GLOSSARY

The ulnar nerve is a branch of the medial cord of the brachial plexus (roots C8–T1) that passes behind the medial epicondyle of the elbow (the area known as the “funny bone”) and enters the hand through Guyon’s canal; it supplies most of the small muscles of the hand and is essential for fine finger movements and grip strength.

Functions

• Motor (forearm): flexor carpi ulnaris and the medial half of flexor digitorum profundus (the ring and little fingers).
• Motor (hand): the interosseous muscles (spreading and closing the fingers), the third and fourth lumbricals, the hypothenar muscles, and adductor pollicis.
• Sensory: the little finger, the medial half of the ring finger, and the inner edge of the hand.

Clinical Application