Dura Mater and Dural Venous Sinuses Flashcards
What are the meninges of the brain?
membrane coverings of the brain and spinal cord
Name the 3 meninges that cover the brain (from outward to inward)?
- Dura mater - thickest
> pachymenix - Arachnoid mater
- Pia mater
> Arachnoid + pia = leptomeninges
Describe the Dura mater?
- Thick, tough collagenous membrane
- Adheres to inner surface of the skull
What are the 2 layers of the dura mater?
- Endosteal layer – acts as periosteum
> continuous with the outer periosteum of the outer cranium - Meningeal layer – meningeal dura
> continuous with spinal cord dura mater
The 2 layers of the dura separate from each other at numerous locations to form which 2 unique types of structures?
- dural partitions
> which project inward and incompletely separate parts of the brain - intracranial venous structures
What are the spaces of the dura mater?
- Epidural space – potential space between dura and calvaria
- Subdural space – potential space in the innermost dural layer: near the dural-arachnoid interface
Describe the dura mater at the foramen magnum?
- Periosteal dura layer is continuous with the outer periosteum of the outer cranium
- Meningeal dura layer is continuous with spinal cord dura mater
What are dural septa?
folds of the inner dural layer into the cranial cavity
> Dural septa partially separate different intracranial compartment
What are the 4 principal dural reflections?
- Falx cerebri – between two cerebral hemispheres
- Tentorium cerebelli – between cerebrum and cerebellum
- Falx cerebelli – small reflection that separates the two cerebellar hemispheres
- Diaphragma sellae – small reflection that covers the pituitary fossa pereforated by the infundibular stalk of the gland
Describe the falx cerebri?
Sickle shaped double layer of dura mater, lying between cerebral hemispheres
Where is the falx cerebri attached?
- anteriorly > crista galli
- posteriorly > tentorium cerebelli at internal occipital protuberance
Note: free edge parallels the corpus callosum
What are the structures contained in the falx cerebri?
- free inferior concave border > contains inferior sagittal sinus
- Upper convex margin > encloses superior sagittal sinus
Describe the falx cerebelli?
Small sickle shaped projection between the cerebellar hemispheres
> Attached to posterior parts of tentorium cerebelli
What is the corpus callosum?
a large bundle of more than 200 million myelinated nerve fibers that connect 2 brain hemispheres permitting communication between the right and the left side of the brain
> free edge of falx cerebri parrallels the corpus callosum
Describe the tentorium cerebelli?
Separates the superior part of the cerebellum and the occipital lobe of the cerebrum
The tentorium cerebelli separates the posterior fossa into?
- Superotentorial compartment - contains cerebrum
- Infratentorial compartment (posterior fossa) - contains brain stem and cerebellum
Describe the attachment points of the tentorium cerebelli?
- Posteriorly the tentorium attaches to the occipital bone
- The free edge incircles the midbrain and is called tentorial notch or tentorial incisure (clinically important)
What are the structures within the tentorium cerebelli?
External convex border encloses:
> posteriorly = transverse sinus
> anteriorly = superior petrosal sinus
Describe the diaphragma sellae?
- Circular, horizontal fold of dura mater that forms the roof of sella turcica, covering the pituitary gland
- Has a central aperture for the hypophysial stalk
Describe the venous drainage of the cranial cavity?
> Dura mater contains venous sinuses that drain the brain in edges of dural reflections
In edges of reflection the two layers separate to form channels called dural venous sinus
Cerebral veins empty into dural venous sinuses