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Carpus

Carpals
Xray hand with color.jpg
Carpal bones.svg
There are eight carpal bones in each wrist
Distal row

E = Trapezium
F = Trapezoid
G = Capitate
H = Hamate
Proximal row

A = Scaphoid
B = Lunate
C = Triquetrum
D = Pisiform
Others

1 = Radius
2 = Ulna
3 = Metacarpus
Details
Identifiers
Latin ossa carpi
MeSH A02.835.232.087.144
TA A02.4.08.001
FMA 71335
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. This term derives its meaning from the Latin and the Greek (karpós), both 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.

In human anatomy, there are 8 carpal bones which can be classified as either belonging to two transverse rows, or three longitudinal columns.

The pair of rows together form an arch which is convex proximally and concave distally. On the palmar side, the carpus is concave, forming the carpal tunnel which is covered by the flexor retinaculum. Because the proximal row is simultaneously related to the articular surfaces of the radius and the distal row, it adapts constantly to these mobile surfaces. The bones of this row - scaphoid, lunate, and triquetrum - have their individual movements. The scaphoid contributes to the stability of the midcarpus as it articulates distally with the trapezium and the trapezoid. The distal row is more rigid as its transverse arch moves with the metacarpals.

Biomechanically and clinically, the carpal bones are better understood as arranged in three longitudinal columns:


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