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
Carpal bones 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: In this context the pisiform is regarded as a sesamoid bone embedded in the tendon of the