What is the cavernous sinus?
The cavernous sinus is a venous blood conductor of the human brain. The name Sinus cavernosus comes from the Latin.
Sinus means translated into German as "heart", "bag" or "bag". The term cavernosus is derived from the Latin word Cavus (cavity or cave). The cavernous sinus is part of the cerebral blood duct (sinus durae matris). These provide for the outflow of blood from the brain region. In the area of the cavernous sinus, various diseases can occur.
Anatomy & Construction
The cavernous sinus is found on both sides of the sella turcica (Turkish saddle), which lies on the inside of the sphenoid (sphenoid sphenoid). This bone structure divides the middle fossa in the median plane.
The cerebral blood conductor is located at the anterior cranial base, where it forms a vein space within the dura mater. In the cavernous sinus, inflow from the inferior orbital vein (inferior vena cava), the superior orbital vein (superior vena cava) and the sphenoparietal sinus occur. Occasionally, the sylvic vein (superficial cerebral vein) is taken up by the vein space. The outflow of the cavernous sinus into the bulbus superior jugular vein takes place through the inferior petrosal sinus.
The lateral wall of the dilated vein space contains several cranial nerves. These are the third cranial nerve (oculomotor nerve), the fourth cranial nerve (trochlear nerve), the ocular nerve (ophthalmic nerve), the maxillary nerve (maxillary nerve) and the internal carotid artery (ACI). Directly through the cavernous sinus runs the sixth cranial nerve, which is also called the abducens nerve.
Function & Tasks
The cavernous sinus fulfills the function of providing direct access to several important cranial nerves as well as the internal carotid artery, allowing them to innervate various areas of the organism. Furthermore, the cavernous sinus transports the blood from the facial area back towards the heart.
In addition, it has a share in the fact that secreted hormones from the adenohypophysis cross the venous space and thus enter the circulation of the human body. This allows them to develop effectively. Hormones of the adenohypophysis (pituitary anterior lobes) include glandotropic and non-glandotropic hormones. While glandotropic hormones have a stimulating effect on downstream endocrine glands, non-glandotropic hormones have an immediate effect on their target organs. Non-glandotropic hormones include prolactin and the growth hormone somatotropin (STH).
Around the cavernous sinus are the cranial nerves that control the movements of human eyes. In addition, they perceive sensations from parts of the facial region.
The cavernous sinus can be affected by several diseases and complaints. These include, for example, fractures of the skull, the formation of tumors, Tolosa-Hunt syndrome or basal meningitis.
However, one of the most common problems of the vein space is the formation of a carotid-cavernous sinus fistula. This is an abnormal connection between the cavernous sinus and a carotid artery. The inner and outer carotid arteries supply the brain with blood. In some people, however, the arteries sometimes form a tear. If this process takes place near the cavernous sinus, there is a risk of canal formation. Such an unnatural channel is referred to by physicians as a fistula.
Through this fistula the blood, which normally flows through the artery, is diverted into the vein. Not infrequently, the fistula causes increased pressure within the cavernous sinus. As a result, the affected nerves are compressed and suffer functional loss. The veins leading away from the eye can also be affected by the pressure increase. This is noticeable through visual disturbances and swollen eyes.
Doctors distinguish between a direct and an indirect carotid sinus cavernosis fistula. In a direct carotid sinus cavernous fistula, there is a connection between parts of the internal carotid artery and the veins within the cavernous sinus. This form is most common and is characterized by increased blood flow velocity. An indirect carotid sinus cavernous fistula is mentioned when the unnatural connection between the cavernous sinus veins and the branches within the carotid artery forms in the brain-walled membranes. This is noticeable by a low blood flow velocity in the fistula.
Responsible for the development of a direct carotid sinus cavernous fistula are injuries caused by accidents or fights as well as operations. In contrast, the cause of an indirect fistula is unknown. Another disease of the venous plexus is the sinus cavernous syndrome dar. The eyes of the affected persons suffer from multiple paralysis. There are also sensory losses of the upper part of the face and the cornea as well as significant headache.
Responsible for the sinus cavernous syndrome is a pressure injury in the cavernous sinus, which leads to a partial or complete failure of various cranial nerves. Possible causes include thrombosis, tumors, bleeding, trauma or aneurysms on the nerve tracts.
The most serious diseases of the cavernous sinus include cavernous sinus thrombosis. So this can have life-threatening consequences. The thrombosis is caused by the spread of a bacterial inflammation, which in turn arises from a sinusitis. There is also the risk of soft tissue inflammation spreading from the upper facial region. The cavernous sinus thrombosis is notable for headache, seizures, numbness on the face, chills, fever, vomiting, eye muscle paralysis and double vision.