Cavernous sinus

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Cavernous sinus

The cavernous sinus is a large collection of thin-walled veins creating a cavity bordered by the temporal bone of the skull and the sphenoid bone. It is one of the dural venous sinuses and is located on either side of the sella turcica, a saddle-shaped depression in the sphenoid bone where the pituitary gland resides.

Anatomy

The cavernous sinus is a paired structure, meaning there is one on each side of the sella turcica. It extends from the superior orbital fissure anteriorly to the apex of the petrous part of the temporal bone posteriorly. The sinus is bordered by the meningeal layer of the dura mater and contains several important structures.

Contents

The cavernous sinus contains the following structures:

• The internal carotid artery and its accompanying sympathetic plexus.
• The oculomotor nerve (CN III).
• The trochlear nerve (CN IV).
• The ophthalmic nerve (V1) and the maxillary nerve (V2), both branches of the trigeminal nerve (CN V).
• The abducens nerve (CN VI).

Connections

The cavernous sinus has several important venous connections:

• The superior ophthalmic vein and the inferior ophthalmic vein drain into the cavernous sinus.
• The sphenoparietal sinus also drains into the cavernous sinus.
• The cavernous sinus drains posteriorly into the superior petrosal sinus and the inferior petrosal sinus.

Function

The primary function of the cavernous sinus is to drain venous blood from the brain and the orbit. It also plays a role in the regulation of intracranial pressure and the cooling of arterial blood before it reaches the brain.

Clinical Significance

The cavernous sinus is clinically significant due to its contents and connections. Conditions affecting the cavernous sinus include:

• Cavernous sinus thrombosis: A blood clot within the cavernous sinus, often caused by infection.
• Carotid-cavernous fistula: An abnormal connection between the internal carotid artery and the cavernous sinus.
• Tolosa-Hunt syndrome: A rare disorder causing painful ophthalmoplegia due to inflammation of the cavernous sinus.

See Also

• Dural venous sinuses
• Sella turcica
• Pituitary gland
• Internal carotid artery
• Oculomotor nerve
• Trochlear nerve
• Trigeminal nerve
• Abducens nerve