Brachial Plexus

Question 1

What are the spinal nerves which make up the cervical plexus?

Answer 1

C1-4

Question 2

What are the spinal nerves which make up the brachial plexus?

Answer 2

C5-8 and T1

Question 3

How do the spinal nerves in the brachial Plexus subdivide?

Answer 3

From roots - trunks - divisions - cords - branches

Question 4

Describe the formation of roots in the brachial plexus

Answer 4

C5+6 combine
C7 stays alone
C8+t1 combine

Question 5

Describe formation of trunks from roots

Answer 5

C5+6 create superior trunk
C7 creates middle trunk
C8+t1 create inferior trunk

Question 6

Describe formation of trunks to divisions

Answer 6

Superior, Middle and inferior trunk all subdivide into posterior and anterior divisions (6 divisions in total: superior posterior, superior anterior, Middle posterior etc etc

Question 7

Describe the formation of divisions to cords

Answer 7

Superior and middle anterior combine to make the lateral cord

Superior, inferior and middle posterior divisions combine to make the posterior cord

Inferior anterior division makes the medial cord

Question 8

Describe the formation of branches from cords

Answer 8

Lateral cord forms into subcutaneous nerve

Posterior cord forms into Axillary nerve

Medial and lateral cord form into Median nerve

Posterior cord forms into radial nerve

Medial cord forms into ulnar nerve

Question 9

What muscles does the Axillary nerve innervate?

Answer 9

Deltoid
Teres Minor
Long head of triceps

Question 10

What movement does axillary nerve initiate?

Answer 10

Shoulder flexion and abduction to 90 degrees

Question 11

What pathology can be caused by injury to the axillary nerve?

Answer 11

Flat shoulder which is atrophy of deltoid and teres minor, often caused by fracture to neck of humerus

Question 12

What are the origins of the radial nerve?

Answer 12

C5-T1

Question 13

What area does the radial nerve provide sensory supply to

Answer 13

Posterior of arm all the way up to thr posterior of hand

Question 14

What muscles are innervation by the radial nerve

Answer 14

Triceps, brachioradialis, anconeous, extensor carpi radialis longus and brevis

Question 15

What movements is the radial nerve responsible for

Answer 15

Mostly elbow and wrist extension

Question 16

Name a pathology caused by damage to the radial nerve

Answer 16

Saturday night palsy, cause by compression, also wrist drop, inability to extend wrist - often caused by fracture to midspan shaft of humerus

Question 17

What are the roots of the musculosubcutaneous nerve?

Answer 17

C5-7

Question 18

What muscles are innervation by musculusubcutaneous nerve

Answer 18

Biceps, brachialis, coracobrachialis

Question 19

What part of the arm does it innervate?

Answer 19

Anterior up to lateral aspect of forearm

Question 20

What movements does musculosubcutaneous nerve allow for

Answer 20

Elbow flexion and assists in supination and shoulder flexion

Question 21

If the subcutaneous nerve is damaged, what will the signs be

Answer 21

Inability to flex elbow

Question 22

What are the roots of the median nerve

Answer 22

C5-8 and t1

Question 23

What muscles does the median nerve innervate

Answer 23

Pronator teres, flexor carpi radialis, palnus longus, flexor digiitorum superficiality and flexor digitorum profundity, flexor pollicis longus all thenar muscles and lateral 2 lumbricals

Question 24

What movements does the median nerve allow

Answer 24

Pronation, wrist flexion, flexion of digits 1-3

Question 25

What are the signs if someone has an injury to the median nerve?

Answer 25

Unable to pronate, weak wrist flexion and inability to flex thumb - ape hand due to atrophy of the arm muscles meaning thumb opposition isn’t possible and also the hand of benediction where digits 1-3 are extended and 4-5 are flexed

Question 26

What are the roots of the ulnar nerve

Answer 26

C8 and t1

Question 27

What muscles are innervation by ulnar nerve

Answer 27

Flexor carpi ulnaris
Flex digitorum profundis (fingers 4-5)
Adductor pollicis
Hypothenar muscles
Lumbricals 4_5

Question 28

What movements are made possible by ulnar nerve

Answer 28

Wrist flexion
Thumb adduction
Flexion of digits 4_5

Question 29

What will be the signs of an injury to the ulnar nerve

Answer 29

Partial claw hand. - hyperextension of MCP in digits 4 and 5 and flexion of IP in digits 4 and 5
Weak wrist flexion

Question 30

What does the mnemonic DR. Cuma stand for?

Answer 30

Drop Radial, Claw Ulnar, Median Ape