Pisiform bone evolutionary benefits from having a shorter pisiform bone, including facilitating ulnar deviation of the hand and preventing hyperextension of the wrist, motions that improve the action of clubbing. Pisiform bone The pisiform bone ( or ), also spelled pisiforme (from the Latin "pisifomis", pea-shaped), is a small knobbly, sesamoid bone that is found in the wrist. It forms the ulnar border of the carpal tunnel. The pisiform is a sesamoid bone, with no covering membrane of periosteum. It is the last carpal bone to ossify. The pisiform bone is a small bone found in the proximal row of the wrist
Intercarpal joints the hamate, the other, the pisometacarpal ligament, joins the pisiform to the base of the fifth metacarpal bone. These ligaments are, in reality, prolongations of the tendon of the Flexor carpi ulnaris. These joints are also arthrodial joints connected by dorsal, volar, and interosseous ligaments. The dorsal ligaments are three in number, extend transversely from one bone to another on the dorsal surface, connecting the greater with the lesser multangular, the lesser multangular with the capitate, and the capitate with the hamate. The volar ligaments are also three and have a similar arrangement on the volar surface. The three interosseous