Vascular Lesions of the Orbit and Face by Michael T. Yen

Author:Michael T. Yen
Language: eng
Format: epub
Publisher: Springer International Publishing, Cham

7.3.2 Anatomy of the Cavernous Sinus

The cavernous sinus is located at the base of the skull, closely associated with the osseous structures of the sphenoid bone and the sella turcica. The foramen rotundum, foramen ovale, and foramen lacerum are immediately adjacent. The cavernous sinus is bordered by two layers of dura mater, with a periosteal layer forming the floor and medial wall and dural layer forming the roof. Cranial nerves III, IV, and V1, and V2 are embedded in the lateral wall of the cavernous sinus. The internal carotid artery passes through the cavernous sinus, both in horizontal and vertical planes. According to the commonly accepted Bouthillier system (1996), the cavernous carotid is the fourth segment of the internal carotid artery. Within the cavernous segments, meningeal branches include the inferior hypophyseal artery and inferior lateral trunk. These branches may be involved in indirect fistula.

The cavernous sinus is part of the family of dural venous sinuses. They are not classically veins, as they are endothelial tubes, lined with firm connective tissue, and do not contain the valves which are normally seen in veins. The cavernous sinus forms a central collection zone for blood draining from the middle cerebral veins, meningeal veins, the sphenoparietal sinus, and the ophthalmic veins. The sinus is very seldom a single large space. It was Winslow in 1732 that originally termed the sinus as “cavernous” because of the caverns he found formed by multiple fibers and connective tissue septae. In 80 % of patients, an unbroken channel can be found connecting the two sides of the cavernous sinus called the circular sinus.

After receiving blood from the brain and orbits, the cavernous sinus typically drains toward the transverse sinuses and the internal jugular veins. The cavernous sinus connects to the transverse sinus through the superior petrosal sinus and the jugular vein primarily through the inferior petrosal sinus and basilar venous plexus. Another important route for cavernous sinus drainage is via the pterygoid venous plexus which then drains to the maxillary and retromandibular vein into either the external or internal jugular vein (Fig. 7.2).

Fig. 7.2The interconnected nature of the cavernous sinus can be appreciated on this artist rendition of the veins and sinuses viewed from above, superimposed on the skull base. The main structures related to catheterization of the cavernous sinus are labeled. The inferior petrosal sinus is the most common route for embolization of the cavernous sinus with the superior petrosal the second most commonly utilized. 1 Superior Ophthalmic Vein, 2 Sphenoparietal Sinus, 3 Intercavernous Sinus, 4 Cavernous Sinus, 5 Superior Petrosal Sinus, 6 Inferior Petrosal Sinus, 7 Basilar Venous Plexus, 8 Sigmoid Sinus (Bendorf 2010)

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