The main portion of the median nerve supplies these muscles:
Superficial group:

Pronator teres
Flexor carpi radialis
Palmaris longusIntermediate group:

Flexor digitorum superficialis muscleThe anterior interosseus branch of the median nerve supplies these muscles:
Deep group:

Flexor digitorum profundus (only the lateral half)
Flexor pollicis longus
Pronator quadratus

Hand
In the hand, the median nerve supplies motor innervation to the first and second lumbrical muscles. It also supplies the muscles of the thenar eminence by a recurrent thenar branch. The rest of the intrinsic muscles of the hand are supplied by the ulnar nerve. The median nerve innervates the skin of the palmar (volar) side of the index finger, thumb, middle finger, and half the ring finger, and the nail bed. The radial aspect of the palm is supplied by the palmar cutaneous branch of the median nerve, which leaves the nerve proximal to the wrist creases. This palmar cutaneous branch travels in a separate fascial groove adjacent to the flexor carpi radialis and then superficial to the flexor retinaculum. It is, therefore, spared in carpal tunnel syndrome. Clinical significance
Injury
Injury of median nerve at different levels causes different syndromes with varying motor and sensory deficits. At the shoulder
Injury can occur at the brachial plexusAbove the elbow

Common mechanism of injury: A supracondylar humerus fracture
Motor deficit:
Loss of pronation of forearm, weakness in flexion of the hand at the wrist, loss of flexion of radial half of digits and thumb, loss of abduction and opposition of thumb.
Forearm
The median nerve continues in the cubital fossa medial to the brachial artery and passes between the two heads of  the pronator teres, deep to the bicipital aponeurosis (aponeurosis of biceps) and superficial the brachialis muscle. It crosses the ulnar artery (branch of brachial artery) while being separated by the deep head of the pronator teres. It then travels between the flexor digitorum superficialis (above) and flexor digitorum profundus (below). The median nerve is accompanied by the median artery (a branch of anterior interosseous artery) during this course. Then,  about 5 cm above the flexor retinaculum (wrist), it emerges between the flexor digitorum superficialis (medially) and the flexor carpi radialis (laterally) into the hand.The main trunk of the median nerve innervates the superficial and deep groups of the muscles in the anterior compartment of the forearm with the exception of flexor carpi ulnaris. The median nerve does this by giving off two branches as it courses through the forearm:

Muscular branches are given off in the cubital fossa to supply flexor carpi radialis, palmaris longus, and flexor digitorum superficialis. The anterior interosseous branch is given off in the upper part of the forearm, courses with the anterior interosseous artery and innervates flexor pollicis longus and the lateral half of flexor digitorum profundus (the ulnar half is supplied by ulnar nerve, as is the flexor carpi ulnaris muscle). It ends with its innervation of pronator quadratus.