12 - Nerve palsies in limbs

Question 1

define dermatome?

Answer 1

sensory area of skin supplied by a single spinal nerve

Question 2

what results in axial lines?

Answer 2

embryological development of limb buds growing out from body wall

Question 3

is there overlap between dermatomes?

Answer 3

adjacent dermatomes = yes, adjacent pre/post- axial dermatomes = no

Question 4

why are lower limb dermatomes distorted?

Answer 4

rotation and extension, and borrowing of the skin from trunk

Question 5

rhyme for remembering S1-S4?

Answer 5

stand on S1, sleep on S2, sit on S3 and shit on S4

Question 6

define Hilton’s Law?

Answer 6

The nerves crossing a joint supply the muscles acting on it and the joint itself

Question 7

which 3 nerves supply the hip joint?

Answer 7

obturator nerve (predominately), femoral nerve, lateral femoral cutaneous nerve

Question 8

define myotome?

Answer 8

group of muscles supplied by one segment of spinal cord

Question 9

what is the brachial plexus?

Answer 9

large network of nerves supplying the upper limb, extending from the cervical spine to the axilla

Question 10

name 5 divisions of the brachial plexus?

Answer 10

roots, trunks, divisions, cords, branches

Question 11

where would damage to C5, 6 affect?

Answer 11

deltoid and shoulder muscles, brachialis and biceps

Question 12

what palsy causes porter’s tip position?

Answer 12

Erb’s palsy

Question 13

describe the actions of the shoulder, elbow, forearm and wrist in porter’s tip?

Answer 13

shoulder adduction, elbow extension, forearm pronation, wrist flexion

Question 14

what does klumpke’s paralysis look like?

Answer 14

clawed hand

Question 15

when is the axillary nerve at risk of damage?

Answer 15

surgical neck of humerus

Question 16

what motor deficit is associated with axillary n damage?

Answer 16

loss of shoulder (deltoid) abduction

Question 17

what sensory deficit is associated with axillary n damage?

Answer 17

badge area

Question 18

what are the 5 nerve roots of the radial n?

Answer 18

C5, 6, 7, 8, T1

Question 19

which artery is the radial n closely associated?

Answer 19

profunda brachii artery

Question 20

between which 2 muscles does the radial nerve enter the forearm?

Answer 20

brachioradialis and brachialis

Question 21

which nerves are at risk in saturday night palsy?

Answer 21

axillary and radial nerves

Question 22

when is the radial n at risk?

Answer 22

spiral groove of humerus and lateral intermuscular septum

Question 23

what motor deficit is associated with radial n damage?

Answer 23

wrist drop

Question 24

what sensory deficit is associated with radial n damage?

Answer 24

1st web space dorsally

Question 25

3 nerve roots of the median nerve?

Answer 25

C7, 8, T1

Question 26

which artery is the median n closely associated?

Answer 26

brachial a

Question 27

where does the median n enter the forearm?

Answer 27

by passing between the 2 heads of the pronator teres

Question 28

what is at risk with damage to the median n?

Answer 28

volar aspect of the wrist (and cubital fossa)

Question 29

name 2 complications associated with damage to the median n?

Answer 29

carpal tunnel syndrome, wrist lacerations

Question 30

what motor deficit is associated with median n damage?

Answer 30

monkey hand (thenar wasting), pointing finger

Question 31

what sensory deficit is associated with median n damage?

Answer 31

volar aspect thumb

Question 32

3 nerve roots of the ulnar nerve?

Answer 32

C7, 8, T1

Question 33

which arteries is the ulnar n closely associated?

Answer 33

superior collateral a and ulnar a

Question 34

where does the ulnar n enter the forearm?

Answer 34

passing between the 2 heads of the flexor carpi ulnaris

Question 35

where is at risk with damage to the ulnar n?

Answer 35

behind the medial epicondyle of humerus, wrist and canal of guyon

Question 36

what motor deficit is associated with ulnar n damage?

Answer 36

claw hand, hypothenar and 1st dorsal interosseous wasting

Question 37

what sensory deficit is associated with ulnar n damage?

Answer 37

little finger

Question 38

where is the lumbar plexus located?

Answer 38

lies on surface of quadratus lumborum and within body of psoas muscle

Question 39

where do most major nerves of the hip exit the pelvis?

Answer 39

the sciatic foramen

Question 40

which nerves of the hip do not exit the pelvis via the sciatic foramen?

Answer 40

genitofemoral & ilioinguinal, femoral, lateral femoral cutaneous and obturator nerves

Question 41

3 nerve roots of the femoral n?

Answer 41

L2-4

Question 42

what is the largest branch of the lumbar plexus?

Answer 42

femoral nerve

Question 43

how does the femoral n leave the pelvis?

Answer 43

passes through the psoas muscle and exits pelvis under the inguinal ligament, lateral to femoral triangle

Question 44

what is in the femoral triangle?

Answer 44

femoral a, v, and lymphatic channels

Question 45

what does the femoral n supply?

Answer 45

quadriceps muscles in anterior thigh

Question 46

where does the femoral v terminate?

Answer 46

in long fine sensory branch

Question 47

2 nerve roots of the lateral femoral cutaneous nerve?

Answer 47

L2,3

Question 48

where does the lateral femoral cutaneous nerve lie?

Answer 48

lies on surface of iliacus muscle

Question 49

how does the lateral femoral cutaneous nerve exit the pelvis?

Answer 49

under lateral end of inguinal ligament

Question 50

what is the function of the lateral femoral cutaneous nerve?

Answer 50

purely sensory to lateral aspect thigh

Question 51

what causes meralgia paraesthetica?

Answer 51

compression of the lateral femoral cutaneous nerve

Question 52

nerve roots of the sciatic n?

Answer 52

L4-S3

Question 53

what is the largest nerve in the body?

Answer 53

sciatic n

Question 54

what is the main branch of the sacral plexus?

Answer 54

sciatic n

Question 55

how does the sciatic n exit the pelvis?

Answer 55

through sciatic foramen below piriformis muscle

Question 56

to which muscle does the sciatic nerve run deep?

Answer 56

gluteus maximus

Question 57

which nerve supplies the hamstring muscles?

Answer 57

sciatic n

Question 58

what does the sciatic n supply?

Answer 58

hamstring muscles, part of adductor magnus, and all lower leg and foot muscles via terminal branches

Question 59

3 occasions when the sciatic n is at risk?

Answer 59

posterior dislocation of hip, IM injections, surgery

Question 60

nerve roots of the common fibular nerve?

Answer 60

L4-S2

Question 61

what is the smaller and lateral branch of the sciatic nerve?

Answer 61

common fibular n

Question 62

what does deficit of common fibular nerve cause?

Answer 62

foot drop and slapping gait

Question 63

most commonly injured nerve in lower limb?

Answer 63

common fibular nerve

Question 64

where does the common fibular nerve lie?

Answer 64

passes around the lateral aspect of the neck of the fibula

Question 65

what n is the communicating branch to the sural n?

Answer 65

common fibular n

Question 66

which nerve divides to give rise to the superficial and deep fibular nerves?

Answer 66

common fibular nerve