Lecture 18: Anatomy and Function of the Spinal Cord and Spinal Nerves

Question 1

Where does the spinal cord start?

Answer 1

At the Foramen magnum, the big hole at the base of the skull.

Question 2

Where does the spinal cord end?

Answer 2

The inferior border of the first lumbar vertebra.

Question 3

What is the spinal cord surrounded by?

Answer 3

It’s within a sac that fits inside the spinal cavity containing spinal fluid. (Within vertebrae)

Question 4

What are the anterior and posterior sides of the spine called?

Answer 4

Ventral (anterior) and dorsal (posterior).

Question 5

The spinal cord ends in a tapered cone. What is this called?

Answer 5

Conus medularis

Question 6

What is the meninges?

Answer 6

3 layers of protective tissue surrounding the brain and spinal cord.

Question 7

What is the roles of the Filium terminale?

Answer 7

Extends from the conus medullaris to the end of the spinal cavity, anchoring the spinal cord - an extension of the meninges.

Question 8

At what vertebral level does the spinal cord end?

Answer 8

Around the L1 / L2 vertebral level.

Question 9

What are the divisions of the spinal cord?

Answer 9

Cervical (C1-C7)
Thoracic (T1-T12)
Lumbar (L1-L5)
Sacral (S1-S5)

Question 10

Which nerves make up the Cauda equina?

Answer 10

Spinal nerves that exit the spinal cavity inferior to the end of the spinal cord.

Question 11

What is Grey matter and White matter?

Answer 11

Grey matter is cell bodies and white matter is myelinated axons.

Question 12

What is a sulcus and a fissure?

Answer 12

A sulcus is a furrow, a fissure is a deep sulcus.

Question 13

Which is deeper, the posterior median sulcus or the anterior median fissure?

Answer 13

The anterior median fissure.

Question 14

What type of matter do the dorsal and ventral columns consist of?

Answer 14

White matter.

Question 15

What type of matter do the dorsal and ventral horns consist of?

Answer 15

Grey Matter.

Question 16

Are the dorsal and ventral nerve roots part of the PNS or CNS?

Answer 16

PNS

Question 17

Which parts of the spinal cord does information travel up, and down?
(roots and horns)

Answer 17

Afferent, sensory info goes up the dorsal root and dorsal horn. Efferent, motor, info comes down the ventral horn and ventral root.

Question 18

Are ventral root axons myelinated?

Answer 18

Yes.

Question 19

What type of matter are the spinal cord columns made of?

Answer 19

White matter.

Question 20

What direction is information travelling in the lateral, anterior and posterior columns of the spinal cord?

Answer 20

Posterior: Afferent
Anterior: Efferent
Lateral: Both.

Question 21

What type of neurons leave the spinal cord by the ventral horns?

Answer 21

Somatic motor neurons.

Question 22

What type of neurons leave the spinal cord by the lateral horns?

Answer 22

Autonomic

Question 23

What would happen if somatic motor neurons were damaged?

Answer 23

Paralysis - muscles won’t contract.

Question 24

What is the dorsal root ganglion?

Answer 24

The cell bodies of sensory neurons.

Question 25

What would happen the dorsal horn of the spinal cord was damaged?

Answer 25

Loss of sensation. No sensory info.

Question 26

What is a spinal nerve?

Answer 26

A combination of dorsal and ventral nerve roots - 2 way flow of information. Also called ‘mixed nerves’.

Question 27

What happens to spinal nerves when the leave the spinal column?

Answer 27

The break back into two branches - ventral ramus and dorsal ramus.

Question 28

What does ramus mean?

Answer 28

Branch

Question 29

Are PNS nerve axons myelinated or not?

Answer 29

Some are, some aren’t.

Question 30

Explain the structure of a peripheral nerve, in terms of their coverings and bundles.

Answer 30

Axons may be covered in myelin, which are covered in endoneurium. These covered axons are bundled to form fascicles, which are covered in perineurium. These fascicles are bundled, with blood vessels, to for a nerve. Nerve is covered in epineurium.

Question 31

What is a tract?

Answer 31

Bundles of nerves in the CNS