Median

Question 1

What roots is the median nerve derived from?

Answer 1

C5-T1

Question 2

What is the origin of this nerve?

Answer 2

Lateral and medial cords

Question 3

Describe the course of the median nerve

Answer 3

Runs with brachial artery
Passes through the medial part of the antecubital fossa between the two heads of pronator teres muscle
Travels through the anterior forearm between the flexor digitorum superficialis and flexor digitorum profundus muscles and gives three main branches:
1) Anterior interosseous nerve – descends along anterior interosseous membrane

2) deep branch – enters hand through the carpal tunnel beneath flexor retinaculum of wrist, between flexor carpi radialis and flexor digitorum superficialis tendons
3) superficial/palmar cutaneous branch – arises just before the wrist and pierces the palmar carpal ligament to enter the palm over the top of the carpal tunnel

Question 4

What is the sensory supply of this nerve?

Answer 4

Skin over the thenar eminence
Lateral 2/3 palm of hands
Palmar aspect lateral 3 1/2 fingers
Dorsal fingertips of lateral 3 1/2 fingers

Question 5

What is the motor supply of this nerve?

Answer 5

All muscles of anterior compartment of forearm except flexor carpi ulnaris and the medial two parts of flexor digitorum profundus

a) pronator teres and pronator quadratus – pronate forearm
b) flexor carpi radialis – flexes and abducts wrist
c) palmaris longus – flexes wrist and tenses palmar aponeurosis
d) flexor digitorum superficialis – flexes fingers at PIPJs
e) lateral two parts of flexor digitorum profundus – flex index and middle fingers at DIPJs
f) flexor pollicis longus – flexes thumb at IPJ

LOAF muscles

a) lateral two lumbricals – flex MCPJs and extend IPJs of index and middle finger
b) opponens pollicis – opposes thumb
c) abductor pollicis brevis – abducts thumb
d) flexor pollicis brevis – flexes thumb at MCPJ

Question 6

How could this nerve get injured?

Answer 6

Compression by carpal tunnel
Deep wrist wounds (self harm)
Supracondylar fracture humerus

Question 7

What are the features of injuring this nerve?

Answer 7

Hand of Benediction: Can’t flex middle or index fingers
Numbness over thenar eminence and median sensory distribution
paralysis of most of anterior compartment of forearm – weak forearm pronation, wrist flexion and abduction, and weak finger flexion with preservation of DIPJ flexion at ring and little fingers