The brachioradialis is one of the muscles of the superficial layer of the posterior compartment of the forearm. This muscles forms the bulk which makes up the anterolateral aspect of the forearm when the palms are facing forward in the anatomical position.
The posterior compartment of the forearm consists of a superficial layer (7 muscles) and a deep layer (5 muscles).
The muscles of the superficial layer include:
- Extensor carpi radialis longus
- Extensor carpi radialis brevis
- Extensor digitorum
- Extensor digiti minimi
- Extensor carpi ulnaris
The muscles of the superficial layer share a common origin from the lateral epicondyle and lateral supracondylar ridge of the humerus.
All the muscles of the posterior compartment are innervated by the radial nerve.
Lateral supracondylar ridge of the humerus
Lateral aspect of the distal radius, at the base of the radial styloid process
The radial nerve emerges from the posterior compartment of the arm just deep to the brachioradialis. The brachioradialis muscle covers the bifurcation of the radial nerve as it divides into the superficial and deep branches.