Palmar arching is further increased when flexor carpi ulnaris (which is attached to the pisiform) and intrinsic hand muscles attached to the transverse carpal ligament acts on the arch system.
The pisiform bone may be known by its small size, and by its presenting a single articular facet.
The ligaments connecting the pisiform bone are the articular capsule and the two volar ligaments.
The "volar surface" presents, on its medial part, an oval facet, for articulation with the pisiform; its lateral part is rough for ligamentous attachment.
Some reliable sesamoid bones (e.g., pisiform) are counted, while others (e.g., hallux sesamoids) are not.
The pisiform and triquetrum are pushed in a palmar to dorsal direction.
The articular capsule is a thin membrane which connects the pisiform to the triangular; it is lined by synovial membrane.
In this context the pisiform is regarded as a sesamoid bone embedded in the tendon of the flexor carpi ulnaris.
