A patient loses the ability to flex his forefinger. The nerve that supplies the muscles that cause this action is formed from which of the following cord(s) of the brachial plexus?
The muscles involved are the flexor digitorum superficialis and the flexor digitorum profundus. The flexor digitorum superficialis is completely supplied by the median nerve. The flexor digitorum profundus is supplied by both the ulnar (little finger side) and median (thumb side) nerves. Flexion of the forefinger is consequently dependent on the median nerve, which is formed by pa of both the medial and lateral cords of the brachial plexus.The lateral cord alone supplies the musculocutaneous nerve. The medial cord alone supplies the ulnar nerve.No nerve is supplied by both the medial and posterior cords . Ref: Moon D.A., Foreman K.B., Albeine K.H. (2011). Chapter 33. Hand. In D.A. Moon, K.B. Foreman, K.H. Albeine (Eds), The Big Picture: Gross Anatomy.
Lateral only
Medial and lateral
Medial only
Medial and posterior