Anatomy of the spinal cord and vertebral column

Question 1

What are the layers of the spinal meninges?

Answer 1

• Dura mater
• Arachnoid mater
• Pia mater

Question 2

Describe the dura mater

Answer 2

Thick inelastic outer covering
Richly innervated by sensory nerve endings
Surrounds spinal cord from fusion at cranium down to the level of S2 vertebra

Provides maximum protection to the cord

Question 3

What is the epidural space?

Answer 3

Also known as extradural space

Space between the vertebral canal walls and the spinal dural sac. It contains fat and blood vessels.

Question 4

Describe the arachnoid mater

Answer 4

Lies beneath dura mater (not connected)
Avascular
Extends to the level of S2 vertebra
Bridges the subarachnoid space with small filaments

Question 5

Describe the pia mater

Answer 5

thin inner layer
intimately covers the cord
At cervical and thoracic levels = denticulate ligaments

Question 6

What are the denticulate ligaments?

Answer 6

Small ligaments that extend laterally and help anchor the cord to the dural sac

Question 7

What happens to the pia mater at the conus medullaris?

Answer 7

Forms the terminal filum, a single cord of tissue that pierces the dural sac at the S2 vertebral level, acquires a dural covering, and then attaches to the coccyx to anchor the spinal cord inferiorly

Question 8

What is the subarachnoid space?

Answer 8

A space between the arachnoid mater and the pia mater that is filled with CSF

Question 9

Where is CSF secreted?

Answer 9

Choroid plexus

Question 10

Where is CSF absorbed?

Answer 10

arachnoid granulations and secondarily by small veins on the surface of the pia mater

Question 11

How much CSF is produced per day?

Answer 11

~500ml

Question 12

What is the dorsal root ganglion?

Answer 12

A collection of neurons in the periphery

Usually contains a sensory pseudounipolar neuron

Question 13

What is the dorsal ramus?

Answer 13

A small ramus that courses dorsally to the back and conveys motor and sensory information to and from the skin and the intrinsic back muscles and suboccipital skeletal muscles

Question 14

What is the ventral ramus?

Answer 14

A much larger ramus that courses laterally and ventrally and innervates all the remaining skin and skeletal muscles of the neck, limbs and trunk.

Question 15

What is the cauda equina

Answer 15

The bundle of nerve roots below the level of the conus medullaris.
Cauda equina = horse’s tail

Question 16

What is the terminal filum?

Answer 16

The pial extension that anchors the spinal cord inferiorly to the coccyx.

Question 17

Where is the ventral aspect?

Answer 17

Towards the body of the vertebrae (abdominal region)

Question 18

Where is the dorsal aspect?

Answer 18

Towards the spinous processes of the vertebrae (the back region)

Question 19

Where is grey matter derived from?

Answer 19

The alar plate

Question 20

What are the different areas of the grey matter?

Answer 20

• Dorsal horn
• Intermediate horn
• Ventral horn

Question 21

What are the different areas of the white matter

Answer 21

• Dorsal funiculus
• Lateral funiculus
• Ventral funiculus

Question 22

What areas of the body does the cervical spine innervate?

Answer 22

The neck, upper chest and most of the forearms

Question 23

What areas of the body does the thoracic spine innervate?

Answer 23

The trunk, thin strips down both forearms

Question 24

What areas of the body does the lumbar spine innervate?

Answer 24

The lower limbs

Question 25

What areas of the body does the sacral spine innervate?

Answer 25

The genitalia

Question 26

Describe the white/grey matter distribution in the cervical region of the spinal cord

Answer 26

Dorsal and ventral horns within grey matter relatively large as supplying the limbs

Question 27

Describe the white/grey matter distribution in the thoracic region of the spinal cord

Answer 27

Dorsal and ventral horns within grey matter relatively small as relatively insensitive in chest and abdomen, and muscle groups do not need fine motor control

Question 28

Describe the white/grey matter distribution in the lumbar region of the spinal cord

Answer 28

Dorsal and ventral horns within grey matter relatively large as supplying the limbs

Question 29

Describe the white/grey matter distribution in the sacral region of the spinal cord

Answer 29

Dorsal and ventral horns pretty equal in size but smaller relative to cervical and lumbar regions

Question 30

What is a spinal segment?

Answer 30

The region of the spinal cord that contains a pair of nerve roots that innervates the corresponding dermatome and myotome

Question 31

What is CSF

Answer 31

A filtrate of blood that affords mechanical and immunological protection to the brain and spinal cord

Question 32

What are Baston veins?

Answer 32

A venous plexus that runs the entire length of the spinal column within the epidural space

Question 33

What are the key features of Baston veins?

Answer 33

They do not contain any valves

Question 34

Name the main arterial supply to the spinal cord

Answer 34

• Vertebral arteries
• Ascending cervical arteries
• Posterior intercostal arteries
• Lumbar arteries
• Lateral sacral arteries

Question 35

What is the artery of Adamkiewicz?

Answer 35

The largest segmental artery that is found in the lower thoracic or upper lumbar region.

Major blood supply for the lower 2/3 of the cord

Question 36

Describe the arterial supply to the spinal cord

Answer 36

Largely on a segmental basis.
A single anterior spinal artery and two posterior spinal arteries

The aorta sits anteriorly

You’ll get segmental arteries at the various intercostal levels and these will branch off and fuse to supply the spinal cord itself.