The deep branch of the ulnar nerve is a terminal, primarily motor branch of the

ulnar nerve The ulnar nerve is a nerve that runs near the ulna, one of the two long bones in the forearm. The ulnar collateral ligament of elbow joint is in relation with the ulnar nerve. The nerve is the largest in the human body unprotected by muscle or ...

. It is accompanied by the deep palmar branch of ulnar artery.

Structure

It passes between the abductor digiti minimi and the flexor digiti minimi brevis. It then perforates the

opponens digiti minimi The opponens digiti minimi (opponens digiti quinti in older texts) is a muscle in the hand. It is of a triangular form, and placed immediately beneath the palmaris brevis, abductor digiti minimi and flexor digiti minimi brevis. It is one of the ...

and follows the course of the

deep palmar arch The deep palmar arch (deep volar arch) is an arterial network found in the palm. It is usually primarily formed from the terminal part of the radial artery. The ulnar artery also contributes through an anastomosis. This is in contrast to the super ...

beneath the flexor tendons. As the deep ulnar nerve passes across the palm, it lies in a fibrous tunnel formed between the hook of the

hamate The hamate bone (from Latin language, Latin wiktionary:hamatus, hamatus, "hooked"), or unciform bone (from Latin language, Latin ''wikt:uncus, uncus'', "hook"), Latin os hamatum and occasionally abbreviated as just hamatum, is a bone in the huma ...

and the

pisiform The pisiform bone ( or ), also spelled pisiforme (from the Latin ''pisiformis'', pea-shaped), is a small knobbly, sesamoid bone that is found in the wrist. It forms the ulnar border of the carpal tunnel. Structure The pisiform is a sesamoid bone, ...

( Guyon's canal).

Function

At its origin it innervates the hypothenar muscles. As it crosses the deep part of the hand, it innervates all the interosseous muscles and the third and fourth lumbricals. It ends by innervating the

adductor pollicis In human anatomy, the adductor pollicis muscle is a muscle in the hand that functions to Adduction, adduct the thumb. It has two heads: transverse and oblique. It is a fleshy, flat, triangular, and fan-shaped muscle deep in the Thenar eminence, ...

and the medial (deep) head of the

flexor pollicis brevis The flexor pollicis brevis is a muscle in the hand that flexes the thumb. It is one of three thenar muscles. It has both a superficial part and a deep part. Origin and insertion The muscle's superficial head arises from the distal edge of the ...

. It also sends articular filaments to the wrist-joint (following Hilton's law)

References

External links

* {{Authority control Nerves of the upper limb