Median Nerve

Question 1

Describe the motor supply of Median nerve?

Answer 1

SUPERFICIAL VOLAR FOREARM

• Pronator Teres
• FCR
• PL

INTERMEDIATE

• FDS

HAND

• 1st/2nd lumbricals
• Opponens pollicis
• Abductor pollicis- thumb to touch pen- feel
• Flexor pollicis brevis

Question 2

What is the origin of median nerve?

Answer 2

• Medial and Lateral cords, C5-T1 roots

Question 3

What is the course of the median nerve?

Answer 3

• Anterior compartment of arm
  
  • anteromedial to humerus
  • runs with brachial artery ( lateral in upper arm/medial at elbow)
  • no branches in arm
• Forearm
  
  • enters between PT and biceps tendon
  • travels between FDS and FDP
  • emerges between FDS and FPL
• ​​Hand
  
  • enters via carpal tunnel along with tendons on FDS/FDP and FPL

Question 4

Describe the terrminal branches of median nerve?

Answer 4

• Anterior interosseous nerve
  
  • innervates the deep volar compartment of forearm except ulnar half of FDP
• Palmar cutaneous branch
  
  • sensory innervation to lateral palm
• Recurrent branch to thenar compartment
• digital cutaneous branches
  
  • supply radial 3 1/2 digits ( palmar)

Question 5

What are the clinical coniditons of median nerve compression?

Answer 5

• Carpal tunnel syndrome
• AIN neuropathy
• Pronator syndrome

Question 6

Describe the motor supply of AIN?

Answer 6

• Pronator quadratus
• Flexus pollicis longus (FPL)
• radial 1/2 of Flexor digitorum profundus (FDP)

Question 7

What is the course of the AIN?

Answer 7

• Arises from the median nerve
• approx 4cm distal to the medial epicondyle where it passes into the anterior interosseous membrane to sires of innervation
• motor innervation only - no sensory

Question 8

Name the places that can cause AIN compression?

Answer 8

• Tendinous edge of deep head of pronator teres
  
  • most common cause
• FDS arcade
• edge of lacertus fibrosis
• accessory head of FPL- Gantzer’s muscle
• thrombosed ulnar radial or ulnar artery