Venous Sinuses of Cranial Cavity

Within the cranial cavity, between the two layers of dura mater at certain locations, there are blood-filled, endothelium-lined spaces called venous sinuses of cranial cavity. There walls are thick and composed of fibrous tissue and they lack muscular tissue in their walls.

Superior sagittal sinus:

It lies in the upper fixed border of the falx cerebri and runs towards the occipital bone where it becomes continuous with the right transverse sinus. It receives the superior cerebral veins.

The superior sagittal sinus communicates on each side with the venous lacunae, into which numerous arachnoid villi and granulations project.

Inferior sagittal sinus:

It lies in the lower free margin of the falx cerebri. It runs backward and joins the great cerebral vein to form the straight sinus. It receives cerebral veins from the medial surface of the cerebral hemisphere.

Straight sinus:

It lies at the junction of the tentorium cerebelli and the falx cerebri. As stated above, it is formed by the union of the inferior sagittal sinus and the great cerebral vein. It eventually drains into the left transverse sinus.

Occipital sinus:

It lies in the attached margin of the falx cerebelli. It communicates with the vertebral veins through the foramen magnum and the transverse sinuses.

Right and Left transverse sinuses:

The left transverse sinus is a continuation of the straight sinus while the right transverse sinus is the continuation of the superior sagittal sinus. Each sinus lies in the lateral attached margin of the tentorium cerebelli and end by becoming the sigmoid sinus on respective side.

Sigmoid sinuses:

They are a direct continuation of transverse sinus of respective side. Sigmoid sinus of each side leaves the skull through the jugular foramen of that side and becomes respective internal jugular vein.

Cavernous sinuses:

Each cavernous sinus lies on the lateral side of the body of the sphenoid bone. It drains posteriorly into the transverse sinus through the superior petrosal sinus. Intercavernous sinuses connect the two cavernous sinuses through the sella turcica.

Cavernous sinuses receive the inferior ophthalmic vein and the central vein of the retina from their respective side.