Dural Venous Sinuses

• Venous channels situated between inner & outer layers of Dura mater

• Drain the venous blood of the brain & bones of the skull.

• Transmit the venous blood to the internal jugular vein.

• Communicates with the internal vertebral venous plexus through the foramen magnum

• Also communicates with the scalp veins through the emissary veins

• Valveless

The Dural sinuses maybe divided into 2 groups

• 1- single: Superior saggital , Inferior saggital & Occipital

• 2- Paired: Spheno-parietal , Cavernous , Superior petrosal , Inferior petrosal & Sigmoid.

1- Superior sagittal sinus Attachments.

• Begins in front at the frontal crest & ends behind at the internal occipital protuberance

• The superior sagittal sinus receives the following :

• 1- Superior cerebral veins • 2- dipolic veins • 3- Emissary veins• 4- arachnoid granulation • 5- meningeal veins

2 – Inferior sagittal sinus• It occupies the posterior 1/2 or 2/3 of the lower

free border of falx cerebri.• It ends posteriorly by joining the straight sinus • It receives cerebral veins from the medial surface

of the cerebral hemisphere

3- Straight sinus• It lies at the junction of the falx cerebri and

tentorium cerebelli It receives : • 1- inferior sagital sinus • 2- great cerebral vein • It ends at internal occipital protuberance by

becoming the left transverse sinus

4- Transverse sinus• Paired sinus• It extends horizontally in the attached border of

tentorium cereblli.• The right sinus receive the superior sagittal sinus

however ,the left sinus receive the inferior sagittal sinus • Each sinus end by becoming continuous with sigmoid

sinus • Transverse sinus receive the following tributaries :• 1- Superior petrosal sinus • 2- cerebellar veins • 3- Occipital diploic vein.

5- occipital sinus

• It is the smallest dural sinus & is situated in the attached margin of the falx cerebelli

• It continuates with the internal vertebral plexus

6- Spheno-parietal sinus• paired sinus• It lies on the edge of the lesser wing of sphenoid

7- superior petrosal sinus• It is a paired sinus situated on the upper border of

the petrous bone• It lies at the attachment border of tentorium

cerebelli • It continues with cavernous sinus anteriorly & with

transverse sinus posteriorly.

8- Inferior petrosal sinus

• It is a paired sinus situated between the petrous bone & basilar part of occipital bone

• It communicates with cavernous sinus anterior & with superior bulb of internal jugular vein posterior

9- Cavernous sinus• Position: it lies on the side of the body of sphenoid• Relation:

A- Medially • Sphenoid air sinus • Pituitary gland B- Laterally • Trigeminal ganglion • Uncus of temporal lobe C- Nerves in its lateral wall• 3RD cranial nerve • 4th cranial nerve • Ophthalmic division of 5th cranial nerve maxillary division of 5th cranial nerve D- Structures within its cavity• Internal carotid artery • Abducent nerve

• Tributaries of cavernous sinus : A- Anteriorly • 1- Ophthalmic vein • 2- Spheno-parietal sinus B- Posteriorly • Superior petrosal sinus• Inferior petrosal sinus C- Medially • Anterior & posterior intercavernous sinuses

D- Superior • Superficial middle cerebral vein • Veins from inferior surface of brain

E- Inferior • Emissary vein through the carotid canal which

connects the sinus with internal jugular vein • Emissary vein through the foramen ovale which

connects the sinus with pterygoid venous plexus

• The cavernous sinus communicates with the veins of the face through 2 routes :

• Superior ophthalmic veins, • Deep facial vein,• pterygoid plexus of veins & • emissary vein through the foramen Ovale.

10- Sigmoid sinus

• It is wide S- shaped sinus which begins at the lateral & of transverse sinus .

• The sinus ends by passing through the jugular foramen where it becomes continues with internal jugular vein

It has the following tributaries

• Posterior condylar emissary vein • Mastoid emissary vein

• Applied Anatomy :

• Cavernous Sinus Thrombosis.• Meningioma.