Nerve supply of the upper limbs

Question 1

What are the 5 subdivions of the brachial plexus?

Answer 1

Roots
Trunk
Divisions
Cords
Branches

(read that damn cadaver book)

Question 2

What are the roots of the brachial plexus?

Answer 2

C5,6,7,8 and T1-Anterior rami

Question 3

What are the trunks of the brachial plexus?

Answer 3

Superior trunk-C5 and C6
Middle trunk-continuation of C7
Inferior trunk- combination of the C8 and T1 roots

Question 4

What are the divisions of the brachial plexus?

Answer 4

Each of the trunks of the trunks of the brachial plexus split into an anterior and posterior branch

Question 5

What are the cords of the brachial plexus?

Answer 5

Lateral cord- anterior division of superior trunk and anterior division of middle trunk
Posterior cord- posterior division of superior trunk, posterior division of middle trunk, posterior division of the inferior trunk
Medial cord- anterior division of the inferior trunk

Question 6

What are the branches of the brachial plexus?

Answer 6

Musculocutanous nerve
Axillary nerve
Median nerve
Radial nerve
Ulnar nerve

Question 7

How are these branches related to the cords of the brachial plexus

Answer 7

Musculocutanous- Lateral
Axillary-Posterior
Radial-posterior 
Median- Lateral and medial
Ulnar- medial

Question 8

Summarise the Roots, trunks, divisions, cords and branches of the brachial plexus

Answer 8

google images

Question 9

What is Erb’s palsy

What movements are affected?

Answer 9

Commonly occurs due to an excessive increase in the angle between the neck and shoulder which stretches or tears the C5 and C6 roots.

“Waiters tip” palsy- weak flexion of the wrist, loss of shoulder abduction, lateral rotation of the arm, supination of forearm and shoulder flexion

Question 10

What are the spinal roots of the axillary nerve?

What are the sensory functions of it?

What are its motor functions?

Answer 10

C5 and C6

Gives rise to upper lateral cutaneous nerve of arm which innervates the skin over the lower deltoid (badge area)

Innervates deltoid and teres minor

Question 11

Describe the anatomical course of the axillary nerve?

Answer 11

Passes anterior to the subscapularis muscle and exits via the quadrangular space. Terminates in the shoudler where it splits into three branches

Question 12

What are the nerve roots of the musculocutanous nerve?

What are its sensory functions?

What are its motor functions?

Answer 12

C5-C7

Gives rise to the lateral cutaneous nerve of the forearm, which innervates the lateral aspect of the forearm

Muscles in the anterior compartment of the arm

Question 13

What is the musculocutanous nerve’s anatomical course

Answer 13

Leaves the axilla and pierces the coracobrachialis near the top of thhe muscle. It then runs straight down the middle of the anterior compartment and terminates at the elbow

Question 14

What are the nerve roots of the median nerve?

What are its sensory functions?

What are its motor functions?

Answer 14

C6-T1

Lateral aspect of palm, lateral three fingers on palmar surface. tips of thumb, index, middle and ring finger of dorsal surface

anterior forearm compartment and thenar muscles

Question 15

Describe the anatomical course of the median nerve?

Answer 15

Travels down the lateral aspect of the arm, lateral to the brachial artery. Moving central through the cubital fossa at the elbow and then travelling down to the thumb.Wh

Question 16

What common neuropathy involves compression of the median nerve

Answer 16

Carpal tunnel syndrome

Question 17

What are the nerve roots of the radial nerve?

What are its sensory innervations?

What are its motor innervations?

Answer 17

C5-T1

Innervates skin on posterior forearm, dorsal surface of the palm, dorsal surface of lateral three and half digits

triceps brachii and extensor muscles in forearm

Question 18

Describe the anatomical course of the radial artery

Answer 18

Travels in the posterior arm supplying the triceps and then travelling in the radial groove where it wraps around the humerus. It is accompanied by the deep branch of the brachial artery. Travels through cubital fossa and travels down posterior forearm

Question 19

What occurs if the radial nerve is damaged in the axilla e.g. by a humeral fracture

Answer 19

loss of innervation to triceps and posterior forearm leading to a wrist drop

Question 20

What are the roots of the ulnar nerve

What are its sensory functions?

What are its motor functions?

Answer 20

C8-T1

anterior and posterior surfaces of medial one and half areas

Innervates the intrinsic muscles of the hand apart from the thenar muscles and the two lateral lumbricals and the two muscles in the forearm:flexor carpi ulnaris and flexor digitorum profundus

Question 21

Describe the anatomical course of the ulnar nerve

Answer 21

Travels medially down the arm on the anterior aspect of the arm

Question 22

How do you test for ulnar nerve palsy?

Answer 22

Ask patient to grip paper between forefinger and thumb and then pull they should be able to hold onto it.