Spinal Nerves

Question 1

Week 1-4 of embryology

Answer 1

1- Fertalization, cleavage, implantation

2- Embryoblast development as a bilaminar embryonic disk

3/4- embryogenic stage with 3 embryonic layers

Question 2

3 layers of embryo

Answer 2

ectoderm- dorsal-CNS, PNS, epidermis

Mesoderm- middle- Muscle, bone, blood

Endoderm- ventral- gut tube and glands

Question 3

Neuromere

Answer 3

-elevation in the wall of neural tube where a pair of dorsal + ventral nerves attach

Question 4

Somite

Answer 4

One of the paired cell masses formed in the pariaxial mesoderm next to the neural tube

Question 5

myotome

Answer 5

mesenchymal cells of a somite to for a band of skin innervated by 1 spinal nerve

Question 6

Dermatome

Answer 6

Mesenchymal cells of a somite to form a band of skin innervated by 1 spinal nerve

Question 7

What level does the spinal cord end

Answer 7

l1/2

Question 8

at what level of vertebra protects each portion of the spinal cord

Answer 8

Upper cervical- same bony level
Lower cervical- 1 bony level above
Upper thoracic- 2 bony levels
lower thoracic- 3 bony levels
lumbar- t10/11
sacral- T12/l1
Coccygeal- L1/2

Question 9

Dorsal root function

Answer 9

Sensory

Question 10

Ventral root function

Answer 10

Motor

Question 11

Trunk of the spinal nerve is formed by

Answer 11

unionn of the dorsal and ventral roots

mixed function- sensory +motor

Question 12

C1 nerve is predominatly (function)

Answer 12

Motor

Question 13

What PPR supply the skin AND the intrinsic back muscles

Answer 13

Medial PPR C2-T6

Lateral PPR T7-S3

Question 14

What PPR supply ONLY the intrinsic back muscles

Answer 14

Lateral PPR C2-T6

Medial PPR T7-S3

Question 15

APR function

Answer 15

Mixed nerve; innervation of the skin and muscles of the neck, antero lateral trunk, upper and lower limbs

Question 16

White rami connections level, origin, projection

Answer 16

T1 (c8)- L2(L3)
origin- spinal sympateic center
Paravertebral sympatheic ganglion

Question 17

Gray rami connections, level, origin, projection

Answer 17

All levels
Origin- paravertebral sympathetic ganglion
Projection- axon bundles merge into the APR and PPR to innervate the glands of the skin, blood vessels of skin and arrector pilli muscles

Question 18

Sinuvertebral nerve

Answer 18

After emerging from spinal nerve outside the IVF it looks backwards to the vertebral canal
-innervates dural mater + sleeves

Question 19

The dermatomal contribution to the back is given by the

Answer 19

PPR

Question 20

What is the blood supply of Cervical, Thoracic, Lumbar, Sacral

Answer 20

Cervial- Vertebral A (ascending, deep cervical)

Thoracic- (1-11 post intercostal arteries)

Lumbar- (1st-5th lumbar artery)

Sacral- ( Lateral, Medial sacral)

Question 21

Spinal Ramus- Origin, course, branches (and what they supply)

Answer 21

Origin- Segmental artery

Course- IVF towards vertebral canal

Branches- Spinal nerve will go into canal and split into two radicular arteries

ant. radicular- supplies ventral root of SN
Post. radicular- supplies dorsal root of SN

Question 22

Artery that supplies the lumbosacral enlargement

Answer 22

Adamkiewicz