Nerve Root Dermatomes, Myotomes, Reflexes

Question 1

C1 Dermatome

Answer 1

Vertex of skull

Question 2

C2 dermatome

Answer 2

Temple, forehead, occiput

Question 3

C2 myotome (muscle weakness)

Answer 3

1. Longus colli
2. SCM
3. Rectus capitis

Question 4

C3 dermatome

Answer 4

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

Question 5

C3 Myotome (muscle weakness)

Answer 5

Trapezius, selenium capitis

Question 6

C3 Paresthesias

Answer 6

Cheek and side of neck

Question 7

C4 dermatome

Answer 7

Shoulder area, clavicular area, upper scapular area

Question 8

C4 myotome (muscle weakness)

Answer 8

Trapezius, levator scapulae

Question 9

C4 paresthesia

Answer 9

Horizontal band along clavicle and upper scapula

Question 10

C5 dermatome

Answer 10

Deltoid area, Anterior aspect of entire arm to base of thumb

Question 11

C5 myotome (muscle weakness)

Answer 11

Supraspinatus, infraspinatus, deltoid, biceps

Question 12

C5 Reflexes affected

Answer 12

Biceps, brachioradialis

Question 13

C6 dermatome

Answer 13

Anterior arm, radial side of hand to thumb and index finger

Question 14

C6 myotome (muscle weakness)

Answer 14

Biceps, Supinator, wrist extensors

Question 15

C6 reflex affected

Answer 15

Biceps, brachioradialis

Question 16

C6 parasthesias

Answer 16

Thumb and index finger

Question 17

C7 dermatome

Answer 17

Lateral arm and forearm to index, long, and ring fingers

Question 18

C7 myotome (muscle weakness)

Answer 18

Triceps, wrist flexors (rarely wrist extensors)

Question 19

C7 reflexes affected

Answer 19

Triceps

Question 20

C7 paresthesias

Answer 20

Index, long and ring fingers

Question 21

C8 dermatome

Answer 21

Medial arm and forearm to long, ring, and little fingers

Question 22

C8 myotome (muscle weakness)

Answer 22

Ulnar debaters, thumb extensors, thumb adductors (rarely triceps)

Question 23

C8 Parasthesias

Answer 23

Little finger alone or with tow adjacent fingers; not ring or long fingers, alone or together (C7)

Question 24

T1 dermatome

Answer 24

Medial side of forearm to base of little finger

Question 25

T1 myotome, reflex affected, and paresthesias

Answer 25

Disk lesions at upper 2 thoracic Levels do not appear to give rise to root weakness. Weakness of intrinsic muscles of the hand is due to other pathology (e.g. thoracic outlet pressure, neoplasm of lung, ulnar nerve lesion)

Question 26

T2 dermatome

Answer 26

Medial Side of upper arm to medial elbow, pectoral and midscapular areas

Question 27

T3-T12 dermatomes

Answer 27

T3-T6: upper thorax T5-T7: costal margin T8-T12: abdomen and lumbar region

Question 28

T3-T12 myotomes, affected reflexes, parasthesias

Answer 28

Articular and dural signs and root pain are common. Root signs (cutaneous analgesia) are rare and have such indefinite area that hey have little localizing value. Weakness is not detectable

Question 29

L1 dermatome

Answer 29

Back, over trochanter and growing

Question 30

L1 parasthesia

Answer 30

Groin; after holding posture which causes pain

Question 31

L2 dermatome

Answer 31

Back, front of thigh to knee

Question 32

L2 myotome (muscle weakness)

Answer 32

Psoas, hip adductors

Question 33

L2 parasthesias

Answer 33

Occasionally anterior thigh

Question 34

L3 dermatome

Answer 34

Back, upper buttock, anterior thigh and knee, medial lower leg

Question 35

L3 myotome (muscle weakness)

Answer 35

Psoas, quadriceps, thigh atrophy

Question 36

L3 Reflexes affected

Answer 36

Knee jerk sluggish, PKB positive, pain on full SLR

Question 37

L3 paresthesias

Answer 37

Medial knee, anterior lower leg

Question 38

L4 dermatome

Answer 38

Meidal buttock, lateral thigh, medial leg, dorsum of foot, big toe

Question 39

L4 myotome (Muscle weakness)

Answer 39

Tibial is Anterior, extensor Hallucis

Question 40

L4 reflexes affected

Answer 40

SLR limited, neck flexion pain, weak or absent knee jerk, side flexion limited

Question 41

L4 paresthesias

Answer 41

Medial aspect of calf and ankle

Question 42

L5 dermatome

Answer 42

Buttock, posterior and lateral thigh, lateral aspect of leg, dorsum of foot, medial half of sale, first, second, and third toes

Question 43

L5 myotome (muscle weakness)

Answer 43

Extensor hallucis, peroneals, gluteus medius, dorsiflexors, hamstrings and calf atrophy

Question 44

L5 Reflexes affected

Answer 44

SLR limited one side, neck flexion painful, decreased ankle, crossed-leg raising pain

Question 45

L5 paresthesias

Answer 45

Lateral aspect of leg, medial three toes

Question 46

S1 dermatome

Answer 46

Lateral and plantar aspect of foot

Question 47

S1/S2 myotome (muscle weakness)

Answer 47

Calf and hamstrings, washing of gluteals, peroneals, plantar flexors

Question 48

S1/S2 Reflexes affected

Answer 48

SLR limited, Achilles reflex weak or absent

Question 49

S1 paresthesias

Answer 49

Lateral two toes, lateral foot, lateral leg to knee, plantar aspect of foot

Question 50

S3 dermatomes

Answer 50

Groin, posteromedial thigh to knee

Question 51

S4 dermatomes

Answer 51

Perineum, genitals, lower sacrum

Question 52

S4 myotomes (muscle weakness)

Answer 52

Bladder, rectum

Question 53

S4 parasthesia

Answer 53

saddle area, genitals, anus, impotence, massive posterior herniation

Question 54

S2 dermatome

Answer 54

Buttocks, thigh, and posterior leg

Question 55

S2 parathesia

Answer 55

Lateral leg, knee, heel