Transverse carpal ligament

Flexor retinaculum of the hand
The mucous sheaths of the tendons on the front of the wrist and digits. (Transverse carpal ligament labeled at center.)
Details
Identifiers
Latin	retinaculum musculorum flexorum manus (obsolete: ligamentum transversum carpi)
TA	A04.6.03.013
Anatomical terminology []

The flexor retinaculum (transverse carpal ligament, or anterior annular ligament) is a fibrous band on the palmar side of the hand near the wrist. It arches over the carpal bones of the hands, covering them and forming the carpal tunnel.

The flexor retinaculum is a strong, fibrous band that covers the carpal bones on the palmar side of the hand near the wrist. It attaches to the bones near the radius and ulna. On the ulnar side, the flexor retinaculum attaches to the pisiform bone and the hook of the hamate bone. On the radial side, it attaches to the tubercle of the scaphoid bone, and to the medial part of the palmar surface and the ridge of the trapezium bone.

The flexor retinaculum is continuous with the palmar carpal ligament, and deeper with the palmar aponeurosis. The ulnar artery and ulnar nerve, and the cutaneous branches of the median and ulnar nerves, pass on top of the flexor retinaculum. On the radial side of the retinaculum is the tendon of the flexor carpi radialis, which lies in the groove on the greater multangular between the attachments of the ligament to the bone.

The tendons of the palmaris longus and flexor carpi ulnaris are partly attached to the surface of the retinaculum; below, the short muscles of the thumb and little finger originate from the flexor retinaculum.

The flexor retinaculum is the roof of the carpal tunnel, through which the median nerve and tendons of muscles which flex the hand pass.