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:

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.

Origin

Lateral supracondylar ridge of the humerus

Insertion

Lateral aspect of the distal radius, at the base of the radial styloid process

Innervation

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.

Blood Supply
  • Radial recurrent artery (from the radial artery just below the elbow)
Action
  • Flexion: the brachioradialis lies anterior to the elbow joint, and therefore causes flexion of the forearm. It is a weak flexor compared to the biceps brachii and brachialis – look how distal the insertion is. Its action to flex is strongest when the forearm is midway between pronation and supinatino
  • Pronation and supination