The cavernous sinus within the human head is one of the

dural venous sinuses The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous sinuses (channels) found between the periosteal and meningeal layers of dura mater in the brain. They receive blood from the cerebral veins, ...

creating a cavity called the lateral sellar compartment bordered by the

temporal bone The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ...

of the

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

and the

sphenoid bone The sphenoid bone is an unpaired bone of the neurocranium. It is situated in the middle of the skull towards the front, in front of the basilar part of occipital bone, basilar part of the occipital bone. The sphenoid bone is one of the seven bon ...

, lateral to the sella turcica.

Structure

The cavernous sinus is one of the dural venous sinuses of the head. It is a network of veins that sit in a Sinus (anatomy), cavity. It sits on both sides of the sphenoidal bone and pituitary gland, approximately 1 × 2 cm in size in an adult. The internal carotid artery#C4: Cavernous segment, carotid siphon of the internal carotid artery, and cranial nerves III, IV, V (branches V₁ and V₂) and VI all pass through this blood filled space. Both sides of cavernous sinus are connected to each other via intercavernous sinuses. The cavernous sinus lies in between the inner and outer layers of dura mater.

Nearby structures

* Above: optic tract, optic chiasma, internal carotid artery. * Inferiorly: foramen lacerum, and the junction of the body and greater wing of sphenoid bone. * Medially: Hypophysis cerebri, pituitary gland (hypophysis cerebri), and sphenoidal air sinus. * Laterally: temporal lobe with uncus. * Anteriorly: superior orbital fissure, and the apex of the orbit. * Posteriorly: apex of petrous temporal bone.

Venous connections

The cavernous sinus receives blood from: * Superior ophthalmic vein, Superior and inferior ophthalmic veins * Sphenoparietal sinus * Superficial middle cerebral veins * Inferior cerebral veins Blood leaves the sinus via Superior petrosal sinus, superior and inferior petrosal sinuses as well as via the emissary veins through the foramina of the skull (mostly through Foramen ovale (skull), foramen ovale). There are also connections with the pterygoid plexus of veins via inferior ophthalmic vein, deep facial vein and emissary veins.

Apart from the blood which passes through a venous sinus, several anatomical structures, including some cranial nerves and their branches, also pass through the sinus. Structures within the outer (lateral) wall of the compartment from Anatomical terms of location, superior to inferior: *Oculomotor nerve *Trochlear nerve *Ophthalmic nerve, Ophthalmic and Maxillary nerve, maxillary branches of the trigeminal nerve Structures passing through the midline (medial) wall: *Abducens nerve *Internal carotid artery accompanied by the internal carotid plexus These nerves, with the exception of CN V₂, pass through the cavernous sinus to enter the orbital apex through the superior orbital fissure. The maxillary nerve, division V₂ of the trigeminal nerve travels through the lower portion of the sinus and exits via the foramen rotundum. The maxillary branch passes external to, but immediately adjacent to, the lateral wall of the sinus. The optic nerve lies just above and outside the cavernous sinus, superior and lateral to the pituitary gland on each side, and enters the orbital apex via the optic canal.

Function

Venous drainage

As a venous sinus, the cavernous sinus receives blood from the Superior ophthalmic vein, superior and inferior ophthalmic veins and from superficial cortical veins, and is connected to the basilar plexus of veins posteriorly. The cavernous sinus drains by two larger channels, the superior and inferior petrosal sinuses, ultimately into the internal jugular vein via the sigmoid sinus, also draining with emissary vein to pterygoid plexus.

Clinical significance

It is the only anatomic location in the body in which an artery travels completely through a venous structure. If the internal carotid artery ruptures within the cavernous sinus, an ''arteriovenous fistula'' is created (more specifically, a carotid-cavernous fistula). Lesions affecting the cavernous sinus may affect isolated nerves or all the nerves traversing through it. The pituitary gland lies between the two paired cavernous sinuses. An abnormally growing pituitary adenoma, sitting on the bony sella turcica, will expand in the direction of least resistance and eventually invade the cavernous sinus. Cavernous sinus syndrome may result from mass effect of these tumors and cause Ophthalmoparesis, ophthalmoplegia (from compression of the oculomotor nerve, trochlear nerve, and abducens nerve), ophthalmic sensory loss (from compression of the ophthalmic nerve), and maxillary sensory loss (from compression of the maxillary nerve). A complete lesion of the cavernous sinus disrupts CN III, IV, and VI, causing total ophthalmoplegia, usually accompanied by a fixed, dilated pupil. Involvement of CN V (V₁ and variable involvement of V₂) causes sensory loss in these divisions of the trigeminal nerve. Horner's syndrome can also occur due to involvement of the carotid ocular sympathetics, but may be difficult to appreciate in the setting of a complete third nerve injury.Blumenfeld, H, Neuroanatomy through clinical cases. Sinauer Associates, Inc., 2002. Because of its connections with the facial vein via the superior ophthalmic vein, it is possible to get infections in the cavernous sinus from an external facial injury within the danger area of the face. In patients with thrombophlebitis of the facial vein, pieces of the clot may break off and enter the cavernous sinus, forming a cavernous sinus thrombosis. From there the infection may spread to the

. Infections may also be introduced by facial lacerations and by bursting pimples in the areas drained by the facial vein.Kumar, P. & Clark, M. Clinical Medicine, 6th ed. London: W.B. Saunders; 2005. Potential causes of cavernous sinus syndrome include metastatic tumors, direct extension of nasopharynx cancer, nasopharyngeal tumours, meningioma, pituitary tumors or pituitary apoplexy, aneurysms of the intracavernous carotid artery, carotid-cavernous fistula, bacterial infection causing cavernous sinus thrombosis, Cavernous sinus thrombosis, aseptic cavernous sinus thrombosis, idiopathic granulomatous disease (Tolosa–Hunt syndrome), and fungal infections. Cavernous sinus syndrome is a medical emergency, requiring prompt medical attention, diagnosis, and treatment.

References

External links

* * "Venous dural sinuses." * * * {{Authority control Veins of the head and neck Medical mnemonics