Origin It is the smallest and medial-most branch of the
brachial plexus, and arising from the
medial cord receives its fibers from the eighth cervical and first thoracic spinal nerves.
Course It passes through the
axilla, at first lying behind, and then medial to the
axillary vein, and communicates with the
intercostobrachial nerve. It descends along the medial side of the
brachial artery to the middle of the arm, where it pierces the
deep fascia, and is distributed to the skin of the back of the lower third of the
arm, extending as far as the
elbow, where some filaments are lost in the skin in front of the medial epicondyle, and others over the
olecranon. It communicates with the ulnar branch of the
medial antebrachial cutaneous nerve. ==Eponym==