Median Nerve

Question 1

Nerve roots

Answer 1

C5-T1

Question 2

Motor function

Answer 2

Innervates the flexors in the anterior compartment of the forearm (except flexor carpi ulnaris and part of flexor digitorum profundus
Also supplies thenar muscles and lateral 2 lumbricals
In general these muscles perform pronation of forearm, flexion of wrist and flexion of the digits

Question 3

Sensory function

Answer 3

Gives rise to the palmar cutaneous branch which innervates the lateral part of the palm
Gives rise to the digital cutaneous branch which innervates the lateral 3 and a half fingers on the palmar surface of the hand

Question 4

Major branches

Answer 4

Anterior interosseous nerve

Palmar digital cutaneous nerve

Question 5

Carpal Tunnel Syndrome

Answer 5

Can be caused by thickened ligaments/tendon sheaths
Tests - Tinel’s sign = tapping the median nerve to elicit pain
Tests - Phalen’s manoeuvre = holding the wrist in flexion for 60 seconds to elicit pain

Question 6

Damage at the elbow

Answer 6

Supracondylar fracture of the humerus
Forearm constantly supinated and flexion is weak
Flexion at the thumb is also prevented (longus and braves paralysed)
Lack of sensation over lateral palm and lateral 3 and a half digits of the palmar surface
Thenar eminence wasted, only ring and little fingers can flex completely (hand of benediction when trying to make a fist)

Question 7

Damage at wrist

Answer 7

Laceration proximal to the flexor retinaculum
Thenar muscles and lateral two lumbricals paralysed
Affects opposition of thumb and flexion of index and middle fingers
Affects sensory and motor functions of median nerve