Median Nerve Flashcards
Describe the nerve roots of median Nerve
C5 - T1
Describe the course of the median nerve in the arm
Median Nerve originates from medial and lateral cord of the brachial plexus (C6-T1), it exits the axilla inferior to teres major. It travels down the anterior compartment of the arm lateral to the brachial artery. It then enters the ACF.
Describe the course of the median nerve in the forearm.
After entering ACF exits through the two head of pronator teres, before travelling down in the plane between FDS to FDP before entering the carpal tunnel. It gives of two major branches in the forearm, Anterior Interosseous nerve and Palmar cutaneous nerve.
Describe the course of the median nerve in the hand and the branches it gives off.
After entering the carpal tunnel it gives off the recurrent branch and the subsequent digital branches.
What does the median nerve innervate?
Median nerve innervates the superficial and intermediate comparments of the arm.
FCR, PT, PL, FDS.
What does the AIN Innervate?
AIN innervates the deep comparment of the anterior forearm including pronator quadratus, radial half of FDP and Flexor pollicus Longus. OK Sign to test.
What does the recurrent branch innervate?
Thenar muscles (OAF) - Opponens Pollicus, Abductor Pollicis brevis, Flexor pollicis brevis
Whats a quick way to identify median nerve injury.
Check sensation of thenar eminence, volar aspect pulp of index finger. Check thumb abduction (abductor pollicis brevis) and AIN.
How would you test higher or lower lesion?
Test LOAF muscles and AIN.
Palmar Cutanous branch given off before carpal tunnel. Sensation still in tact of thenar eminance.
OK Sign - FDP and FPL used. High elbow or forearm laceration.
High lesion, hand flexion may be weak and associated with addiction from FCU
Low lesion: wrist flexion will be unaffected, may have weakness flexing the 2nd and 3rd digit. Thumb abduction - OAF muscles
I would test the AIN and LOAF muscles of the hand, also assesing for wrist flexion.
