Peripheral Nervous System

Question 1

What are the roots of the cervical plexus?

Answer 1

C1-C5

Question 2

What nerve roots innervate the brachial plexus?

Answer 2

C5-T1

Question 3

What is the mnemonic for remembering the brachial plexus?

Answer 3

Really tired drink coffee black

roots trunks divisions cords branches

Question 4

What muscles does the musculocutaneous nerve innervate?

Answer 4

the anterior arm muscles (biceps brachii, coracobrachialis, and brachialis)

Question 5

Which age group tend to have the most brachial plexus injuries?

Answer 5

Newborns because of the upper extremity being awkwardly stretched in the birth canal.

Damage is caused to Suprascapular nerve, musculocutaneous and axillary nerves.

Question 6

What are the nerve roots of the lumbar plexus?

Answer 6

L1-L4

Question 7

What is the function of the obturator nerve?

Answer 7

sensation to the medial thigh, and motor control of the hip adductor muscles

Question 8

What is the function of the femoral nerve?

Answer 8

Innervates the muscles of the anterior thigh and hip. Also, sensation to the anterior thigh, hip and knee joints.

Question 9

Does compression of a nerve affect touch perception or pain first?

Answer 9

Touch perception

Question 10

Herpes Zoster

Answer 10

Viral infection of sensory ganglia of spinal and cranial nerves

caused by varicella virus

Question 11

Which Lumbar plexus nerves are sensory only?

Answer 11

Genitofemoral (scrotum and labia)

Lateral Femoral Cutaneous(lateral part of thigh)

Saphenous (medial leg and foot; part of knee joint)

Question 12

Which lumbar plexus nerves are motor and sensory?

Answer 12

Iliohypogastric (anterior abdominal wall sensory and motor)

Ilioinguinal (anterior abdominal muscles; groin sensation)

Obturator (L2-L4) (sensation medial thigh; motor to hip adductors)

Femoral

Question 13

What forms the Sacral Plexus?

Answer 13

L4-L5; S1-S4

Question 14

Largest branch in sacral plexus?

Answer 14

Sciatic nerve

also largest nerve in body

Question 15

Sacral plexus divides into what nerves?

Answer 15

tibial nerve (L4-S3)

Common fibular nerve (L4-S2)

Question 16

Superior Gluteal nerve (L4-S1) innervates

Answer 16

hip muscles: gluteus medius, gluteus minimus, tensor fascia lata

Question 17

Inferior gluteal nerve (L5-S2) innervate

Answer 17

gluteus maximus

Question 18

Is posterior cutaneous nerve sensory or motor?

Answer 18

purely sensory to buttocks, posterior thigh and anus

Question 19

Superficial fibular nerve innervates

Answer 19

lateral compartment muscles (fibularis longus and brevis)

Question 20

Deep fibular nerve innervates

Answer 20

anterior compartment (dorsiflexors)

Question 21

Pudendal nerve (inferior branch of sacral plexus) (S2-S4) innervates

Answer 21

perineum and pelvic floor, bladder, sensation to genitals, etc

Question 22

Epineurium is

Answer 22

outermost covering of peripheral nerves.

continuous with dura mater around spinal cord

Question 23

Perineurium is

Answer 23

groups individual nerve fibers into bundles

protects nerves from blood

Question 24

Endoneurium is

Answer 24

innermost connective tissue sheath

Question 25

Axoplasm

Answer 25

fluid inside axons

Question 26

Alpha motor neurons

Answer 26

innervate muscles to create muscle tension and produce movement Fast conducting with a thick myelin sheath

Question 27

Gamma Motor Neurons

Answer 27

innervate muscle spindles to maintain and alter muscle tension Does not cause movement. Slow conducting.

Question 28

Lower motor neurons

Answer 28

neurons that innervate muscles

Question 29

B fibers

Answer 29

small and myelinated

Question 30

C fibers

Answer 30

unmyelinated

Question 31

Diabetic neuropathy sympoms

Answer 31

``` paresthesias paresis hypotension tachycardia digestive problems bowel and bladder incontinence sexual dysfunction thickening of blood vessels leading to ischemia ```

Question 32

Musculocutaneous nerve roots

Answer 32

C5-C7

Question 33

Musculocutaneous motor function

Answer 33

muscles in the anterior compartment of the arm (coracobrachialis, biceps brachii and the brachialis).

Question 34

Musculocutaneous sensory function

Answer 34

gives rise to the lateral cutaneous nerve of forearm, which innervates the lateral aspect of the forearm.

Question 35

Axillary nerve roots

Answer 35

C5 and C6

Question 36

Axillary sensory function

Answer 36

Gives rise to the upper lateral cutaneous nerve of arm, which innervates the skin over the lower deltoid

Question 37

Axillary motor function

Answer 37

Innervates the teres minor and deltoid muscles.

Question 38

Radial nerve roots

Answer 38

C5-T1

Question 39

Radial sensory function

Answer 39

Innervates most of the skin of the posterior forearm, the lateral aspect of the dorsum of the hand, and the dorsal surface of the lateral three and a half digits.

Question 40

Radial motor function

Answer 40

Innervates the triceps brachii and the extensor muscles in the forearm.

Question 41

Median Nerve root

Answer 41

C6-T1

Question 42

Median motor functions

Answer 42

Innervates the flexor and pronator muscles in the anterior compartment of the forearm (except the flexor carpi ulnaris and part of the flexor digitorum profundus, innervated by the ulnar nerve). Also supplies innervation to the thenar muscles and lateral two lumbricals in the hand.

Question 43

Median sensory function

Answer 43

Gives rise to the palmar cutaneous branch, which innervates the lateral aspect 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 44

Ulnar nerve roots

Answer 44

C8-T1

Question 45

Ulnar motor function

Answer 45

Two muscles of the anterior forearm – flexor carpi ulnaris and medial half of flexor digitorum profundus Intrinsic muscles of the hand (apart from the thenar muscles and two lateral lumbricals)

Question 46

Ulnar sensory function

Answer 46

Medial one and half fingers and the associated palm area.

Question 47

What is the most severe form of Brachial plexus?

Answer 47

Avulsion shows flaccid paralysis of upper extremity

Question 48

Femoral nerve root

Answer 48

L2-L4

Question 49

Femoral Motor function

Answer 49

Innervates the anterior thigh muscles that flex the hip joint (pectineus, iliacus, sartorius) and extend the knee (quadriceps femoris: rectus femoris, vastus lateralis, vastus medialis and vastus intermedius),

Question 50

Femoral Sensory function

Answer 50

Supplies cutaneous branches to the anteromedial thigh (anterior cutaneous branches of the femoral nerve) and the medial side of the leg and foot (saphenous nerve).

Question 51

Sciatic nerve root

Answer 51

L4-S3

Question 52

Sciatic motor functin

Answer 52

Innervates the muscles of the posterior thigh (biceps femoris, semimembranosus and semitendinosus) and the hamstring portion of the adductor magnus (remaining portion of which is supplied by the obturator nerve). Indirectly innervates (via its terminal branches) all the muscles of the leg and foot.

Question 53

Sciatic sensory function

Answer 53

No direct sensory functions. Indirectly innervates (via its terminal branches) the skin of the lateral leg, heel, and both the dorsal and plantar surfaces of the foot.

Question 54

Injury to musculocutaneous nerve functions

Answer 54

Flexion at the shoulder and elbow are weakened but can still be performed by the pectoralis major and brachioradialis respectively. Supination of the forearm is weak, but can still be performed by the brachioradialis.

Question 55

Injury to musculocutaneous nerve sensory

Answer 55

loss of sensation over the lateral side of the forearm.

Question 56

Injury to axillary nerve functions

Answer 56

the deltoid and teres minor muscles will be affected, rendering the patient unable to abduct the affected limb.

Question 57

Injury to axillary sensory functions

Answer 57

the upper lateral cutaneous nerve of arm will be affected, resulting in loss of sensation over the inferior deltoid

Question 58

Erbs palsy

Answer 58

a condition resulting from damage to C5-C6 roots of the brachial plexus. The axillary nerve is affected, and the individual is usually unable to abduct or externally rotate the shoulder joint.

Question 59

Injury to radial nerve motor functions

Answer 59

the triceps brachii and muscles in posterior compartment are affected. The patient is unable to extend at the forearm, wrist and fingers. Unopposed flexion of wrist occurs, known as wrist-drop.

Question 60

Injury to radial nerve sensory functions

Answer 60

all four cutaneous branches of the radial nerve are affected. There will be a loss of sensation over the lateral and posterior arm, posterior forearm, and dorsal surface of the lateral three and a half digits.

Question 61

Injury to median nerve motor functions

Answer 61

Thenar muscles paralysed, as are the lateral two lumbricals. This affects opposition of the thumb and flexion of the index and middle fingers.

Question 62

Injury to median nerve sensory function

Answer 62

Lack of sensation over the areas that the median nerve innervates.

Question 63

Injury to Ulnar nerve motor function

Answer 63

Only the intrinsic muscles of the hand are affected. Abduction and adduction of the fingers cannot occur (due to paralysis of the interossei). Movement of the 4th and 5th digits is impaired (due to paralysis of the medial two lumbricals and hypothenar muscles). Adduction of the thumb is impaired, and the patient will have a positive Froment’s sign (due to paralysis of adductor pollicis).

Question 64

Injury to Ulnar nerve sensory function

Answer 64

All sensory branches are affected, so there will be a loss of sensation over the areas that the ulnar nerve innervates.