Overview of Meninges

Question 1

Which of the following meningeal layers closely adheres to the surfaces of the brain and allows the passage of arteries to nourish neural tissue?

Dura mater

Arachnoid mater

Pia mater

Answer 1

Pia mater

Explanation

The pia mater is the inner most (deepest) meningeal layer. It adheres to the contours of the brain, is impermeable to fluids and allows for the passage of arteries that will provide O2 and glucose to neural tissue. The dura mater is the tough outer layer that forms the dural reflections which separate structures of the brain and house the dural venous sinuses. The arachnoid mater is the intermediate layer. The barrier cells interface with the dura and the trabeculae extend down to the pia mater creating the subarchnoid space.

Question 2

The dura mater has a rich sensory innervation supplied by the trigeminal nerve and the dorsal roots of the C2 & C3 spinal nerves.

True or False

Answer 2

True

Question 3

The subarachnoid space contains which of the following? Select all that apply.

cerebrospinal fluid

neurons

astrocytes

arteries and veins

roots of cranial nerves

Answer 3

cerebrospinal fluid, arteries and veins, roots of cranial nerves

Explanation

The subarachoid space contains: CSF, arteries and veins, and the roots of the cranial nerves. Neurons (cell bodies located in the gray matter) and axons in the white matter are located in the substance of the brain; Astrocytes are glial cells located in the substance of the brain.

Question 4

Which of the following dural reflections separates the cerebral hemispheres?

Falx cerebelli

Tentorium cerebelli

Falx cerebri

Diaphragma sellae

Answer 4

Falx cerebri

Explanation

The falx cerebri is the largest of the dural reflections and it runs down the longitudinal fissure separating the right and left cerebral hemispheres. The falx cerebelli separates the cerebellar hemispheres; the tentorium cerebelli forms a roof or “tent” over the cerebellum separating the cerebrum & diencephalon from the cerebellum and brainstem; diaphragma sellae surrounds the stalk of the pituitary gland and forms a roof over the gland.

Question 5

Which dural reflection houses the superior sagittal sinus?

Falx cerebri

Falx cerebelli

Tentorium cerebelli

Diaphrgma sellae

Answer 5

Falx cerebri

Question 6

Which of the following herniation syndromes results when increased intracranial pressure causes the cingulate gyrus of one hemisphere to move under the falx cerebri entering the opposite hemisphere?

Subfalcine

Central

Upward cerebellar

Uncal

Answer 6

Subfalcine

Explanation

This describes a subfalcine (cingulate) herniation: a lesion in one cerebral hemisphere expands toward the midline, deforms the falx cerebri pushing the cingulate gyrus & the CC under the edge of the falx cerebri into the opposite hemisphere; Central and uncal herinations are descending transtentorial herniation syndromes causing brain structures to move from the supratentorial compartment into the infratentorial compartment; Upward cerebellar herniation results from increased intercranial pressure in the posterior cranial fossa that cause the cerebellum to move through the tentorium cerebelli into the supratentorial compartment.

Question 7

Which of the following herniation syndromes can cause compression of the posterior cerebral (PCA) or superior cerebellar arteries (SCA)?

Upward cerebellar

Subfalcine

Central

Tonsillar

Answer 7

Upward cerebellar

Explanation

An upward cerebellar herniation can cause compression of the PCA and the SCA – resulting in a PCA syndrome or an SCA syndrome. A subfalcine herniation can result in an anterior cerebral artery syndrome; a central herniation can result in damage to the midbrain causing a CN 3 palsy and contralateral hemiplegia; a tonsillar herniation can result in compression of the medulla.

Question 8

Which of the following best describes a subdural hematoma?

A collection of blood found between the periosteal layer of the dura and the skull.

A collection of blood found at the interface of the dura mater and the arachnoid mater.

A collection of blood found in the subarachnoid space.

Answer 8

A collection of blood found at the interface of the dura mater and the arachnoid mater.

Explanation

A subdural hematoma is a collection of blood found at the interface of the dura mater with the arachnoid mater. An epidural hematoma is a collection of blood found between the periosteal layer of the dura and the skull. A sub-arachnoid hemorrhage is bleeding in the subarachnoid space.