Meninges & Meningeal spaces

Flashcard maker : Maddison Bailey
meninges
are three layers of protective tissue called the dura mater, arachnoid mater, and pia mater that surround the neuraxis
skin of scalp
periosteum
epidural space
-space between the dura mater and the periosteum
-always exists around spinal cord but usually NOT around the brain because the dura mater fuses with the bony plates of the skull
dura mater
most superficial layer and toughest of the three meningeal layers, composed of two layers
periosteal dura mater
upper layer of the dura mater
-fuses to the inner surface of the bony plates of the cranium
-this layer does NOT descend with the spinal cord and therefore is NOT fused to the vertebrae
Meningeal dura mater
lower layer of the dura mater
-found around both the brain and spinal cord
superior sagittal sinuses
formed where the periosteal and meningeal layers separate to form a channel
venous blood
collects in and travels through dural sinuses absorbing CSF by osmosis.
-The osmotic pressure of the venous blood (due to presence of proteins) is greater than the OP of the CSH
arachnoid mater
the middle of the three meningeal layers
thin, delicate layer resembling cobwebs just under the dura mater and extending towards the pia mater
arachnoid villus
knob-like projections of the arachnoid mater that extend through the dura mater into the superior sagittal sinus

-CSF is absorbed through these into the venous blood by osmosis
-aka (arachnoid granulations)

pia mater
the deepest of the three meningeal layers

-it is bound tightly to the surface of the brain and cord

subarachnoid space
space between the arachnoid mater and pia mater
-always exists around both the brain and spinal cord
filled w/ CSF
-extends all the way to the level of S2
-a sample of CSF is withdrawn from this space in the lumbar region to test for meningitis during a spinal tap
subdural space
space between the dura mater and the arachnoid mater

-filled w/ 140-150 ml of CSF
-always exsist around the brain but usually not around the spinal cord

subdural hematoma
collection/clot of blood between the surface of the brain and dura mater
falx cerebri
is a large, crescent-shaped fold of meningeal layer of dura mater that descends vertically in the longitudinal fissure between the cerebral hemispheres
falx cerebelli
is a small infolding of the dura in the sagittal plane over the floor of the posterior cranial fossa. It partially separates the two cerebellar hemispheres
tentorium cerebelli
crista galli
pituitary gland
cerebellum
the part of the brain at the back of the skull in vertebrates. Its function is to coordinate and regulate muscular activity.
superior sagittal sinus
is the largest dural venous sinus
straight sinus
is one of the main dural venous sinuses

-found at the junction between the falx cerebri and the tentorium cerebelli and is triangular in cross section

transverse sinus
is one of the dural venous sinuses

-drains the superior sagittal sinus the occipital sinus and the straight sinus, and empties into the sigmoid sinus which in turn reaches the jugular bulb.

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