Nerves of the Upper Limb

Question 1

What are the ventral rami that make up the brachial plexus?

Answer 1

C5,6,7,8 and T1

Question 2

What is a prefixed brachial plexus?

Answer 2

A plexus from C4-8

Question 3

What is a postfixed brachial plexus?

Answer 3

A plexus from C5-T2

Question 4

What are the divisions of the brachial plexus?

Answer 4

roots, trunks, divisions, cords, branches

Question 5

Which roots make up the upper trunk?

Answer 5

C5 and C6

Question 6

Which roots make up the middle trunk?

Answer 6

C7

Question 7

Which roots make up the lower trunk?

Answer 7

C8 and T1

Question 8

What does each trunk divide into?

Answer 8

an anterior and posterior divisions

Question 9

What do the anterior divisions supply?

Answer 9

flexor muscles and the skin overlying them

Question 10

What do the posterior divisions supply?

Answer 10

extensor muscles and the skin overlying them

Question 11

How are the cords named?

Answer 11

based on their relationship to the axillary artery - lateral, medial and posterior

Question 12

What makes up the lateral cord?

Answer 12

anterior divisions of upper and middle trunks

Question 13

What makes up the medial cord?

Answer 13

anterior division of the lower trunk

Question 14

What makes up the posterior cord?

Answer 14

all of the posterior divisions

Question 15

What makes up the musculocutaneous branch?

Answer 15

the lateral cord

Question 16

What makes up the median nerve?

Answer 16

the lateral cord and the medial cord

Question 17

What makes up the ulnar nerve?

Answer 17

the medial cord

Question 18

What makes up the axillary nerve?

Answer 18

the posterior cord

Question 19

What makes up the radial nerve?

Answer 19

the posterior cord

Question 20

Where do the medial cutaneous nerves of arm and forearm branch off?

Answer 20

from the medial cord

Question 21

Which parts of the brachial plexus are above the clavicle?

Answer 21

roots and trunks

Question 22

Which parts of the brachial plexus are behind the clavicle?

Answer 22

divisions

Question 23

Which parts of the brachial plexus are below the clavicle?

Answer 23

cords and branches

Question 24

Which roots supply the musculocutaneous nerve?

Answer 24

C5,6,7

Question 25

What muscles does the musculocutaneous nerve supply?

Answer 25

coracobrachialis, brachialis, biceps

Question 26

Which muscle does musculocutaneous pierce?

Answer 26

coracobrachialis

Question 27

Where does musculocutaneous descend?

Answer 27

in the arm above brachialis and deep to biceps

Question 28

Where does musculocutaneous become superficial?

Answer 28

lateral to the tendon of biceps at the elbow joint - becomes lateral cutaneous nerve of forearm

Question 29

Are injuries to musculocutaneous common?

Answer 29

no

Question 30

What is the cutaneous supply of musculocutaneous?

Answer 30

lateral side of the forearm

Question 31

Which roots supply the ulnar nerve?

Answer 31

C8 and T1 (with contribution from C7)

Question 32

Where does the ulnar nerve descend in the arm?

Answer 32

medial to the artery

Question 33

What injury at the elbow risks injury to the ulnar nerve?

Answer 33

fracture of the medial epicondyle

Question 34

Where does the ulnar nerve descend in the forearm?

Answer 34

underneath FCU on top of the medial part of FDP

Question 35

How does the ulnar nerve cross the wrist?

Answer 35

superficial to the flexor retinaculum - at risk in a laceration to the wrist

Question 36

Which carpal bone does the ulnar nerve tuck in next to?

Answer 36

pisiform

Question 37

What is the motor supply of the ulnar nerve?

Answer 37

FCU, medial half of FDP, and all of the muscles in the hand except the thenar eminence and half the lumbricals

Question 38

What is the cutaneous supply of the ulnar nerve?

Answer 38

medial 1 and a half fingers and related dorsal and palmar aspect of the hand

Question 39

What roots supply the median nerve?

Answer 39

C5,6,7,8,T1

Question 40

How does the median nerve descend in the arm?

Answer 40

starts off anterior or lateral to the artery and as it descends it becomes medial to the artery

Question 41

Where is the median nerve in the elbow?

Answer 41

medial to the artery

Question 42

How does the median nerve descend in the forearm?

Answer 42

goes through the fibrous arch of FDS and then passes in the middle of the forearm between the superficial and deep muscles

Question 43

How does the median nerve cross the wrist?

Answer 43

in the flexor retinaculum through the carpal tunnel - at risk in carpal tunnel syndrome

Question 44

What is the motor supply of the median nerve?

Answer 44

all of the anterior muscles of the forearm except FCU and half of FDP and in the hand it supplies the thenar eminence and the lateral 2 lumbricals

Question 45

What branch of the median nerve supplies the thenar eminence?

Answer 45

the recurrent thenar branch

Question 46

What is the cutaneous supply of the median nerve?

Answer 46

lateral 3 and a half fingers and their associated palmar region at at least the nail beds of the lateral 3 and a half fingers for the dorsal aspect

Question 47

Why isn’t the cutaneous supply affected in carpal tunnel syndrome?

Answer 47

because cutaneous branches are given off before it enters the carpal tunnel

Question 48

What nerve roots supply the axillary nerve?

Answer 48

C5 and 6

Question 49

Where does the axillary nerve enter the posterior compartment of the arm?

Answer 49

between teres major and teres minor

Question 50

When is the axillary nerve at risk?

Answer 50

in a shoulder dislocation

Question 51

What is the motor supply of the axillary nerve?

Answer 51

deltoid and teres minor

Question 52

What is the cutaneous supply of the axillary nerve?

Answer 52

the military badge area

Question 53

What nerve roots supply the radial nerve?

Answer 53

C5,6,7,8 and T1

Question 54

Where does the radial nerve enter the posterior compartment of the arm?

Answer 54

beneath teres major

Question 55

What is the path of the radial nerve in the arm?

Answer 55

spiral around the shaft of the humerus from medial to lateral

Question 56

When is the radial nerve at risk?

Answer 56

in a fracture of the shaft of the humerus or a poorly fitted crutch

Question 57

Where does the radial nerve travel in the forearm?

Answer 57

Divides into the posterior interosseus nerve (deep branch) and the superficial branch - the deep branch travels through supinator and then in the middle of the posterior compartment of the forearm and the superficial branch travels under brachioradialis - the deep branch supplies the muscles and the superficial branch is cutaneous

Question 58

Where does the radial nerve cross the hand?

Answer 58

in the roof of the anatomical snuffbox on to the dorsum of the hand

Question 59

What is the motor supply of the radial nerve?

Answer 59

all extensor muscles in the arm and forearm

Question 60

Why doesn’t a fracture to the shaft of the humerus effect the action of the triceps?

Answer 60

because the branches to supply the triceps branch off just at the radial nerve emerges - well before it get to the humerus

Question 61

What is the cutaneous supply of the radial nerve?

Answer 61

the posterior aspect of the arm, forearm and part of the dorsum of the hand - variable area but will always include the first webbed space

Question 62

What is the cutaneous supply of the medial side of the arm?

Answer 62

the medial cutaneous nerve of arm and forearm

Question 63

When do you see a dermatomal and myotomal deficit?

Answer 63

If the nerve damage is at the root not the nerve branches

Question 64

What is the dermatomal supply of the middle finger?

Answer 64

C7