Corpus: Musculocutaneous nerve
from Latin: musculus - mouse, muscle; cutis - skin
Definition
The musculocutaneous nerve is a mixed nerve that arises from the lateral cord of the brachial plexus. It contains fibers from the spinal cord segments C5 to C7.
Course
The nerve initially follows the lower edge of the pectoralis minor muscle, then pierces the coracobrachialis muscle and runs obliquely between the biceps brachii muscle and the brachialis muscle from the medial to the lateral side of the upper arm. On its way, it sends fibers to the two muscles, some of which continue to the joint capsule of the elbow joint. Above the elbow, lateral to the biceps tendon, it pierces the superficial cord and radiates into the subcutaneous tissue of the forearm as the lateral antebrachial cutaneous nerve. There it passes the cephalic vein at the level of the cubital fossa and divides into a volar and a dorsal branch.
Function
The musculocutaneous nerve innervates the following muscles of the upper arm:
As a variation, the branch to the coracobrachialis muscle can also originate directly, i.e., separately, from the lateral cord of the brachial plexus. The nerve innervates the joint capsule of the elbow joint and the dorsal and volar skin areas on the radial side of the forearm.