Posterior branch of medial antebrachial cutaneous nerve

The posterior branch of medial antebrachial cutaneous nerve (a.k.a. posterior branch of medial cutaneous nerve of forearm) originates from the antebrachial cutaneous nerve just above the medial epicondyle of humerus. The posterior branch gives of 10 to 12 secondary branches which provide cutaneous innervation to the extensor or posterior aspect of the skin of the medial surface of the forearm, all the way down to the wrist region.

Please note that the medial antebrachial cutaneous nerve comes off from the medial cord of brachial plexus. It has cell bodies situated in C8 and T1 spinal segments. The nerve initially descends in the arm but then penetrates the deep fascia of the arm along with the basilic vein, proximal to medial epicondyle of humerus. It is here that the medial antebrachial cutaneous nerve divides into anterior and posterior branches.