Myotomes, Dermatomes, Reflexes

Question 1

Myotome definition

Answer 1

group of muscles innervated by a single spinal nerve root

Question 2

Myotome clinical use

Answer 2

determine if damage has occurred to spinal cord and which level

Question 3

Myotome C1-C2

Answer 3

cervical flexion

Question 4

Myotome C3

Answer 4

cervical side bend

Question 5

Myotome C4

Answer 5

shoulder shrug

Question 6

Myotome C5

Answer 6

shoulder abduction

Question 7

Myotome C6

Answer 7

elbow flexion + wrist extension

Question 8

Myotome C7

Answer 8

elbow extension + wrist flexion

Question 9

Myotome C8

Answer 9

thumb extension + ulnar deviation

Question 10

Myotome T1

Answer 10

finger abduction

Question 11

Dermatome definition

Answer 11

area of skin supplied by a single nerve root

Question 12

Dermatome - what causes loss of muscle tone and mass

Answer 12

pressure on the roots - not as obvious as on peripheral nerves; more muscle fibers are more likely to be affected + have evident wasting/atrophy

Question 13

Dermatome C1

Answer 13

vertex of skull

Question 14

Dermatome C2

Answer 14

temple, forehead, occiput

Question 15

Dermatome C3

Answer 15

entire neck, posterior cheek, temporal area, prolongation forward under mandible

Question 16

Dermatome C4

Answer 16

shoulder area, clavicular area, upper scap area

Question 17

Dermatome C5

Answer 17

deltoid area, ant aspect of entire arm to base of thumb

Question 18

Dermatome C6

Answer 18

ant arm, radial side of hand to thumb and index fingers

Question 19

Dermatome C7

Answer 19

lat arm + forearm to long, ring, and little fingers

Question 20

Dermatome C8

Answer 20

med arm of forearm to long, ring, and little fingers

Question 21

Dermatome T1

Answer 21

med arm of forearm to base of little finger

Question 22

Dermatome T2

Answer 22

med side of upper arm to elbow, pect, and mid scap area

Question 23

Dermatome T3 - T6

Answer 23

upper thorax

Question 24

Dermatome T5 - T7

Answer 24

costal margin

Question 25

Dermatome T8 - T12

Answer 25

abdomen + lumbar

Question 26

Dermatome L1

Answer 26

back over trochanter and groin

Question 27

Dermatome L2

Answer 27

back, front of thigh to knee

Question 28

Dermatome L3

Answer 28

back, upper butt, ant thigh and knee, med lower leg

Question 29

Dermatome L4

Answer 29

med butt, lat thigh, med leg, dorsum of foot, big toe

Question 30

Dermatome L5

Answer 30

butt, post and lat thigh, lat aspect of leg, dorsum of foot, medial 1/2 of sole, 1-3 toes

Question 31

Dermatome S1 - S2

Answer 31

butt, thigh, post leg

Question 32

Dermatome S3

Answer 32

groin med thigh to knee

Question 33

Dermatome S4

Answer 33

perineum, genitals, lower sacrum

Question 34

Deep tendon reflexes biceps and brachioradialis levels

Answer 34

C5 - C6

Question 35

Deep tendon reflexes triceps levels

Answer 35

C7 - C8

Question 36

Deep tendon reflexes patellar levels

Answer 36

L2 - L4

Question 37

Deep tendon reflexes achilles tendon levels

Answer 37

S1 - S2

Question 38

Deep tendon reflexes hamstrings levels

Answer 38

L5 - S2

Question 39

Deep tendon reflexes 0 score

Answer 39

no response, always abnormal (absent/areflexia)

Question 40

Deep tendon reflexes 1+ score

Answer 40

slight reflex, present but depressed, low normal (diminished/hyporeflexia)

Question 41

Deep tendon reflexes 2+ score

Answer 41

normal, typical reflex

Question 42

Deep tendon reflexes 3+ score

Answer 42

brisk reflex, possibly but not necessarily abnormal (exaggerated/brisk)

Question 43

Deep tendon reflexes 4+ score

Answer 43

very brisk reflex, abnormal, clonus (hyperactive; hyperreflexia)

Question 44

Superficial reflex - corneal reflex

Answer 44

involuntary blinking in response to corneal stimulation afferent = ophthalmic branch (VI) of trigeminal n (CN V) efferent = facial n. (CN VII)

Question 45

Superficial reflex - abdominal reflex (T7 - T12)

Answer 45

contraction of superficial abdominal muscles when stroking (lat to med) abdomen lightly (+) asymmetric; UMN lesion on absent side

Question 46

Superficial reflex - cremastic reflex (L1, L2)

Answer 46

contraction of cremaster muscle (pulls scrotum/testis up) after stroking same side of superior/inner thigh (+) absent; SCI or corticospinal lesions

Question 47

Superficial reflex - plantar reflex (S1 - S2 = tibial n)

Answer 47

PF of toes elicited when stroking lateral sole of foot from calcaneus to base of 5th metatarsal (+) Babinski (DF = 1st; spanning = 2nd-5th); corticospinal/UMN lesions

Question 48

Superficial reflex - anal reflex

Answer 48

reflexive contraction of external anal sphincter upon stroking skin around anus afferent = pudenal n efferent = S2 - S4

Question 49

Superficial reflex - bulbocavernous reflex (S2 - S4)

Answer 49

anal sphincter contraction in response to squeezing glans penis/tugging on an indwelled foley catheter 1st reflex to come after SCI --> body out of spinal shock