Cavernous sinus

One of the dural venous sinuses, the cavernous sinuses sit on either side of the body of the sphenoid bone.  The cavernous sinus receives blood from the ophthalmic veins, which receive blood from cutaneous veins of the face.  This situation may allow a skin infection in the face (such as from acne) to spread into the cavernous sinus, which can then cause cavernous sinus thrombosis (a blood clot in the cavernous sinus, due to infection in this case).  Since several cranial nerves pass through the cavernous sinus (CN III, CN IV, CN V1, CN VI), a cavernous sinus thrombosis may lead to a pressure neuropathy, and a palsy in the eye on the affected side.  The smaller nerves, (CN IV and CN VI) are most prone to the effects of increased pressure in the cavernous sinus.