The Musculocutaneous nerve is a terminal branch of the lateral cord of the Brachial Plexus. It emerges at the inferior border of Pectoralis minor muscle.It passes lateral to the axillary and upper part of brachial artery. It leaves the axilla to then pierce the Corocobrachialis near it humeral insertion to lie in the intermuscular septum between biceps brachii and brachialis muscles.Then it enters the elbow by piercing deep fascia and terminates as the Lateral Cutaneous nerve of the forearm.
Ventral rami of C5, C6, C7
- Brachialis ( also has supply from Radial nerve)
- Biceps Brachii(both long head and short head)
- lateral cutaneous nerve to the lateral forearm (both front and back)
- Coracobrachialis - flexes and adducts the glenohumeral (GH) joint and acts to stabilise the humeral head in the glenoid fossa when the arm is hanging freely by side.
- Brachialis- flexion of the elbow joint.
- Biceps Brachii- a weak abductor of GH joint when arm externally rotated, weak flexor of GH joint, helps to stabilise GH joint when weight carried in arm, supinator and flexor of the elbow joint.
- Brachial Plexus damage
- Compression injury eg weight lifting or sports involving lots of forarm flexing and supination.The biceps aponeurosis and tendon compress against the fascia of the brachialis muscle causing sensory loss below the elbow on the lateral side of the forearm.
- Dislocation of the shoulder
- Shoulder surgery
- Entrapment of the nerve at the elbow
Considerable anatomical variations present with this nerve. This may lead to clinical implications in surgery, diagnosis.
- Check sensation on lateral forearm
see the following links
- Chaurasia BD. Human Anatomy.6th ed. Vol1,CBS Publisers and distributors Pvt Ltd.
- Osama Eqeel. Musculocutaneous nerve. Available from: https://www.youtube.com/watch?v=46PTcikRi44 (last accessed 20.3.2019)
- Saladin KS. "The Muscular System." Anatomy & Physiology: The Unity of Form and Function. New York, NY: McGraw-Hill, 2012. 346. Print.
- Kleiber T, Kunz L, Disselhorst-Klug C. Muscular coordination of biceps brachii and brachioradialis in elbow flexion with respect to hand position. Frontiers in physiology. 2015 Aug 6;6:215.
- Patient. Musculocutaneous nerve. Available from: https://patient.info/doctor/musculocutaneous-nerve-lesion-c5-c6 (last accessed 20.3.2019)
- Healthline. Musculocutaneous nerve. Available from: https://www.healthline.com/human-body-maps/musculocutaneous-nerve#1 (last accessed 20.3.2019)