The pisiform bone (pisiforme or lentiform bone) is a small knobbly, pea-shaped bone of the wrist. It is found in the proximal row of the carpus, located where the ulna joins the carpus (wrist). This bone only articulates with the triquetral.
The pisiform bone is typically known by its small size, and by presenting a single articular facet. It is situated on a plane anterior to the other carpal bones and is spheroidal (spherical) in form. Pisiform is derivative of the Latin word “pisum” which means “pea.”
The palmar surface of the bone is rounded and rough and gives attachment to the transverse carpal ligament, and to the Flexor carpi ulnaris and Abductor digiti quinti. The lateral and medial surfaces are also rough, the former being concave, and the latter convex.
image Caption: (D) shows the Pisiform bone. Credit: Zoph/Wikipedia(CC BY-SA 3.0)