Neuroanatomy-Organization of the Brain

Question 1

What are cranial meninges?

Answer 1

Cranial meninges are coverings of the brain that lie immediately internal to the calvarium (skull)

Question 2

What are the functions of the cranial meninges? (3)

Answer 2

• Protect the brain
• Form supporting framework for arteries, veins and venous sinuses
• Enclose the subarachnoid space (filled with CSF) which is vital to the normal function of the brain.

Question 3

What are the 3 membranous connective tissue layers? Name their characteristics.

Answer 3

• Dura Mater (dura)- thick, external layer
• Arachnoid Mater (arachnoid)- thin, middle layer
• Pia Mater (pia)- delicate internal vascular layer that is adherent to the surface of the brain

Question 4

What does CSF do? (2)

Answer 4

• Helps maintain the balance of extracellular fluid in the brain
• provides nutrients to the brain in part (but has less protein and different concentrations of sodium, potassium and calcium than blood)

Question 5

What are the Leptomeninges composed of?

Answer 5

The leptomeninges are composed of arachnoid and pia layers.

Question 6

What separates the arachnoid and pia layers?

Answer 6

The arachnoid layer is separated from the pia layer by the subarachnoid space which contains CSF.

Question 7

Dura mater is also called?

Answer 7

Pachymeninges

Question 8

Name the 2 layers of membranes that make up the dura mater.

Answer 8

• External Periosteal Layer- adherent to the inner table of the skull
• Internal Meningeal Layer

Question 9

Name the infoldings of the dura mater and their overall function.

Answer 9

• Falx Cerebri
• Tentorium Cerebelli
• Falx Cerebelli
• Sellar Diaphragm

Inholdings of the dura mater separate regions to help stabilize the position of the brain.

Question 10

Falx Cerebi

Answer 10

Separates the right and left hemispheres and runs along the interhemispheric fissure

Question 11

Tentorium Cerebelli

Answer 11

Separates occipital lobes from the cerebellum

Question 12

Falx Cerebelli

Answer 12

Vertical fold that separates the cerebellar hemispheres

Question 13

Sellar Diaphragm

Answer 13

Smallest dural infolding which covers the pituitary gland and allows the infundibulum of the pituitary to pass through it.

Question 14

Dura mater forms _______ between the _________ and _______ layers of the dura.

Answer 14

Dura mater forms the DURAL VENOUS SINUSES between the PERIOSTEAL and MENINGEAL layers of the dura

Question 15

What is the function of the dural venous sinuses?

Answer 15

The dural venous sinuses provide the venous drainage for the brain and brainstem.

Question 16

Name the dural venous sinuses. (6)

Answer 16

• Superior sagittal sinus
• Inferior sagittal sinus
• Straight sinus
• Confluence of sinuses (torculum)
• Transverse Sinuses
• Sigmoid Sinuses

Question 17

Characteristics of Vasculature of the Dura (2)

Answer 17

• most dural branch arteries supply more blood to the calvarium the the dura.
• the largest is the middle meningeal artery (branch of the maxillary artery) which enters the middle cranial fossa via foramen spinosum

Question 18

Venous drainage

Answer 18

-drainage of the dura via dural emissary veins, which travel alongside the meningeal arteries and drain into the dural venous sinuses.

Question 19

Nerve supply to the dura is by which nerve(s)?

Answer 19

From the meningeal branches of all 3 divisions of the trigeminal nerve (CN V) - ophthalmic (V1), Maxillary (V2) and Mandibular (V3).

Question 20

Space between the cranium and the periosteal layer of the dura.

Answer 20

Space between the cranium and the periosteal layer of the dura.

Question 21

Epidural Hematoma

Answer 21

Epidural hematoma is the filling of blood in the epidural space following head trauma most often associated with the tearing of the meningeal arteries.

Question 22

Subdural Hematoma

Answer 22

Subdural Hematoma is the filling of blood wishing the subdural space following head trauma most often associated with the tearing of the emissary (bridging) veins

Question 23

Space between the arachnoid and pia layers

Answer 23

Subarachnoid Space

Question 24

Most common problems involving the subarachnoid space

Answer 24

Free blood within secondary to trauma or a ruptured aneurysm

Question 25

Spaces considered to be a “potential space” meaning the space only becomes a space pathologically

Answer 25

• Epidural Space

- Subdural Space

Question 26

Space considered a “real space” meaning it contains CSF, arteries and veins

Answer 26

Subarachnoid space