The dura mater has two layers namely an outer endosteal layer adherent to the inner surface of the cranium, and an inner meningeal layer . At various sites, these layers separate and form large dural venous sinuses .

1. Falx cerebri
2. Falx cerebelli
3. Tentorium cerebelli
4. Diaghragma sella
5. Cavum trigeminale

Tentorium cerebelli divides into

1. Supratentorial [S.T]
2. Infratentorial [I.T]

Supratentorial compartment divided by falx cerebri into right and left.

Diaghragma sella covers hypophyseal compartment.

Cavum trigeminale covers trigeminal ganglion.

The infratentorial is divided by falx cerebelli into the left and right.