Anatomy of Space Occupying Lesions

Question 1

Can the skull expand?

Answer 1

Not really = more able to do it when younger, capable of slow rate expansion

Question 2

Do the base of skull foraminae allow the contents of the skull to escape?

Answer 2

Not really

Question 3

What is a space occupying lesion?

Answer 3

Abnormal tissue taking up space = acute or subacute intracranial pathologies can be considered SOLs

Question 4

What can space occupying limits result in?

Answer 4

Raised ICP = can lead to herniation

Question 5

What gives sensory innervation to the dura mater?

Answer 5

Mostly CN V

Question 6

What does the dura mater adhere to?

Answer 6

The internal aspect of the skull

Question 7

What are the two layers of the dura mater?

Answer 7

Peri-ostial layer = layer closest to bone

Meningeal layer = attached to the arachnoid mater

Question 8

What is the diaphragm sellae?

Answer 8

Tough sheet of dura mater forming a roof over the pituitary fossa

Question 9

What is the tentorium cerebelli?

Answer 9

Sheet of dura mater tenting over the cerebellum = attaches to ridges of petrous temporal bones and has central gap for the brainstem

Question 10

What is the falx cerebri?

Answer 10

Midline structure made of dura mater = separates right and left cerebral hemispheres

Question 11

What are the attachments of the falx cerebri to the deep aspects of the skull?

Answer 11

Anteriorly = crista gali of ethmoid bone
Posteriorly = internal aspect of sagittal suture, internal occipital protuberance

Question 12

Where do the cerebral veins drain blood from?

Answer 12

Drain venous blood from brain into dural venous sinuses

Question 13

Where is the confluence of sinuses in the brain?

Answer 13

In the midline at the lateral occipital protuberance

Question 14

What are some features of the sigmoid sinus?

Answer 14

S shaped

Ends at the jugular foramen

Question 15

How do you treat hydrocephalus?

Answer 15

Using a ventricular peritoneal shunt

Question 16

Where does the external carotid artery supply?

Answer 16

Stays outside cranial cavity to supply to neck, face and scalp

Question 17

How does the internal carotid artery enter the cranial cavity to supply the brain?

Answer 17

Via the carotid canal

Question 18

How does the vertebral artery enter the cranial cavity?

Answer 18

Passes through the transverse foraminae in the first six cervical vertebrae then through the foramen magnum

Question 19

Where is the arterial supply to the brainstem and cerebellum located?

Answer 19

Inferior to midbrain, closely related to the pituitary stalk and optic chiasm within the subarachnoid space

Question 20

Where do the posterior cerebral arteries supply?

Answer 20

Most of the inferior aspect of the brain and the cerebellum

Question 21

What artery supplies the visual cortex?

Answer 21

The right posterior cerebral artery

Question 22

Where do the middle cerebral arteries supply?

Answer 22

Lateral aspect of the brain and the temporal lobe

Question 23

Where do the anterior cerebral arteries supply?

Answer 23

The medial aspect of the brain and the frontal lobe

Question 24

What are the terminal branches of the internal carotid artery?

Answer 24

Anterior and middle cerebral arteries

Question 25

What surrounds the Circle of Willis?

Answer 25

Cerebrospinal fluid

Question 26

What forms the basilar artery?

Answer 26

The left and right vertebral arteries

Question 27

What are some features of an extradural haemorrhage?

Answer 27

Between the bone and dura

May be due to ruptured meningeal artery or trauma to pterion

Question 28

What are some features of a subdural haemorrhage?

Answer 28

Into epidural space between dura and arachnoid
Due to torn cerebral veins
May have been caused by fall in the elderly

Question 29

What are some features of a subarachnoid haemorrhage?

Answer 29

Into CSF of the subarachnoid space

May be due to ruptured Circle of Willis (berry) aneurysm or congenital aneurysm

Question 30

What are the potential patterns of infratentorial herniation?

Answer 30

Upward

Downward/tonsillar = cerebellar tonsils herniate into foramen magnum

Question 31

What are the potential patterns of supratentorial herniation?

Answer 31

Cingulate, central, transcavarial, uncal/transtentorial

Question 32

What occurs in an uncal supratentorial herniation?

Answer 32

Uncus of temporal lobe herniates inferior to tentorium cerebelli = compresses CN III to cause ipsilateral fixed pupil