Posterior Branch of Medial Antebrachial Cutaneous Nerve

Origin

The medial antebrachial cutaneous nerve arises from the medial cord of brachial plexus and divides into anterior and posterior terminal branches (C8—T1 spinal segments).

Course

The medial antebrachial cutaneous nerve is a large nerve that arises from the medial cord of the brachial plexus. It descends in the anterior compartment of the arm along with the ulnar nerve and medial to the axillary and brachial artery. The nerve then pierces the deep fascia at approximately the mid-arm, alongside the basilic vein to enter the subcutaneous tissues of the forearm. The medial antebrachial cutaneous nerve divides into anterior and posterior (or volar and ulnar) terminal branches.

The posterior branch (ulnar branch) passes obliquely down along the medial side of the basilic vein to the posterior aspect of the forearm and descends on its ulnar side giving off small cutaneous terminal branches along its course.

Branches

The posterior branch communicates with the medial brachial cutaneous nerve and the posterior antebrachial cutaneous nerve, a branch of the radial nerve.

Supplied Structures

The posterior branch of the medial antebrachial cutaneous nerve provides cutaneous sensory innervation to the skin of the medial portion of the proximal two thirds of the dorsal side of the forearm.