• Clinical science

Median nerve neuropathy


The median nerve is a peripheral nerve originating in the cervical roots C5–T1 of the brachial plexus. It supplies motor innervation to the anterior forearm flexors, the thenar muscles, and the two lateral lumbricals as well as sensory innervation to the lateral palm and anterior, lateral three and a half fingers. Motor and sensory deficits depend on whether the lesion is proximal (above the elbow) or distal (below the elbow). While proximal lesions present with the “hand of benediction,” distal lesions present with either the “pinch sign” (anterior interosseous nerve syndrome) or, in the case of carpal tunnel syndrome, with mildly impaired thumb and index finger motion. Both proximal lesions and carpal tunnel syndrome result in reduced sensation in the area of the thumb, index and middle finger. Anterior interosseus nerve syndrome does not cause any sensory deficits. Chronic injuries to the nerve result in atrophy of median nerve innervated muscles while acute injuries do not have this feature. Treatment is mostly conservative and focuses on rest and immobilization.



Clinical features

Anatomical principles

The median nerve runs from the axilla to the elbow, in the medial side of the arm in the medial bicipital groove. It enters the forearm through the two heads of the pronator teres muscle. After branching off into a motor nerve (anterior interosseous nerve), it courses distally between the superficial and deep layers of the forearm's flexor compartment to reach the wrist, where it branches off into a sensory nerve (the palmar cutaneous branch of the median nerve) before entering the hand through the carpal tunnel.

Location Motor deficit Sensory deficit
Proximal (above elbow)
  • Thumb
  • Index and middle finger
  • Radial side of ring finger
Distal (below elbow)
  • none
Distal (within wrist)
  • Thumb
  • Index and middle finger
  • Radial side of ring finger

A high/proximal lesion of the median nerve manifests in the hand of benediction, while a low/distal lesion does not!






  • 1. Rezaee A, Soltany Hosn S. Pronator Teres Syndrome. https://radiopaedia.org/articles/pronator-teres-syndrome-2. Updated June 13, 2017. Accessed June 13, 2017.
  • 2. Amirlak B, Gellman H. Median Nerve Entrapment. In: Median Nerve Entrapment. New York, NY: WebMD. http://emedicine.medscape.com/article/1242387. Updated February 24, 2016. Accessed August 16, 2017.
  • 3. Andreoli TE, Carpenter CCJ. Cecil Essentials of Medicine. Elsevier; 2010.
  • 4. Joshi J, Kotwal PP. Essentials of Orthopaedics & Applied Physiotherapy - E-Book. Elsevier Health Sciences; 2016.
last updated 06/29/2020
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