Brachialis m

The brachioradialis m. is the longest of the forearm mm.  It is the most lateral (radial) of the forearm flexors, and is the only flexor compartment m. that is innervated by the radial n.  (radial n. innervates extensors of the arm and forearm).  It originates on the humerus and inserts into the styloid process of the radial bone, so it has no action at the wrist, but is an elbow flexor.