Arising from the upper two-thirds of the lateral supracondylar ridge, the muscle passes along the preaxial border of the forearm to a tendon that is inserted at the base of the styloid process of the radius. The muscle forms the lateral border of the cubital fossa; passing down the forearm it overlies the radial nerve and the radial artery as they lie together on supinator, pronator teres tendon, flexor digitorum superficialis and flexor pollicis longus. The lower part of the tendon is covered by abductor pollicis longus and extensor pollicis brevis as they spiral down to the thumb.
Nerve supply of brachioradialis:
By the radial nerve (C5, 6) above the elbow joint (before the posterior interosseous nerve is given off).
Action of brachioradialis:
Its action is to flex the elbow joint. It pulls on the radial styloid process, which is thus made the leading point as the forearm flexes; the ulnar side of the forearm passively follows, falling into the position of mid-pronation.