Os pisiforme

Os Pisiforme

The os pisiforme is a small, pea-shaped bone located in the human wrist. It is one of the eight carpal bones that make up the wrist, and is part of the ulnar side of the wrist, which is the side of the little finger. The os pisiforme is unique among the carpal bones in that it is a sesamoid bone, meaning it is embedded within a tendon.

Anatomy

The os pisiforme is situated where the palm of the hand meets the wrist, on the ulnar side. It is embedded within the tendon of the flexor carpi ulnaris muscle, one of the muscles responsible for flexing the wrist. The bone is roughly pea-shaped, hence its name, which comes from the Latin for "pea-shaped bone".

Function

The primary function of the os pisiforme is to provide a smooth surface for the tendon of the flexor carpi ulnaris muscle to glide over. This allows the muscle to flex the wrist smoothly and efficiently. The os pisiforme also serves as a support for the ulnar artery, which supplies blood to the hand.

Clinical Significance

Injury to the os pisiforme is relatively rare, but can occur as a result of trauma to the wrist, such as a fall onto an outstretched hand. Symptoms of an os pisiforme injury can include pain and swelling in the wrist, particularly on the ulnar side. Treatment typically involves rest, immobilization of the wrist, and in some cases, surgery.