Nervous system: The cerebellum and spinal cord

Question 1

Where is the vermis and what is its function?

Answer 1

The centre of the cerebellum

Thought to be involved in controlling trunk musculature

Question 2

What is the clinical relevance of the cerebellum tonsils?

Answer 2

In raised intracranial pressure they can herniate through the foramen magnum and exert pressure onto the midbrain

Question 3

What are the cerebellar peduncles?

Answer 3

Two flattened areas either side of the cerebellum which make contact with the brainstem

• the superior portion of the peduncle connects the midbrain
• the middle connects to the pons
• inferior attaches to the medulla

Question 4

What are the meningeal layers of the spinal cord?

Answer 4

Pia mata
Arachnoid mata
Dura mata

Question 5

What are the functions of the dorsal and ventral roots of the spinal cord?

Answer 5

Dorsal root - carries sensory fibres (the cell body is within the dorsal root ganglion)
Ventral root - carrier motor fibres

Question 6

Why is there cervical and lumbar enlargement of the spinal cord?

Answer 6

The enlargements are due to the attachment of large nerves controlling the upper and lower limbs.

Question 7

What is the cona medullaris?

Answer 7

The tapered, lower end of the spinal cord.

Gets thinner due to spinal nerves progressively branching out

Question 8

What is the cauda equina?

What is cauda equina syndrome?

Answer 8

A bundle of spinal nerves which provide innervation to the pelvic region and lower limb.
Cauda equina syndrome is a surgical emergency - can result in paralysis or permanent loss of sensation if not treated. Caused by compression of the spinal roots, most commonly by a herniated disc.

Question 9

What is the filum terminale?

Answer 9

A thin band of fibrous tissue which is a continuation of the pia mata. Provides longitudinal support for the spinal cord

Question 10

What is the lumbar cistern?

What is its clinical use?

Answer 10

A cistern is a space where the pia mata and arachnoid mata are separated forming a space filled with CSF. The lumbar cistern extends from L1-S2 and contains the filum terminale and roots of the cauda equina.
Used clinically as the site of lumbar puncture.

Question 11

What are the different types of spina bifida?

Answer 11

Oculata: vertebrae are not formed properly but the opening is covered by skin so not visible.
Closed neural tube defects: spinal cord has malformations of fat, bone or membranes. Few symptoms.
Meningocele: there is a lump formed by the bulging meninges, filled with CSF.
Myelomeningocele: most severe. The spinal cord itself protrudes causing paralysis below that level.

Question 12

How does taking folic acid during pregnancy help to prevent spina bifida?

Answer 12

Folic acid is important for the folding and closure of the neural tube. Spina bifida results from the neural tube failing to close. (cleft palate is also associated with folate deficiency in pregnancy)

Question 13

When is it recommended for mothers-to-be to begin taking folic acid supplements?

Answer 13

As folding and closure of the neural tube takes place in week 4, when a women may not even know she is pregnant, it is recommended to being folic acid supplements when trying for a baby.

Question 14

How can a dilated ventricle be treated?

Answer 14

A shunt can be inserted to drain CSF from the ventricle into the peritoneum.

Question 15

Which region of the cortex sits anterior to the central sulcus?

Answer 15

The primary motor cortex

Question 16

In which space to CSF circulate?

Answer 16

The subarachnoid space

Question 17

What are the clinical signs of a cerebellar stroke?

Answer 17

D - dysdiadochokinesia 
A - ataxia 
N - nystagmus 
I - intention tremor 
S - scanning dysarthria 
H - heel shin test is positive 

(Signs in the cerebellum are ipsilateral)

Question 18

What separates the cerebellum from the occipital and parietal lobes?

Answer 18

The tentorium cerebelli

Question 19

What is the function of the cerebellum?

Answer 19

Motor control and coordination

Question 20

What is the major arterial blood supply of the spinal cord?

Answer 20

Anterior spinal artery which runs in the anterior sulcus the entire length of the cord.
Two posterior spinal arteries.
They are fed with blood from segmental vessels from the aorta, but at the top of the cord the anterior spinal artery also arises as a confluence of the two vertebral arteries.

Question 21

Which artery is vulnerable during aortic aneurysm repair?

Answer 21

The artery of adamkiewicz - major tributary of the segmental arteries supplying the lower cord.