Trigeminal or Meckel's cave is present in relation to:
Meninges of Brain
i) Brain is protected by

Bony covering of the cranium
Three membranous coverings (Meninges)

ii) The three meninges are

Outer duramater
Middle arachnoid mater
Inner piamater

iii) The dura mater is outermost and thickest of all meninges. It encloses cranial venous sinuses and has a distinct blood supply and nerve supply.
iv) The duramater has two layers - an outer endosteal layer and an inner meningeal layer.
v) The outer endosteal layer forms the endosteum of skull.
vi) The meningeal layer is folded and form partitions which divide cranial cavity into compartments. The folds are

falx cerebri
falx cerebella
Tentorium cerebella
Diaphragma Sella.

vii) FALX CEREBRI
It is a large sickle shaped fold of duramater occupying the median longitudinal fissure between two cerebral hemispheres.
The superior sagittal sinus, inferior sagittal sinus and the straight sinus are closely related to falx cerebri.
viii) FALX CEREBELLI
It is present in the posterior cerebellar notch.
ix) TENTORIUM CEREBELLI
It forms the roof of the posterior fossa and separates the cerebellum from occipital lobes of the cerebrum. The trigeminal or meckel's cave is present in relation to tentorium cerebelli.
x) DIAPHRAGMA SELLAE
It is a small circular, horizontal fold of duramater forming the roof of the hypophyseal fossa.
The diaphragm has a central aperture through which the stalk of hypophysis cerebri passes.
Falx cerebri
Falx cerebelli
Tentorium cerebelli
Diaphragma sellae