Flexor carpi ulnaris muscle Flexor carpi ulnaris muscle The flexor carpi ulnaris muscle (or FCU) is a muscle of the human forearm that acts to flex and adduct (medial deviation) the hand. Flexor carpi ulnaris muscle arises by two heads, humeral and ulnar, connected by a tendinous arch beneath which the ulnar nerve and artery pass. Its insertion is into the pisiform bone, into the hamate bone via the pisohamate ligament and into the fifth metacarpal bone via the pisometacarpal ligament. The muscle acts to flex and adduct the wrist joint. The flexor carpi ulnaris muscle is innervated by the ulnar nerve which has
Intercarpal joints the hamate, the other, the pisometacarpal ligament, joins the pisiform to the base of the fifth metacarpal bone. These ligaments are, in reality, prolongations of the tendon of the Flexor carpi ulnaris. These joints are also arthrodial joints connected by dorsal, volar, and interosseous ligaments. The dorsal ligaments are three in number, extend transversely from one bone to another on the dorsal surface, connecting the greater with the lesser multangular, the lesser multangular with the capitate, and the capitate with the hamate. The volar ligaments are also three and have a similar arrangement on the volar surface. The three interosseous