It is a closed sac having two layers: the visceral layer (epicardium), immediately surrounding the heart, and the outer parietal layer, forming the sac, composed of strong fibrous tissue, the fibrous pericardium, lined with a serous membrane, the serous pericardium. Synonym(s): heart sac, theca cordis.
The right and left cavernous sinuses are interconnected by the anterior and posterior intercavernous sinuses. Tributaries of the cavernous sinus include the superior ophthalmic, superficial middle cerebral, and inferior cerebral veins and the sphenoparietal sinus.
Sphenoid sinus Medically reviewed by Healthline Medical Team on January 27, 2015 Sinuses are air-filled sacs (empty spaces) on either side of the nasal cavity that filter and clean the air breathed through the nose and lighten the bones of the skull. There are four paired sinuses in the head. The most posterior (farthest toward the back of the head) of these is the sphenoid sinus. The sphenoid sinuses are located in the sphenoid bone near the optic nerve and the pituitary gland on the side of the skull. There are seven bones that form the orbit (eye socket), and the sphenoid is one of these bones. The pituitary gland, which produces many different hormones that control other glands, is housed in the sphenoid bone.