Skeleton of Hand

The human hand has 27 bones, not including the sesamoid bones which number varies between people. 14 of which are the phalanges (proximal, intermediate and distal) of the fingers. The metacarpals are the bones that connects the fingers and the wrist. Each human hand has 5 metacarpals and 8 carpal bones. The skeleton of the human hand consists of 27 bones: the eight short bones of the wrist or carpus organized into a proximal row (scaphoid, lunate, triquetral and pisiform), which articulates with the skeleton of the forearm, and a distal row (trapezium, trapezoid, capitate and hamate), which articulates with the bases of the metacarpal bones (i.e. the bones of the palm or "hand proper"). Together with the fourteen phalanx bones of the fingers these metacarpal bones form five rays or poly-articulated chains. Because supination and pronation (rotation about the axis of the forearm) are added to the two axes of movements of the wrist, the ulna and radius are sometimes considered part of the skeleton of the hand. There are numerous sesamoid bones in the hand, small ossified nodes embedded in tendons; the exact number varies between different people: whereas a pair of sesamoid bones are found at virtually all thumb metacarpophalangeal joints, sesamoid bones are also common at the interphalangeal joint of the thumb (72.9%) and at the metacarpophalangeal joints of the little finger (82.5%) and the index finger (48%). In rare cases, sesamoid bones have been found in all the metacarpophalangeal joints and all distal interphalangeal joints except that of the long finger. The articulations are: interphalangeal articulations of hand (the hinge joints between the finger bones) metacarpophalangeal joints (where the fingers meet the palm) intercarpal articulations (where the palm meets the wrist) wrist (may also be viewed as belonging to the forearm).

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