ulnar nerve

Last reviewed 01/2018

The ulnar nerve is derived from the medial cord of the brachial plexus and carries fibres from the 8th cervical nerve and 1st thoracic nerve

  • C8 and T1 nerve roots give rise to the medial cord which in turn, forms the ulnar nerve

The ulnar nerve does not give off any branches above the elbow. In the upper arm, it is closely related to the brachial artery and the median nerve. It passes behind the medial epicondyle of the humerus into the forearm. In the hand, close to the hamate bone, it divides into deep and superficial branches.

It is both motor and sensory:

  • motor - in the forearm, to flexor carpi ulnaris and the inner half of flexor digitorum profundus; in the hand to, palmaris brevis, the hypothenar eminence, the two inner lumbricals, the palmar and dorsal interossei, the oblique and transverse heads of adductor pollicis, and the inner head of flexor pollicis brevus. The first dorsal interosseous may be supplied by the median nerve.

  • sensory - palmar and dorsal aspects of ulnar one and a half fingers.