Brachial Plexus

Question 1

What are the 5 parts of the brachial plexus?

Answer 1

Roots, Trunks, Division, Cords and branches

remember: Read That Damn Cadaver Book

Question 2

What forms the roots of the brachial plexus?

Answer 2

The spinal nerves C5, C6, C7, C8, T1

Question 3

How do the spinal nerves leave the spinal cord?

Answer 3

Intervertebral foramina of the vertebral column

Question 4

Each nerve divides into an anterior and posterior fibre, the roots of the brachial plexus are formed by which of these divisions?

Answer 4

Anterior division of spinal nerves C5-T1

Question 5

After their formation the nerves at the roots of the brachial plexus pass between what to enter the base of the neck?

Answer 5

Anterior and medial scalene

Question 6

At the base of the neck , the roots of the brachial plexus converge to form trunks,h ow many trunks are there and what are they called?

Answer 6

3
Superior
Middle
Lateral

Question 7

Which nerves does the superior trunk of the brachial plexus consist of?

Answer 7

C5 and C6

Question 8

Which nerves does the middle trunk of the brachial plexus consist of?

Answer 8

C7

Question 9

Which nerves does the inferior trunk of the brachial plexus consist of?

Answer 9

C8 and T1

Question 10

Within the posterior triangle of the neck, each trunk of the brachial plexus divides into branches. How many branches does each trunk divide into and which way do they travel? What are the branches called?

Answer 10

Each trunk divides into 2 branches
Travelling anterior and posteriorly
The branches are therefore called the anterior and posterior division

this is the division section of the brachial plexus

Question 11

What route do the 3 anterior and 3 posterior divisions take in the brachial plexus?

Answer 11

Leave the posterior triangle of the neck and pass into the axilla region

they will recombine in the next part of the brachial plexus

Question 12

What are the names given to the 3 nerves that are formed by the recombination of the divisions in the brachial plexus?

Answer 12

Lateral
Posterior
Medial

so name because of their position relative to the axillary artery

Question 13

What is the lateral cord of the brachial plexus formed by?

Answer 13

Anterior division of the superior trunk

Anterior division of the middle trunk

Question 14

What is the posterior cord of the brachial plexus formed by?

Answer 14

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

Question 15

What is the medial cord of the brachial plexus formed by?

Answer 15

Anterior division of the inferior trunk

Question 16

What do the cord of the brachial plexus give rise to?

Answer 16

The major branches

Question 17

What are the roots of the musculocutaneous nerve?

Answer 17

C5, C6, C7

Remember: 3 musketeers assassinated 5 mice, 5 rats and 2 unicorns

Question 18

What are the motor functions of the musculocutaneous nerve?

Answer 18

Brachialis, bicep brachii, coracobrachialis

remember:BBC

Question 19

What are the sensory functions of the musculocutaneous nerve?

Answer 19

Gives off the lateral cutaneous branch of the forearm, which innervates the lateral half of the anterior forearm and a small lateral portion of the posterior forearm

Question 20

What are the roots of the axillary nerve?

Answer 20

C5 and C6

Remember: 3 musketeers assassinated 5 mice, 5 rats and 2 unicorns

Question 21

What are the motor functions of the axillary nerve?

Answer 21

Innervates the teres minor and the deltoid muscles

Question 22

What are the sensory functions of the axillary nerve?

Answer 22

Gives off the superior lateral cutaneous nerve of arm, which innervates the inferior region of the deltoid (regimental badge area)

Question 23

What are the roots of the median nerve?

Answer 23

All (C5-T1)

Remember: 3 musketeers assassinated 5 mice, 5 rats and 2 unicorns

Question 24

What are the motor functions of the median nerve?

Answer 24

Innervates most of the flexor muscles in the forearm, the thenar muscles and the two lateral lumbricals that move the index and middle fingers

Question 25

What are the sensory functions of the median nerve?

Answer 25

Gives off the palmar cutaneous branch which innervates the lateral part of the palm and the digital cutaneous branch, which innervates the lateral three and a half fingers on the anterior (palmar) surface of the hand

Question 26

What are the roots of the radial nerve?

Answer 26

C5-8 and T1 **Remember: 3 musketeers assassinated 5 mice, 5 rats and 2 unicorns**

Question 27

What are the motor functions of the radial nerve?

Answer 27

Innervates the tricep brachii and the extensor muscles in the posterior compartment of the forearm

Question 28

What are the sensory functions of the radial nerve?

Answer 28

Innervates the posterior aspect of the arm and forearm, and the posterior, lateral aspect of the hand

Question 29

What are the roots of the ulnar nerve?

Answer 29

C8 and T1 **Remember: 3 musketeers assassinated 5 mice, 5 rats and 2 unicorns**

Question 30

What are the motor functions of the ulnar nerve?

Answer 30

Innervates the muscle of the hand (apart from the thenar muscle and two lateral lumbricals), flexor carpi ulnaris and medial half of flexor digitorum profundus

Question 31

What are the sensory functions of the ulnar nerve?

Answer 31

Innervates the anterior and posterior surfaces of the medial one and half fingers and associated palm area

Question 32

When looking at the brachial plexus, find the structure that is an 'M' shape, what nerves have you found here?

Answer 32

The musculocutaneous, median and ulnar nerves They will be arranged around the brachial artery (Can use this M to get your bearings and work back to find the roots etc)

Question 33

There are also many minor branches of the brachial plexus, name the minor branches off the roots

Answer 33

Doral scapular nerve | Long thoracic nerve

Question 34

There are also many minor branches of the brachial plexus, name the branches off the trunks

Answer 34

Suprascapular nerve | Nerve to subclavian

Question 35

There are also many minor branches of the brachial plexus, name the branches off the medial cord

Answer 35

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

Question 36

There are also many minor branches of the brachial plexus, name the branches off the lateral cord

Answer 36

Lateral pectoral nerve

Question 37

There are also many minor branches of the brachial plexus, name the branches off the posterior cord

Answer 37

Superior subscapular nerve Thoracodorsal nerve Inferior subscapular nerve

Question 38

What does an upper brachial plexus injury affect?

Answer 38

The superior roots

Question 39

What does a lower brachial plexus injury affect?

Answer 39

The inferior roots

Question 40

What does upper brachial plexus injury cause?

Answer 40

Erb's palsy

Question 41

What causes Erb's palsy?

Answer 41

When there is excessive increase in the angle between the neck and shoulder- stretches or even tears the nerve roots

Question 42

What nerves are affected by Erb's palsy?

Answer 42

Nerves derived from solely C5 or C6 roots: | Musculocutaneous, axillary, suprascapular and nerve to subclavius

Question 43

What muscles become paralysed as a result of Erb's palsy?

Answer 43

Supraspinatus, subclavius, bicep brachii, brachialis, coracobrachialis, deltoid and teres minor

Question 44

What motor functions are lost of greatly weakened by Erb's palsy?

Answer 44

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

Question 45

What sensory functions are lost when someone has Erb's palsy?

Answer 45

Loss of sensation down lateral side of arm, which covers the sensory innervation of the axillary and musculocutaneous nerves

Question 46

Why would an arm affected by Erb's palsy hand limply and medically rotated?

Answer 46

Limp due to paralyse | Medially rotated because of unopposed action of pectoralis major

Question 47

What position if characteristic of Erb's palsy?

Answer 47

The waiters' tip

Question 48

What is an injury to the lower brachial plexus called?

Answer 48

Klumpke palsy

Question 49

When down klumpke palsy occur?

Answer 49

When there is excessive abduction of the arm (eg Person catching a branch as they fall from a tree)

Question 50

What nerves are affected by klumpke palsy?

Answer 50

Those derived form T1 Radial Median and ulnar

Question 51

What muscles are paralysed when someone has klumpke palsy?

Answer 51

All the small muscles of the heads (the flexor muscles in the forearm are supplied by the ulna and median nerve but are innervated by different roots)

Question 52

What happens to someone sensory function when they have klumpke pulsy?

Answer 52

They get loss of sensation along media side of arm

Question 53

What is a characteristic of klumpke palsy and why?

Answer 53

A clawed hand | Due to the hyperextended metacarpophalangeal joints and the flexed interphalangeal joints

Question 54

Which group of muscles does the median nerve innervate the majority of?

Answer 54

Anterior forearm