Cavernous sinus
Encyclopedia
The cavernous sinus within the human head, is a large collection of thin-walled vein
s creating a cavity bordered by the temporal bone
of the skull
and the sphenoid bone
, lateral to the sella turcica
.
Each cavernous sinus (one for each hemisphere of the brain) contains the following:
Unlike the nerves listed above, the abducens nerve (CN VI) does not run within the lateral wall of the cavernous sinus; rather, it runs through the middle of the sinus alongside the internal carotid artery
.
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 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.
One mnemonic for remembering the contents is "OTOM CAT"
The veins of exit are to the superior and inferior petrosal sinus
es 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.
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 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). 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.
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. 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, forming a cavernous sinus thrombosis
. 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.
Potential causes of cavernous sinus syndrome include metastatic tumors, direct extension of nasopharyngeal tumors, meningioma, pituitary tumors or pituitary apoplexy, aneurysms of the intracavernous carotid artery, cavernous-carotid arteriovenous fistula, bacterial infection causing cavernous sinus thrombosis, aseptic thrombosis, idiopathic granulomatous disease (Tolosa-Hunt syndrome
), and fungal infections. Cavernous sinus syndrome is a medical emergency, requiring prompt medical attention, diagnosis, and treatment.
Vein
In the circulatory system, veins are blood vessels that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are the pulmonary and umbilical veins, both of which carry oxygenated blood to the heart...
s creating a cavity bordered by the temporal bone
Temporal bone
The temporal bones are situated at the sides and base of the skull, and lateral to the temporal lobes of the cerebrum.The temporal bone supports that part of the face known as the temple.-Parts:The temporal bone consists of four parts:* Squama temporalis...
of the skull
Human skull
The human skull is a bony structure, skeleton, that is in the human head and which supports the structures of the face and forms a cavity for the brain.In humans, the adult skull is normally made up of 22 bones...
and the sphenoid bone
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
, lateral to the sella turcica
Sella turcica
-External links:*...
.
Contents
The sinus may be joined by several anastomoses across the midline. The cavernous sinus receives blood via the ophthalmic vein through the superior orbital fissure and from superficial cortical veins, and is connected to the basilar plexus of veins posteriorly. The internal carotid artery (carotid siphon), and cranial nerves III, IV, V (branches V1 and V2) 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, ultimately into the internal jugular vein.Each cavernous sinus (one for each hemisphere of the brain) contains the following:
- vertically, from superior to inferior (within the lateral wall of the sinus)
- oculomotor nerveOculomotor nerveThe oculomotor nerve is the 3rd of 12 paired cranial nerves. It enters the orbit via the superior orbital fissure and controls most of the eye's movements, including constriction of the pupil and maintaining an open eyelid by innervating the Levator palpebrae superiors muscle. The optic nerve is...
(CN III) - trochlear nerveTrochlear nerveThe trochlear nerve is a motor nerve that innervates a single muscle: the superior oblique muscle of the eye....
(CN IV) - ophthalmic nerveOphthalmic nerveThe ophthalmic nerve is one of the three branches of the trigeminal nerve, the fifth cranial nerve. The ophthalmic nerve carries only sensory fibers.-Branches:*Nasociliary nerve**sensory root of ciliary ganglion**posterior ethmoidal nerve...
, the V1 branch of the trigeminal nerveTrigeminal nerveThe trigeminal nerve contains both sensory and motor fibres. It is responsible for sensation in the face and certain motor functions such as biting, chewing, and swallowing. Sensory information from the face and body is processed by parallel pathways in the central nervous system...
(CN V) - maxillary nerve, the V2 branch of CN V
- oculomotor nerve
Unlike the nerves listed above, the abducens nerve (CN VI) does not run within the lateral wall of the cavernous sinus; rather, it runs through the middle of the sinus alongside the internal carotid artery
Internal carotid artery
In human anatomy, the internal carotid arteries are two major arteries, one on each side of the head and neck. They arise from the common carotid arteries where these bifurcate into the internal and external carotid artery, and they supply the brain....
.
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.
- horizontally, from medial to lateral
- internal carotid arteryInternal carotid arteryIn human anatomy, the internal carotid arteries are two major arteries, one on each side of the head and neck. They arise from the common carotid arteries where these bifurcate into the internal and external carotid artery, and they supply the brain....
(and sympathetic plexus). See also cavernous part of internal carotid artery.
- internal carotid artery
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.
One mnemonic for remembering the contents is "OTOM CAT"
Venous connections
It receives tributaries from:- SuperiorSuperior ophthalmic veinThe superior ophthalmic vein begins at the inner angle of the orbit in a vein named the nasofrontal which communicates anteriorly with the angular vein; it pursues the same course as the ophthalmic artery, and receives tributaries corresponding to the branches of that vessel.Forming a short single...
and inferior ophthalmic veinInferior ophthalmic veinThe inferior opthalmic vein begins in a venous net-work at the forepart of the floor and medial wall of the orbit; it receives some vorticose veins and other veins from the Rectus inferior, Obliquus inferior, lacrimal sac and eyelids, runs backward in the lower part of the orbit and divides into...
s - Sphenoparietal sinusSphenoparietal sinusThe cavernous sinus receives the superior ophthalmic vein through the superior orbital fissure, some of the cerebral veins, and also the small sphenoparietal sinus, which courses along the under surface of the small wing of the sphenoid....
- Superficial middle cerebral veins
The veins of exit are to the superior and inferior petrosal sinus
Inferior petrosal sinus
The inferior petrosal sinuses, within the human head, are beneath the brain and allow blood to drain from the center of the head.They drain on either side inferiorly from the cavernous sinus and join with the sigmoid sinus to form the internal jugular vein, which continues inferiorly to drain...
es as well as via the emissary veins
Emissary veins
The emissary veins are valveless veins which normally drain external veins of the skull into the dural venous sinuses. However, because they are valveless, pus can flow into the skull through them as well, making them a possible route for transmission of extracranial infection to get into the...
through the foramina of the skull (mostly through foramen ovale
Foramen ovale
There are multiple structures in the human body with the name foramen ovale :* In the fetal heart, the foramen ovale is a shunt from the right atrium to left atrium....
).
There are also connections with the pterygoid plexus
Pterygoid plexus
The pterygoid plexus is a venous plexus of considerable size, and is situated between the temporalis muscle and lateral pterygoid muscle, and partly between the two pterygoid muscles.-Tributaries received:...
of veins via inferior ophthalmic vein
Inferior ophthalmic vein
The inferior opthalmic vein begins in a venous net-work at the forepart of the floor and medial wall of the orbit; it receives some vorticose veins and other veins from the Rectus inferior, Obliquus inferior, lacrimal sac and eyelids, runs backward in the lower part of the orbit and divides into...
, deep facial vein
Deep facial vein
The anterior facial vein receives a branch of considerable size, the deep facial vein, from the pterygoid venous plexus.-External links:* http://www.dartmouth.edu/~humananatomy/figures/chapter_47/47-5.HTM...
and emissary veins.
Clinical significance
It is the only anatomic location in the body in which an arteryArtery
Arteries are blood vessels that carry blood away from the heart. This blood is normally oxygenated, exceptions made for the pulmonary and umbilical arteries....
travels completely through a venous structure. If the internal carotid artery ruptures within the cavernous sinus, an arteriovenous fistula
Arteriovenous fistula
An arteriovenous fistula is an abnormal connection or passageway between an artery and a vein. It may be congenital, surgically created for hemodialysis treatments, or acquired due to pathologic process, such as trauma or erosion of an arterial aneurysm....
is created (more specifically, a carotid-cavernous fistula
Carotid-cavernous fistula
A carotid-cavernous fistula results from an abnormal communication between the arterial and venous systems within the cavernous sinus in the skull. It is a type of arteriovenous fistula...
). Lesions affecting the cavernous sinus may affect isolated nerves or all the nerves traversing through it.
The pituitary gland
Pituitary gland
In vertebrate anatomy the pituitary gland, or hypophysis, is an endocrine gland about the size of a pea and weighing 0.5 g , in humans. It is a protrusion off the bottom of the hypothalamus at the base of the brain, and rests in a small, bony cavity covered by a dural fold...
lies between the two paired cavernous sinuses. An abnormally growing pituitary adenoma
Pituitary adenoma
Pituitary adenomas are tumors that occur in the pituitary gland, and account for about 15% of intracranial neoplasms. Tumors which exceed 10 mm in size are defined as macroadenomas, and those smaller than 10 mm are referred to as microadenomas...
, sitting on the bony sella turcica
Sella turcica
-External links:*...
, 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
Ophthalmoparesis
Ophthalmoparesis or ophthalmoplegia refers to paralysis of one or more extraocular muscles which are responsible for eye movements. It is a physical finding in certain neurologic illnesses.-Classification:...
(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.
Because of its connections with the facial vein via the superior ophthalmic vein
Superior ophthalmic vein
The superior ophthalmic vein begins at the inner angle of the orbit in a vein named the nasofrontal which communicates anteriorly with the angular vein; it pursues the same course as the ophthalmic artery, and receives tributaries corresponding to the branches of that vessel.Forming a short single...
, it is possible to get infections in the cavernous sinus from an external facial injury within the Danger area of the face. This is especially likely as the facial vein has no valves, allowing blood to pass in both directions. In patients with thrombophlebitis
Thrombophlebitis
Thrombophlebitis is phlebitis related to a thrombus . When it occurs repeatedly in different locations, it is known as "Thrombophlebitis migrans" or "migrating thrombophlebitis".-Signs and symptoms:...
of the facial vein, pieces of the clot may break off and enter the cavernous sinus, forming a cavernous sinus thrombosis
Cavernous sinus thrombosis
Cavernous sinus thrombosis is the formation of a blood clot within the cavernous sinus, a cavity at the base of the brain which drains deoxygenated blood from the brain back to the heart. The cause is usually from a spreading infection in the nose, sinuses, ears, or teeth. Staphylococcus aureus...
. From there the infection may spread to the dural venous sinuses
Dural venous sinuses
The dural venous sinuses are venous channels found between layers of dura mater in the brain...
. Infections may also be introduced by facial lacerations and by bursting pimples in the areas drained by the facial vein.
Potential causes of cavernous sinus syndrome include metastatic tumors, direct extension of nasopharyngeal tumors, meningioma, pituitary tumors or pituitary apoplexy, aneurysms of the intracavernous carotid artery, cavernous-carotid arteriovenous fistula, bacterial infection causing cavernous sinus thrombosis, aseptic thrombosis, idiopathic granulomatous disease (Tolosa-Hunt syndrome
Tolosa-Hunt syndrome
Tolosa-Hunt syndrome is a rare disorder characterized by severe and unilateral headaches with extraocular palsies, usually involving the third, fourth, fifth, and sixth cranial nerves, and pain around the sides and back of the eye, along with weakness and paralysis of certain eye muscles.In 2004,...
), and fungal infections. Cavernous sinus syndrome is a medical emergency, requiring prompt medical attention, diagnosis, and treatment.