KMS - Lecture 8 & 9 - Cranial Meninges Flashcards
What are the layers, starting with cerebral cortex, of the meningeal layers?
Cortex/brain cells Pia mater Subarachnoid space with arachnoid trabeculae Arachnoid Dura layer
What tissue makes up pia mater?
Areolar CT
How are the tissues different between pia and arachnoid mater?
Arachnoid has somewhat more dense CT layer than pia - more elastic and collagen fibers
What forms the subarachnoid space? What are the contents?
Trabeculated deep surface of arachnoid mater
Contains CSF, cerebral aa and veins
What covers the brain? What dips into sulci?
Pia - covers, dips into sulci, invests vessels
Arachnoid - covers, doesn’t dip into sulci except for longitudinal fissure
Dura - covers, doesn’t dip into sulci - forms reflections
What forms cisterns?
Cisterns = areas of accumulated CSF
- formed by arachnoid mater and contours of the brain
What forms CSF (cerebrospinal fluid)?
Choroid plexus
- modified tuft of capillaries in the ventricles
How does CSF get into the sub-arachnoid space?
CSF flows through ventricles to 4th ventricle
- openings then communicate with sub-arachnoid space
Where is CSF reabsorbed? What structure is involved?
Into the superior sagittal sinus via arachnoid granulations
What tissue is the dura mater? What is it continuous with?
Dense fibrous CT layer enclosing brain
- continuous with spinal dura at foramen magnum
What is the periosteal layer of dura?
periosteum of cranial vault adherent to meningeal dura
What is the meningeal layer of dura? What do they form?
duplications of dura - prolonged between major portions of the brain
- form dural reflections
What meningeal layer eventually fuses with neural sheaths?
Dura mater - prolonged along cranial nerves
Name the 4 dural reflections.
Falx Cerebri
Tentorium Cerebelli
Falx Cerebelli
Diaphragma Sellae
What sinuses are in the falx cerebri?
Superior sagittal sinus
Inferior sagittal sinus
What are the attachments and shape of the falx cerebri?
Anterior- crista galli of ethmoid
- forms a sickle shape between hemispheres
Posterior - continuous with tentorium cerebelli at internal occipital protuberance
Follows contour of sagittal suture in its course
What forms a tent over the posterior cranial fossa? What separates cerebellum from posterior cranial hemispheres?
Tentorium cerebelli
What sinuses does the tentorium cerebelli enclose?
Transverse sinuses
Superior petrosal sinuses
Where does the tentorium cerebelli attach?
Anterior - ant. and post. clinoid processes of sphenoid bone
Periphery - occipital bone at grooves for transverse sinus
What is the tentorial notch?
Free anterior concave margin of tentorium which wraps around midbrain
Which dural reflection can kill you? How?
Tentorial notch on tentorium cerebelli
- can transect midbrain during rapid deceleration or loss of CSF
What is the span of the falx cerebelli?
Extension of dura
Runs between cerebellar hemispheres
Runs from tentorium above to occipital crest below
What does the falx cerebelli contain?
Occipital sinus
What is the diaphragma sellae? What does it cover?
Specialized portion of dura
Forms roof over hypophyseal fossa
