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
Hamate bone of the hand. The ossification of the hamate starts between 1 and 12 months. The hamate does not fully ossify until about the 15th year of life. The bone is also found in many other mammals, and is homologous with the "fourth distal carpal" of reptiles and amphibians. The carpal bones function as a unit to provide a bony superstructure for the hand. The hamate bone is the bone most commonly fractured when a golfer hits the ground hard with a golf club on the downswing or a hockey player hits the ice with a slap shot. The fracture is