The pisiform bone may be known by its small size, and by its presenting a single articular facet. It is situated on a plane anterior to the other carpal bones and is spheroidal in form.
Its dorsal surface presents a smooth, oval facet, for articulation with the triangular: this facet approaches the superior, but not the inferior border of the bone.
The volar surface 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, the latter usually convex.
The pisiform articulates with one bone, the triquetrum.