The Cavernous Venous Sinus

This is clinically very important on account of the following:

  • It's numerous extracranial and intracranial communications.
  • The structures contained within it and its walls.
  • Its proximity to the pituitary gland.

  • It is found on each side of the sella turcica and the sphenoid body.
  • Extending from the superior orbital fissure to the apex of the petrous temporal bone.
  • The cavum trigerminale is located lateral to it.


Medially: Pituitary gland(1) and sphenoidal air cells(2).

Superiorly: Temporal lobe of the brain(3).

Laterally: Trigerminal ganglion and nerve.

Anteriorly: The contents of the superior orbital fissure and ................the optic nerve.

Posteriorly: Petrous temporal bone.

Within: Lateral wall - Oculomotor, trochlear, ophthalmic and ...........maxillary nerves.

In it: Carotid siphon with its associated sympathetic plexus, ........the abducens nerve and venous blood.


Inter-cranial communications
  • Superficial middle cerebral vein.
  • Intercavernous sinuses connect the two sides.
  • Sphenoparietal sinus.
  • Superior petrosal sinus connects it to the transverse sinus or sigmoid.
  • Inferior petrosal sinuses connect it to the internal jugular vein.

Extracranial communications
  • Superior and inferior ophthalmic veins.
  • The pterygoid venous plexus Via emissary veins.
  • The pharyngeal venous plexus.
Note that the facial vein communicates through the ophthalmic veins and the pterygoid plexus.

Clinical correlates on the cavernous venous sinus
Spread of infections

Danger area of the face

Infections from here spread to cavernous sinus via opthalmic veins




Cavernous sinus thrombosis

A common effect of infection of in a venous sinus is thrombosis. The risk is higher in the cavernous sinus due to the slow movement of blood. The effects are usually:

  • Back-flow into the connecting veins, for example ophthalmic veins leading to exopthalmos and engorged conjuctiva (chemosis)
  • Compression of the nerves to the extraocular muscles leading to ophthalmoplegia and impaired sensation in the area of supply of Cranial V1 and V2.

Arteriovenous fistula

This may be produced by fractures of the bases of the skull, in which the internal carotid artery tears within the cavernous sinus. Arterial blood rushes in to the sinus, enlarging it and forcing blood out of it through the communicating veins. This causes exophthalmos and chemosis on the side of the injury. In these circumstances, the bulging eye pulses in synchrony with the radial (or any other) pulse. This condition is called pulsatile exophthalmos.



Infections spreading to the sinuses may affect the pituitary and the many cavernous sinus communications may provide alternative routes for spread of malignancies.