peripheral nerve

Question 1

what are 1a fibers

Answer 1

A-alpha; large ALPHA motor neurons in lamina IX

Question 2

what are 1b fibers

Answer 2

a-alpha; sensory fibers; Golgi tendon organs, touch & pressure receptors

Question 3

what are II fibers

Answer 3

two types -> 1) A-beta = sensory, secondary afferents (flower sprays) of muscle spindles, crude touch, pressure receptors, pacinian corpuscles (vibratory)

2) a-gamma = motor, small gamma neurons of lamina IX (intrafusal)

Question 4

what are iii fibers

Answer 4

1) a-delta = sensory, small lightly myelinated, fine touch, pressure, pain and temp
2) B = motor, small, lightly myelinated PREGANGLIONIC AUTONOMIC FIBERS

Question 5

what are IV fibers

Answer 5

C fibers = motor (post-ganglionic neurons); sensory, UNMYELINATED, pain and temp to spinothalamic tract; slow speed

Question 6

fasciculations vs fibrillations

Answer 6

fasciculations are visible muscle contractions to naked eye; fibrillations are only detectable via EMG

Question 7

muscles innervated by dorsal scapular n

Answer 7

levator scapulae, rhomboids

Question 8

muscle innervated by suprascapular n

Answer 8

supraspinatus, infraspinatus

Question 9

muscles innervated by thoracodorsal n

Answer 9

latissimus dorsi

Question 10

muscles innervated by subscapular n

Answer 10

subscapularis

Question 11

muscles innervated by axillary n

Answer 11

deltoid, teres minor

Question 12

muscles innervated by musculocutaneous n

Answer 12

biceps brachii, coracobrachialis, brachialis

Question 13

muscles innervated by ulnar nerve

Answer 13

1) flexor carpi ulnaris
2) FDP III and IV
3) adductor pollicus
4) abductor pollicus minimi
5) opponens pollicus minimi
6) flexor digiti minimi brevis
7) dorsal and palmar interossei
8) lumbricals III and IV

Question 14

muscles innervated by median nerve proper

Answer 14

1) pronator teres
2) flexor carpi radialis
3) palmaris longus
4) flexor dig superficialis
5) abductor pollicis brevis
6) flexor pollicis brevis
7) opponens pollicus
8) lumbricals I and II

Question 15

muscles innervated by anterior interosseous nerve (branch of median nerve)

Answer 15

1) pronator quadratus
2) flexor dig profundum I and II
3) flexor pollicus longus

Question 16

muscles innervated by radial nerve

Answer 16

1) triceps brachii
2) brachioradialis
3) extensor carpi radialis
4) supinator

Question 17

muscles innervated by posterior interosseous nerve (branch of radial n)

Answer 17

1) extensor digitorum
2) abductor pollicus longus
3) extensor pollicus brevis and longus
4) extensor indicis proprius

Question 18

what tendons are involved in de Quervains tenosynovitis?

Answer 18

abductor pollicus longus and extensor pollicus brevis

Question 19

in nerve injury, presence of a nerve action potential indicates

Answer 19

that surgical repair is unlikely needed

Question 20

24 month rule of peripheral nerve repair

Answer 20

after 24 months of denervation, most muscles cannot recover useful function even with reinnervation

Question 21

roots that contribute to brachial plexus

Answer 21

ventral rami of C4-T1; mostly C5-T1

Question 22

roots involved in radial nerve, median nerve, ulnar nerve, axillary nerve

Answer 22

1) radial n -> C5-C8
2) median n -> C5-T1
3) axillary n -> C5, C6
4) ulnar n -> C8, T1