Wrist
From Wikipedia, the free encyclopedia
| wrist joint | |
|---|---|
 |
|
| A human wrist. | |
| Latin | articulatio radiocarpalis |
| Gray's | subject #86 327 |
| MeSH | Wrist+joint |
| Dorlands/Elsevier | a_64/12161475 |
In human anatomy, the wrist is the flexible and narrower connection between the forearm and the hand. 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.
Contents |
[edit] 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 triangular 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.
[edit] 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]
[edit] Ligaments
The joint is surrounded by a capsule, strengthened by the following ligaments:
- Volar radiocarpal ligament
- Dorsal radiocarpal ligament
- Ulnar collateral ligament (thumb)
- Radial collateral ligament (thumb)
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.
[edit] Radiocarpal and midcarpal joints
The wrist usually refers to the "radiocarpal joint". However, the midcarpal joint, though not a true joint[2], is closely associated with many of the same actions. It represents the boundary between the two rows of bones in the carpus.
[edit] 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.
[edit] Accessorizing the wrist joint
Since the wrist is a convenient narrow part between the forearm and the hand, it is used for fashion and practical accessories such as watches, bracelets, and wristbands, and also for such things as handcuffs.
These are attached by either a closing device such as a buckle or Velcro, or by moving them over the hand, where they do not fall off due to elasticity of the strap. Most items worn around the wrist are designed to be conveniently attached and removed, whereas handcuffs are designed to be very difficult to remove without the appropriate key.
[edit] See also
- Distal radius fracture
- Brunelli Procedure, related to instability in the wrist
[edit] Additional images
 Right Human Posterior Distal Radius, Ulna, Carpals |
 Right Human Anterior Distal Radius, Ulna, Carpals |
 Carpus |
 Ligaments of wrist. Anterior view |
 Ligaments of wrist. Posterior view. |
[edit] References
- ^ Silverstein B, Welp E, Nelson N, Kalat J (1998). "Claims incidence of work-related disorders of the upper extremities: Washington state, 1987 through 1995.". Am J Public Health 88 (12): 1827-33. PMID 9842381.
- ^ Hand kinesiology at UK bone/midartic.html
[edit] External links
- Wrist ligaments at upenn.edu
- Dictionary at eMedicine wrist
- Dictionary at eMedicine wrist+joint
- Hand kinesiology at UK bone/wrist.html
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