ulnar fovea sign

Technique

Press into the soft spot between the ulnar styloid and FCU tendon, between the pisiform and the ulnar head.

Positive test

Tenderness reproducing the patient's pain.

Significance

Suggests a TFCC foveal tear or ulnotriquetral ligament injury. verify

Watson scaphoid shift test

Technique

The examiner presses on the scaphoid tubercle while moving the wrist from ulnar to radial deviation.

Positive test

Pain and/or a clunk.

Significance

Scapholunate instability.

Self-quiz

Q1.

A 31-year-old woman, 6 weeks postpartum, has pain over the radial side of her wrist when lifting her baby. Pain is reproduced when she makes a fist around her thumb and ulnarly deviates the wrist. Which tendons are involved?

Show answer

B

De Quervain tenosynovitis involves the first dorsal compartment: APL and EPB. EPL is in the third compartment, where it turns around Lister's tubercle.

Q2.

Which bones form the distal articular surface of the radiocarpal joint?

Show answer

A

The radius and articular disc articulate with the scaphoid, lunate and triquetrum. The pisiform sits on the triquetrum and isn't part of the radiocarpal joint.

Q3.

After a fall from a ladder, a patient has wrist pain and numbness of the thumb, index and middle fingers. The lateral radiograph shows the lunate tipped volarly, like a spilled teacup. Which nerve is at risk?

Show answer

B

A volarly dislocated lunate pushes into the carpal tunnel and compresses the median nerve (acute carpal tunnel syndrome). This is an orthopedic emergency.

Q4.

Kienböck disease is avascular necrosis of which bone, and which anatomic variant is associated with it?

Show answer

B

Kienböck disease is AVN of the lunate, associated with negative ulnar variance. Positive ulnar variance is associated with degenerative TFCC injury. Scaphoid AVN follows fracture.

Q5.

A 26-year-old has a smooth, firm, painless mass on the dorsal wrist over the scapholunate region. It transilluminates and varies in size. What is the most likely diagnosis?

Show answer

A

A ganglion cyst is the most common soft-tissue mass of the hand and wrist, usually dorsal over the scapholunate region. It is mucin-filled, arises from a joint capsule or tendon sheath, often transilluminates and changes in size.

Flashcards

See also