12 - PNS and Motor System: the Motor Unit

Question 1

What levels give off a white communicating ramus to a sympathetic trunk ganglion?

Answer 1

Thoracic and upper lumbar

Question 2

Arm supplied dermatomes

Answer 2

C5-T1

Question 3

Trunk supplied dermatomes

Answer 3

T dermatomes

Question 4

Nipple line supplied dermatome

Answer 4

T4/T5

Question 5

Umbilicus supplied dermatome

Answer 5

T10

Question 6

Leg supplied dermatomes

Answer 6

L1-S2

Question 7

Saddle supplied dermatomes

Answer 7

S2-S5

Question 8

Perianal region supplied dermatomes

Answer 8

S3-S5

Question 9

Upper extremity myotomes

Answer 9

C5-T1

Question 10

Lower extremity myotomes

Answer 10

L1/L2-S2

Question 11

Describe the pathway of the somatic motor fiber

Answer 11

Ventral horn -> ventral root

Question 12

Describe the pathway of sympathetic visceral motor fibers

Answer 12

(From T1-L3) Lateral horn cell -> ventral root -> spinal nerve -> white communicating ramus -> symp. paravertebral ganglion -> grey communicating ramus -> w/ somatic efferent fibers

Question 13

Describe the pathway of parasympathetic visceral motor fibers

Answer 13

(From S2-S4) Ventral root -> pelvic nerves (should be similar to symp. visc. motor fibers)

Question 14

Describe the pathway of somatic and visceral sensory fibers

Answer 14

Enter by dorsal root -> DRG

Question 15

From the outside inwards, name the parts of a peripheral nerve fiber

Answer 15

Epineurium > perineurium > fascicles > endoneurium > Schwann cells > nerve