Cavernous sinus

Vein: Cavernous sinus
Cavernous sinus (center, labeled "SIN. CAVERN.")
The sinuses at the base of the skull. Cavernous sinus labeled in red
Latin	sinus cavernosus
Gray's	subject #171 658
Source	middle cerebral vein, sphenoparietal sinus, superior ophthalmic vein
Drains to	inferior petrosal sinus, superior petrosal sinus
MeSH	Cranial+Sinuses

The cavernous sinus (or lateral sellar compartment), within the human head, is a large collection of thin-walled veins creating a cavity bordered by the temporal bone of the skull and the sphenoid bone, lateral to the sella turcica.

Contents

The sinus may be joined by several anastomoses across the midline. The cavernous sinus receives the ophthalmic vein through the superior orbital fissure and is connected to the basilar plexus of veins posteriorly. The internal carotid artery, and cranial nerve III, IV, V, and VI all pass through this blood filled space. Infection from the face may reach the cavernous sinus through its many anastomotic connections, with severe consequences. The cavernous sinus drains by two channels, the superior and inferior petrosal sinuses.

Each cavernous sinus (one for each hemisphere of the brain) contains the following:

• vertically, from superior to inferior
  • oculomotor nerve (CN III)
  • trochlear nerve (CN IV)
  • ophthalmic nerve, the V₁ branch of the trigeminal nerve (CN V)
  • maxillary nerve, the V₂ branch of CN V

• horizontally
  • internal carotid artery (and sympathetic plexus). See also cavernous part of internal carotid artery.
  • abducens nerve (CN VI)

One mnemonic for remembering the contents is "OTOM CAT"^[1]

Venous connections

It receives tributaries from:

• Superior and inferior ophthalmic veins
• Sphenoparietal sinus
• Superficial middle cerebral veins

The veins of exit are to the superior and inferior petrosal sinuses as well as via the emissary veins through the foramina of the skull (mostly through foramen ovale). There are also connections with the pterygoid plexus of veins via inferior ophthalmic vein, deep facial vein and emissary veins.

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).

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 compress the cavernous sinus. Cavernous sinus syndrome may result from mass effect of these tumors and cause 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).

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. This is especially likely as the facial vein has no valves, allowing blood to pass in both directions. In patients with thrombophlebitis of the facial vein, pieces of the clot may break off and enter the cavernous sinus, and from there the infection may spread to the dural venous sinuses. Infections may also be introduced by facial lacerations and by bursting pimples in the areas drained by the facial vein.^[2]

Additional images

Oblique section through the cavernous sinus.

Veins of orbit.

Pathways in the Ciliary Ganglion.

Human brain dura mater (reflections)

See also

• Dural venous sinuses

References

External links

• MedEd at Loyola grossanatomy/h_n/cn/dvs/dvs3.htm
• SUNY Figs 28:03-06 - "Venous dural sinuses."
• MeSH Cavernous+Sinus
• lesson2 at The Anatomy Lesson by Wesley Norman (Georgetown University)
• Atlas of anatomy at UMich n3a8p1
• Cavernous+sinus at eMedicine Dictionary

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