From the Research
The radial nerve originates from the posterior cord of the brachial plexus (C5-T1) and follows a complex course through the upper limb, making it vulnerable to injury at several points, particularly in the spiral groove during humeral fractures, against the lateral epicondyle, and within the supinator muscle. The course of the radial nerve can be described as follows:
- It begins in the axilla and travels posteriorly, passing through the triangular space between the long head of triceps, teres major, and humerus to enter the posterior compartment of the arm.
- The nerve then courses obliquely in the spiral groove of the humerus, where it is closely associated with the deep brachial artery.
- After supplying the triceps muscle, the radial nerve pierces the lateral intermuscular septum to enter the anterior compartment of the arm near the lateral epicondyle.
- At the level of the elbow, it divides into superficial and deep branches.
- The superficial branch continues distally along the lateral forearm, deep to the brachioradialis muscle, and eventually emerges between the brachioradialis and extensor carpi radialis longus tendons to supply sensation to the dorsolateral hand.
- The deep branch (posterior interosseous nerve) pierces the supinator muscle via the arcade of Frohse, winds around the radius, and supplies the extensor muscles of the forearm. This anatomical course is supported by various studies, including 1, which compared outcomes of tendon transfers versus nerve transfers for the management of isolated radial nerve injuries, and 2, which discussed the treatment of radial nerve palsy. The radial nerve's complex course and vulnerability to injury highlight the importance of proper management and treatment of radial nerve injuries, as discussed in studies such as 3 and 4.