ABSTRACT
The medial antebrachial cutaneous nerve originates directly from the medial cord (ulnar fascicle, C8, T1 fibers). It runs distally behind the axilary artery, then in front and medial to the neurovascular bundle of the arm. The medial antebrachial cutaneous nerve pierces the fascia together with the basilic vein in the middle of the brachium. It lies subcutaneously on the ulnar side next to the biceps brachii muscle before running distally to branch into an anterior and ulnar ramus in the region of medial cubital crease. This branch point may lie proximal to the crease. The nerve gives one or two branches to the skin of the brachium. The anterior ramus innervates the skin of the antebrachium nearly to the midline. The ulnar ramus innervates the skin on the posterior side of the forearm to the midline (Figure 16.1). The innervation of the medial antebrachial cutaneous nerve also reaches the brachial region and as far distally as the palmar side of the hand.
