Quick Facts
Origin: Terminal branch of ulnar nerve below the flexor retinaculum.
Course: Passes deep through the hypothenar muscles and curves laterally to end at the adductor pollicis muscle.
Branches: Muscular and articular branches.
Supply: Hypothenar muscles, medial two lumbricals, and interosseous muscles, adductor pollicis muscle, radiocarpal joint.
Origin
The deep branch of ulnar nerve arises below the flexor retinaculum as one of the terminal branches of ulnar nerve in the palmar aspect of the hand.
Course
At the radiocarpal joint (wrist), the ulnar nerve lies between the flexor carpi ulnaris and the flexor digitorum superficialis muscles. The nerve enters the palm by passing superficial to the flexor retinaculum and lateral to pisiform bone, while being covered by a superficial slip of the retinaculum (volar carpal ligament). At the distal border of retinaculum, the nerve terminates by dividing into its superficial and deep branches.
The deep branch accompanies the deep branch of the ulnar artery. It passes backwards between the abductor and flexor digiti minimi, and then between the opponens digiti minimi and the fifth metacarpal bone, lying on the hook of the hamate. Finally, it turns laterally within the concavity of the deep palmar arch. It ends by supplying the adductor pollicis muscle.
Branches
The deep branch of the ulnar nerve provides muscular branches to the intrinsic muscles of the hand and articular branches to the radiocarpal joint.
Supplied Structures
The deep branch of the ulnar nerve supplies the hypothenar muscles (abductor digiti minimi, flexor digiti minimi, opponens digiti minimi), medial two lumbricals, palmar and dorsal interosseous muscles, adductor pollicis, and deep head of flexor pollicis brevis muscles. It also supplies the radiocarpal joint.
