Wrist bones
| Carpals | |
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| Details | |
| Identifiers | |
| Latin | ossa carpi |
| MeSH | D002348 |
| TA | A02.4.08.001 |
| FMA | 23889 |
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Anatomical terms of bone
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The carpal bones are the eight small bones that make up the wrist (or carpus) that connects the hand to the forearm. The term "carpus" is derived from the Latin and the Greek (karpós), meaning "wrist." In human anatomy, the main role of the wrist is to facilitate effective positioning of the hand and powerful use of the extensors and flexors of the forearm, and the mobility of individual carpal bones increase the freedom of movements at the wrist.
In tetrapods, the carpus is the sole cluster of bones in the wrist between the radius and ulna and the metacarpus. The bones of the carpus do not belong to individual fingers (or toes in quadrupeds), whereas those of the metacarpus do. The corresponding part of the foot is the tarsus. The carpal bones allow the wrist to move and rotate vertically.
The eight carpal bones may be conceptually organized as either two transverse rows, or three longitudinal columns.
When considered as paired rows, each row forms an arch which is convex proximally and concave distally. On the palmar side, the carpus is concave and forms the carpal tunnel, which is covered by the flexor retinaculum. The proximal row (comprising scaphoid, lunate, and triquetrum) articulates with the surfaces of the radius and distal carpal row, and thus constantly adapts to these mobile surfaces. Within the proximal row, each carpal bone has slight independent mobility. For example, the scaphoid contributes to midcarpal stability by articulating distally with the trapezium and the trapezoid. In contrast, the distal row is more rigid as its transverse arch moves with the metacarpals.
Biomechanically and clinically, the carpal bones are better conceptualized as three longitudinal columns:
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