Meninges and Ventricles Flashcards
What do the meninges refer to?
the membranous coverings of the brain and spinal cord
How many layers of meninges are there? What are they called?
3 layers:
- Dura mater (outermost)
- Arachnoid mater (middle)
- Pia mater (innermost)

What are the 2 major functions of the meninges?
- Provide a supportive framework for the cerebral and cranial vasculature.
- Acting with cerebrospinal fluid to protect the CNS from mechanical damage.
How are the meninges often involved in cerebral pathology?
a common site of infection (meningitis), and intracranial bleeds.
Diagram of the meninges around the brain

Which layer of the meninges lies directly underneath the bones of the skull and vertebral column?
Dura mater
Describe the dura mater
It is thick, tough and inextensible (protective)
Describe arachnoid mater
Thin, delicate layer, spider’s web-like, vascular
Describe the pia mater
Microscopically thin, follows gyri and sulci (tightly adhered to surface of brain)

Where does the dura mater receive its blood supply from?
primarily from the middle meningeal artery and vein.
Within the cranial cavity, the dura contains two connective tissue sheets. What are these called?
- Periosteal layer
- Meningeal layer

What does the periosteal dura mater layer line?
The inner surface of the bones of the cranium (tightly adhered to)

What does the meningeal dura mater layer line?
Deep to the periosteal layer inside the cranial cavity - tightly adhered to the arachnoid mater. (It is the only layer present in the vertebral column)
Where is the only space in the layers of the meninges?
Below the arachnoid mater –> subarachnoid space

What is found in the subarachnoid space?
Cerebrospinal fluid
Function of cerebrospinal fluid?
acts to cushion the brain
Only at specific areas, the inner dural layer separates from the outer layer and protrude into the cranial cavity. What does this form?
Forming double-layered dural folds (also called partitions or septae)

Dural infoldings diagram
These dural infoldings partition the brain, and divide the cranial cavity into several compartments.

How many dural infoldings are there? What are they called?
3 folds:
- Falx cerebri
- Tentorium cerebelli
- Falx cerebelli

Where is the falx cerebri located?
Between the two cerebral hemispheres (forms a sickle shape from front to back)

Where is the tentorium cerebelli located?
Separates the cerebral hemispheres from the cerebellum below (tent over the cerebellum) –> divides the cranial cavity into supratentorial and infratentorial compartments

Where is the falx cerebelli located?
It is a small infolding of the dura in the sagittal plane over the floor of the posterior cranial fossa. Separates the two cerebellar hemispheres

What are the attachments of the falx cerebri?
Anterior: crista galli of ethmoid bone
Posterior: inner surface of occipital bone (internal occipital protuberance)

Superior view of the floor of the cranial cavity

















































