Muscular Branch of Radial Nerve to Medial Head of Triceps Brachii (Right)

Origin

A motor nerve branch to the medial head of triceps brachii muscle originates from the radial nerve and contains motor nerve fibers from the C6—C8 cervical spinal segments.

Course

The radial nerve comes off from the posterior cord in the lower part of the axilla. Here it runs behind the third part of axillary artery while lying against the muscles of the posterior wall of the axilla, i.e., subscapularis, teres major, and latissimus dorsi muscles.

In the upper part of the arm, it descends posterolaterally (with the profunda brachii vessels) through the lower triangular space, between the shaft of the humerus, long head of triceps brachii, and teres major muscles. The nerve then enters the radial groove along with the profunda brachii vessels. It descends downwards and laterally between the lateral and medial heads of the triceps muscle, while in contact with the humerus.

The radial nerve innervates the medial head of triceps brachii both proximally and distally. The most proximal of the two branches to the medial head arises from the radial nerve before it enters the radial groove while the second distal one arises as the nerve descends inside the radial groove. The later descends further to innervate the anconeus muscle.

Branches

There are no named branches.

Supplied Structures

The muscular branch of the radial nerve to medial head of triceps provides motor innervation to the medial head of triceps muscle. The radial nerve gives off several branches to innervate all three heads of the triceps brachii muscle.