Ulnar n

One of the 5 terminal branches of the brachial plexus, the ulnar n. passes posterior to the medial epicondyle of the humerus, where it is very superficial and subject to injury.  It supplies motor innervation in the forearm to the flexor carpi ulnaris and the medial half of the flexor digitorum profundus.  In the hand it supplies motor innervation to the hypothenar eminence, the 3rd and 4th lumbricals, and all of the Interosseus mm.  It has a sensory territory on the medial part of the hand.