A biomedical engineer would like to reconstruct the arm of a boy who underwent amputation to treat a life-threatening infection. In designing the prosthetic arm, the engineer will need to know that which of the following muscles flexes the elbow and is innervated by the radial nerve?

Brachioradialis
Flexor digitorium longus
Brachialis
Extensor digitorium longus
Biceps brachii

Brachialis, biceps brachii, and the brachioradialis are the three main flexor group of muscles that help in bending the elbow. For bending the arm these muscles decrease the angle between upper arm and forearm. Out of these three muscles Brachioradialis only gets the radial nerve supply by the radial muscular branches.

Other muscle groups that help in flexing elbow are triceps brachii. Medial muscle branches of radial nerve supply to the medial head of triceps brachii.