Spinal Cord

Question 1

Neurulation

Answer 1

rudiments of CNS develop from ectoderm

Question 2

Development of Neural Tube

Answer 2

1. neuroectodermal tissues differentiate from ectoderm and thicken into neural plate
2. neural plate bends/folds dorsally; two ends join at neural plate borders (neural crest)
3. closure of neural tube disconnects neural crest from epidermis
4. neural crest cells differentiate to form PNS
5. notochord degenerates and persists as nucleus pulposus

Question 3

Spina Bifida

Answer 3

disorder in which the two sides of vertebral arches fail to fuse during development, resulting in an “open” vertebral canal

Question 4

Types of Spina Bifida

Answer 4

• occulta: defect in vertebral arch of L5 or S1, asymptomatic w/ a tuft of hair
• severe: defect allows a large outpouching of meninges

Question 5

Meningocele

Answer 5

outpouching of meninges that contains cerebrospinal fluid

Question 6

Myelomeningocele

Answer 6

outpouching of meninges that contains a portion of the spinal cord

Question 7

Spinal Nerves

Answer 7

• originate at spinal cord and connects PNS to CNS
• 31 pairs = 8 cervical, 12 thoracic, 5 lumbar, 5 sacral, 1 coccygeal

Question 8

How do the spinal nerves exit?

Answer 8

cervical region: run up
thoracic & lumbar region: run down

Question 9

Nerve Roots

Answer 9

ventral = motor
dorsal = sensory

Question 10

Rami Innervation

Answer 10

ventral = ventral body wall, extrinsic back, all limbs
dorsal = skin, deep muscles of back

Question 11

Myotomes

Answer 11

the muscles supplied by an individual spinal nerve

Question 12

C5

Answer 12

shoulder flexion, scaption, abduction, and external rotation

Question 13

C6, C7, C8

Answer 13

shoulder extension, adduction, and internal rotation

Question 14

Myotome Actions (UE)

Answer 14

C5 - shoulder flexion
C6 - elbow flexion
C7 - wrist flexion
C8 - finger flexion
T1 - finger abduction

Question 15

Dermatomes

Answer 15

area of skin supplied by an individual spinal nerve; used to assess level of SCI and ortho herniated nucleus pulposus (HNP)

Question 16

Cauda Equina

Answer 16

spinal cord terminates b/w L1/L2 vertebral level and forms a bundle of nerves

Question 17

Spinal Meninges Order

Answer 17

epidural space > dura mater (outer) > subdural space > arachnoid mater (veins) > subarachnoid space (contains CSF) > pia mater (inner, thinnest)

Question 18

Spinal Ligaments

Answer 18

1. anterior longitudinal ligament (front of vertebral body)
2. posterior longitudinal ligament (back of vertebral body, front of canal)
3. nuchal ligament
4. flava ligament (back of canal)
5. interspinous ligament (b/w SP)
6. supraspinous ligament (over SP)

Question 19

Tight Pectoralis Minor

Answer 19

chronic tightness can lead to anterior tipping of the scapula; “pseudo” inferior angle winging

Question 20

Arterial Supply

Answer 20

ABC’s
heart > aorta > brachiocephalic trunk > common carotid artery > subclavian artery