What is the origin and course of the median nerve?

The median nerve originates from spinal nerve roots C5–T1 via the lateral and medial cords of the brachial plexus. It travels from the axilla down the arm, crossing the brachial artery, then passes through the cubital fossa, between the heads of the pronator teres muscle in the forearm, and finally through the carpal tunnel at the wrist to enter the hand.

What muscles does the median nerve innervate?

The median nerve supplies several key muscles, including forearm flexors like flexor carpi radialis and flexor digitorum superficialis, thenar muscles in the hand such as abductor pollicis brevis, and the first and second lumbricals.

What are the sensory functions of the median nerve?

The median nerve provides sensation to the skin of the lateral palm and the palmar and dorsal aspects of the lateral 3½ digits (thumb, index, middle, and half of the ring finger), essential for fine tactile discrimination.

What is carpal tunnel syndrome and how does it affect the median nerve?

Carpal tunnel syndrome is a condition where the median nerve is compressed within the carpal tunnel at the wrist, causing symptoms like burning pain and numbness in the lateral 3½ digits and possible thenar muscle weakness.

What are the clinical signs of a median nerve injury at the elbow?

An injury at the elbow can cause loss of pronation, weak wrist flexion, a benediction deformity (inability to flex index and middle fingers), and sensory loss over the lateral palm and 3½ digits.

How does a median nerve injury at the wrist differ from one at the elbow?

A wrist injury primarily affects the thenar muscles and sensory distribution, while an elbow injury also impairs forearm flexors and pronation, causing more extensive motor deficits.

What is the anterior interosseous nerve and what does it supply?

The anterior interosseous nerve is a branch of the median nerve that supplies motor innervation to the flexor pollicis longus, lateral half of flexor digitorum profundus, and pronator quadratus muscles.

Median Nerve Anatomy – Course & Carpal Tunnel

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