Presence of an ape hand deformity when the hand is at rest, due to an hyperextension of index finger and thumb, and an adducted thumb
Presence of benediction sign when attempting to form a fist, due to loss of flexion of radial half of digits
Sensory deficit: Loss of sensation in lateral 3+1⁄2 digits including their nail beds, and the thenar areaAt the elbow

Entrapment at the level of the elbow or the proximal forearm could be due to the pronator teres syndrome.Within the proximal forearm: Anterior interosseous syndrome

Injury to the anterior interosseous branch in the forearm causes the anterior interosseous syndrome
Common mechanisms: Tight cast, forearm bone fracture
Motor deficit: Loss of pronation of forearm, loss of flexion of radial half of digits and thumb
Sensory deficit: NoneAt the wrist

Common mechanism: Wrist laceration
Motor deficit:
Weakness in flexion of radial half of digits and thumb, loss of abduction and opposition of thumb
Presence of an ape hand deformity when the hand is at rest may be likely, due to an hyperextension of index finger and thumb, and an adducted thumb. Nevertheless, an ape hand deformity is not a requirement for a carpal tunnel syndrome diagnosis.
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.