Wrist

In human anatomy, the wrist is the flexible and narrower connection between the forearm and the palm. The wrist is essentially a double row of small short bones, called carpals, intertwined to form a malleable hinge.

The wrist-joint (articulatio radiocarpea) is a condyloid articulation allowing three degrees of freedom.

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Structure of joint

The parts forming it are the lower end of the radius and under surface of the articular disk above; and the scaphoid, lunate, and triquetral bones below.

The articular surface of the radius and the under surface of the articular disk form together a transversely elliptical concave surface, the receiving cavity.

The superior articular surfaces of the scaphoid, lunate, and triquetrum form a smooth convex surface, the condyle, which is received into the concavity.

The bones of the wrist can be easily remembered by the Acronym SLTPTTCH - Some Lovers Try Positions That They Can't Handle. These represent the bones in order of proximal row lateral to medial and then distal row lateral to medial: Scaphoid Lunate Triqetrium Pisiform Trapezium Trapezoid Capitate Hamate.

Pathology

Due to its complexity, wrist injuries and dysfunctions are difficult to treat. With the dawn of the computer age, wrist and hand pain became the most common complaint involving the upper extremity. Hand and wrist injuries have a major economic impact through health care costs and workers' compensation claims.

A study of workers' compensation claims in Washington state from 1987 to 1995 demonstrated a higher incidence rate than any other musculoskeletal condition related to an industrial injury claim, and the average claim was around $7,500.^[1]

Ligaments

The joint is surrounded by a capsule, strengthened by the following ligaments:

• Palmar radiocarpal ligament
• Dorsal radiocarpal ligament
• Ulnar collateral ligament (wrist)
• Radial collateral ligament (wrist)

The synovial membrane lines the deep surfaces of the ligaments above described, extending from the margin of the lower end of the radius and articular disk above to the margins of the articular surfaces of the carpal bones below. It is loose and lax, and presents numerous folds, especially behind.

Movements

The movements permitted in this joint are flexion, extension, abduction, adduction, and circumduction. They are studied with those of the carpus, with which they are combined.

See also

• Distal radius fracture
• Brunelli Procedure, related to instability in the wrist

Additional images

References