Post on 10-Apr-2015
MeningesMeninges
The arachnoid does not follow the contours of the brain as the pia mater does.But stretches across any irregularities on the brain.This leads to the formation of pools of subarachnoid space, especially around the brain stem.These extensions are called sub arachnoid cisterns.
The largest of them is called
cerebellomedullary cistern(cisterna magna).
This is used to tap the CSF.
and this process is called the cisternal puncture.
Others cisterns are the
interpeduncular cistern,
pontine cistern,
supracallosalcistern,
cisterna ambience etc.
Cisterna magna
Pontine cistern
P C
M
Cisterna ambiens
Dural foldsDural folds
The cranial dura has two layers(endosteal and meningeal)The meningeal layer forms two sickle shaped folds called falx cerebri and falx cerebelli and two tents; Tentorium cerebelli and diaphragma sellae.
Falx cerebri
Tentorium cerebelliFalx(L. sickle)
Between the two layers of Dura There are venous spaces
called the Dural venous sinuses.
Tentorium cerebelliTentorium cerebelli
Separates the Separates the occipital lobes from occipital lobes from the cerebellum.the cerebellum.
Along its attached Along its attached margins are the margins are the transverse sinuses.transverse sinuses.
To show the tentorial notch and free margins of tentorium
Falx cerebelliFalx cerebelli
Present between the Present between the two cerebellar two cerebellar hemispheres.hemispheres.
Daiphragma sellaeDaiphragma sellae
Covers the pituitary Covers the pituitary gland in the sella gland in the sella turcica. Pierced by turcica. Pierced by the infundibulum the infundibulum (pituitary stalk).(pituitary stalk).
Showing calcification ofFalx cerebri