Median nerve

Innervation

• Motor 
  • superficial volar forearm group
    • Pronator teres
    • Flexor carpi radialis
    • Palmaris longus
  • intermediate group
    • Flexor digitorum superficialis
  • deep group
    • Flexor digitorum profundus (lateral)
    • Flexor pollicis longus
    • Pronator quadratus
  • hand
    • 1st and 2nd lumbricals
    • Opponens pollicis
    • Abductor pollicis brevis
• Flexor pollicis brevis

Origin

• Brachial plexus  
  • C5-T1 roots
• medial and lateral cords

Course

• Anterior compartment of arm
  • anterior compartment (anteromedial to humerus)
  • runs with brachial artery (lateral in upper arm / medial at elbow)
  • no branches in the arm
• Forearm
  • enters the forearm between the pronator teres and biceps tendon
  • travels between flexor digitorum superficialis (FDS) and flexor digitorum profundus (FDP)
  • then emerges between the FDS and flexor pollicis longus (FPL)
• Hand
  • the nerve then enters the hand via the carpal tunnel, along with the tendons of the FDS, FDP and FPL
• Terminal branches
  • anterior interosseous branch (AIN)
    • innervates the deep volar compartment of forearm except the ulnar half of the FDP
  • palmar cutaneous branch 
    • supplies sensory innervation to lateral palm
  • recurrent branch (to thenar compartment)
  • digital cutaneous branches
    • supply the radial 3 1/2 digits (palmar)
• can also supply the index, long, and ring fingers dorsally

Clinical Conditions

•  Carpal tunnel syndrome  
•  AIN neuropathy 
•  Pronator syndrome