Antebrachial cutaneous nerves
There are three cutaneous nerves that provide a sensory supply for the skin of the forearm. These three nerves are the medial antebrachial cutaneous nerve, lateral antebrachial cutaneous nerve and the posterior antebrachial cutaneous nerve.
The medial antebrachial cutaneous nerve arises from the brachial plexus and supplies the skin of the medial portion of the forearm. The lateral antebrachial cutaneous nerve arises from the musculocutaneous nerve and supplies sensory innervation to the radial aspect of the forearm. The posterior antebrachial cutaneous nerve arises from the radial nerve and supplies the skin overlying the posterior forearm.
This article will discuss the anatomy and function of the antebrachial cutaneous nerves.
|Medial antebrachial cutaneous nerve
Origin: Medial cord of the brachial plexus (C8-T1)
Supply: Skin overlying medial forearm and olecranon
|Lateral antebrachial cutaneous nerve
Origin: Musculocutaneous nerve
Supply: Skin overlying the lateral (radial) aspect of the forearm
|Posterior antebrachial cutaneous nerve
Origin: Radial nerve
Supply: Skin of the posterior forearm
- Medial antebrachial cutaneous nerve
- Lateral antebrachial cutaneous nerve
- Posterior antebrachial cutaneous nerve
Medial antebrachial cutaneous nerve
The medial antebrachial cutaneous nerve, also known as the medial cutaneous nerve of the forearm, arises from the medial cord of the brachial plexus (root value C8-T1). Upon originating, the nerve courses through the anterior arm between the axillary artery and axillary vein, along with the medial pectoral nerve and ulnar nerve. The medial cutaneous nerve then pierces the deep fascia of the arm and terminates around the medial epicondyle where it gives two terminal branches.
The terminal branches of the medial cutaneous nerve of the forearm are the anterior branch and the posterior branch. The anterior branch is the larger branch that descends in the anteromedial aspect of the forearm, coursing anterior to the median cubital vein. The smaller, posterior branch, is typically located in the proximo-medial region of the posterior forearm. In addition, the antebrachial cutaneous nerve also gives off a small cutaneous branch in the arm that supplies the skin overlying the biceps brachii muscle.
To summarize, the medial cutaneous nerve of the forearm is a sensory nerve that provides sensation for the skin overlying the biceps brachii, elbow, ulnar aspect of the anterior and posterior forearm.
Lateral antebrachial cutaneous nerve
The lateral antebrachial cutaneous nerve, also referred to as the lateral cutaneous nerve of the forearm, is a continuation of the musculocutaneous nerve. After the musculocutaneous nerve gives off its muscular branches to the biceps brachii and brachialis muscles, it continues as the lateral antebrachial cutaneous nerve. This nerve starts its course by passing alongside the lateral margin of the biceps brachii tendon and deep to the cephalic vein. It then continues to descend down the radial aspect of the forearm as far as the wrist. At the wrist, the lateral cutaneous nerve is located anterior to the radial artery. It terminates around the base of the thenar eminence, where it gives off several cutaneous branches.
The nerve provides several branches. These branches include:
- The recurrent branch follows the course of the cephalic vein and provides sensation to the skin overlying the distal third of the arm.
- The communicating branches connect with the posterior cutaneous nerve of the forearm and the radial nerve (via its terminal branch).
The lateral cutaneous nerve of the forearm is solely a sensory nerve. Its main function is to innervate the skin of the anterior half and radial posterior quarter of the forearm.
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Posterior antebrachial cutaneous nerve
The posterior antebrachial cutaneous nerve, also known as the posterior cutaneous nerve of the forearm, originates from the radial nerve, proximal to the elbow. The nerve then perforates the triceps brachii muscle and descends down the arm and forearm, all the way to the wrist.
The main function of this nerve is to supply sensation to the posterior aspect of the forearm.
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