The world sinus literally means narrow passage. But in common medical knowledge of people it means the sinus cavities present in the facial region or some kind of infections to them. Hence whenever a medical term like 'what is cavernous sinus?' is used most of us would think that its some kind of infection of sinus. But the fact is that cavernous sinus is not related to any facial region or sinus cavities but our brain or head.
The cavernous sinus also called the lateral sellar compartment is found within our heads. This is a large collection of thin walled veins creating a cavity which is bordered by the temporal bone and the sphenoid bone and the skull.
If you ask a doctor about what is cavernous sinus he would explain you the above nerve cavity which acts as a cushion to the brain in the skull area and it contains the following pair of nerves. Vertically each cavernous sinus contains oculomotor nerve (CN III), ophthalmic nerve, the V1 branch of the trigeminal nerve (CN V), trochlear nerve (CN IV) and maxillary nerve, the V2 branch of CN V.
On horizontal look its found that the cavernous sinus contains internal carotid artery along with sympathetic plexus and abducens nerve (CN VI).
The tributaries of this sinus capillary are superior and inferior ophthalmic veins, Superficial middle cerebral veins and sphenoparietal sinus. If there is excessive growth of pituitary gland, this results in a compression of the cavernous sinuses. This condition is called cavernous sinus syndrome and it may result in neurological disorder like ophthalmoplegia, ophthalmic sensory loss, and maxillary sensory loss.