Brachial Plexus

Question 1

What are the divisions of the brachial plexus

Answer 1

Roots
Trunks
Divisions
Cords
Branches
Read That Damn Cadaver Book

Question 2

What forms the roots of the brachial plexus

Answer 2

Anterior divisions of spinal nerves C5-T1

Question 3

What do the posterior divisions of C5-T1 do

Answer 3

Innervate skin and musculature of trunk

Question 4

Where do the roots of the brachial plexus pass

Answer 4

Between anterior and medial scalene muscles to enter base of neck

Question 5

What are the three trunks of the brachial plexus

Answer 5

Superior trunk
Middle trunk
Inferior trunk

Question 6

Where do the roots of the brachial plexus converge and form trunks

Answer 6

Base of the neck

Question 7

What forms the superior trunk of the brachial plexus

Answer 7

Combination of C5 and C6 roots

Question 8

What forms the middle trunk of the brachial plexus

Answer 8

Continuation of C7 root

Question 9

What forms the inferior trunk of the brachial plexus

Answer 9

Combination of C8 and T1 roots

Question 10

Where do the trunks of the brachial plexus move once formed

Answer 10

Laterally, crossing posterior triangle of the neck

Question 11

What happens to the brachial plexus in the posterior triangle of the neck

Answer 11

Each trunk divides into two branches - anterior and posterior divisions

Question 12

Where do the divisions of the brachial plexus then pass

Answer 12

Leave the posterior triangle and pass into the axilla

Question 13

When do the divisions of the brachial plexus recombine to form cords

Answer 13

Once they have entered the axilla

Question 14

What are the cords of the brachial plexus

Answer 14

Lateral cord
Posterior cord
Medial cord

Question 15

What forms the lateral cord of the brachial plexus

Answer 15

Anterior division of superior trunk

Anterior division of middle trunk

Question 16

What forms the posterior cord of the brachial plexus

Answer 16

Posterior division of superior trunk
Posterior division of middle trunk
Posterior division of inferior trunk

Question 17

What forms the medial cord of the brachial plexus

Answer 17

Anterior division of the inferior trunk

Question 18

Where do the cords give rise to the branches of the brachial plexus

Answer 18

In the axilla and proximal aspect of the upper limb

Question 19

What are the branches of the brachial plexus

Answer 19

Musculocutaneous
Axillary
Median
Radial 
Ulnar

Question 20

What roots form musculocutaneous nerve

Answer 20

C5, C6, C7

Question 21

What are the motor functions of musculocutaneous nerve

Answer 21

Innervates brachialis, biceps brachii and coracobrachialis

Question 22

What are the sensory functions of the musculocutaneous nerve

Answer 22

Gives off lateral cutaneous branch of the forearm:-
Innervates lateral half of anterior forearm
Innervates small lateral portion of posterior forearm

Question 23

What roots make up the axillary nerve

Answer 23

C5 and C6

Question 24

What are the motor functions of the axillary nerve

Answer 24

Innervates teres minor and deltoid muscles

Question 25

What are the sensory functions of the axillary nerve

Answer 25

Gives off superior lateral cutaneous nerve of the arm:- | Innervates inferior region of deltoid

Question 26

What are the roots of the median nerve

Answer 26

C6-T1

Question 27

What are the motor functions of the median nerve

Answer 27

Flexor muscles of the forearm Thenar muscles Two lateral lumbricals

Question 28

What are the sensory functions of the median nerve

Answer 28

Gives off palmar cutaneous branch - innervates lateral part of palm Gives off digital cutaneous branch - innervates lateral three and a half fingers on palmar surface of hand

Question 29

What are the roots of the radial nerve

Answer 29

C5-8 and T1

Question 30

What are the motor functions of the radial nerve

Answer 30

Triceps brachii | Extensor muscle in the posterior compartment of the forearm

Question 31

What are the sensory functions of the radial nerve

Answer 31

Posterior aspect of arm and forearm | Posterior, lateral aspect of hand

Question 32

What are the roots of the ulnar nerve

Answer 32

C8 and T1

Question 33

What are the motor functions of the ulnar nerve

Answer 33

Muscles of the hand (except thenar muscles and lateral two lumbricals) Flexor carpi ulnaris Medial half of flexor digitorum profundus

Question 34

What are the sensory functions of the ulnar nerve

Answer 34

Anterior and posterior surfaces of medial one and a half fingers Associated palm area

Question 35

What minor branches arise from the roots of the brachial plexus

Answer 35

Dorsal scapular nerve | Long thoracic nerve

Question 36

What minor branches arise from the trunks of the brachial plexus

Answer 36

Suprascapular nerve | Nerve to subclavius

Question 37

What minor branches arise from the lateral cord of the brachial plexus

Answer 37

Lateral pectoral nerve

Question 38

What minor branches arise from the medial cord of the brachial plexus

Answer 38

Medial pectoral nerve Medial cutaneous nerve of arm Medial cutaneous nerve of forearm

Question 39

What minor branches arise from the posterior cord of the brachial plexus

Answer 39

Superior subscapular nerve Thoracodorsal nerve Inferior subscapular nerve

Question 40

What nerves are affected in an Erb's palsy

Answer 40

``` Nerves from C5 and C6 roots: Musculocutaneous nerve Axillary nerve Suprascapular nerve Nerve to subclavius ```

Question 41

What muscles are paralysed in Erb's palsy

Answer 41

``` Supraspinatus Infraspinatus Subclavius Biceps brachii Brachialis Coracobrachialis Deltoid Teres minor ```

Question 42

Which movements are lost/greatly weakened

Answer 42

Abduction at shoulder Exteral rotation of arm Supination of forearm Flexion at shoulder

Question 43

Where is the sensation loss in Erb's palsy

Answer 43

Down lateral side of arm

Question 44

What mechanism of injury causes Klumpke palsy

Answer 44

Excessive abduction of the arm

Question 45

What nerves are affected in Klumpke palsy

Answer 45

Nerves from T1 root: Ulna nerve Median nerve

Question 46

What muscles are paralysed in Klumpke palsy

Answer 46

All small muscles of the hand | MCPJs hyperextended and IPJs are flexed giving clawed appearance

Question 47

What sensory loss is associated with Klumpke palsy

Answer 47

Loss of sensation along medial side of arm