Ligaments are typically bands of fibrous tissue that connect one bone to another. The pisohamate ligament is part of the structure of the hand, where it connects the pisiform bone to the hook of the hamate. The pisiform is found where the inner bone of the forearm (the ulna) and the wrist (carpus) meet. The hamate is located at the base of the fourth and fifth metacarpal bones and is distinguished by a hook-like projection. The pisohamate is an extension of the flexor carpi ulnaris tendon and part of the origin for the abductor digiti minimi muscle, along with the pisiform bone and the flexor retinaculum. It arises from the pisiform and inserts on the hamate. Between the pisiform and the hook of the hamate is a depression known as the tunnel of Guyon. The pisohamate ligament forms the roof of that canal. Because the tunnel of Guyon encloses the ulnar nerve and artery, it is a common location for compression injuries of the wrist.