Sinus

(si’-mts) [sinus,. a gulf or hollow]. I. A hollow or cavity; a rece or pocket. 2. A large channel containing blood, especially one containing venous blood. 3. A suppurating tract. S., Air-, a cavity within bones containing air, especially one communicating with the nasal pa ages. S., Aortic. See S. of Valsalva. S., Cavernous, a large venous S. extending from the sphenoid fi ure to the apex of the petrous portion of the temporal bone, communicating behind with the inferior and superior petrosal sinuses and receiving the ophthalmic vein in front. S., Circular, a venous S. surrounding the pituitary body, and communicating on each side with the cavernous S. S., ch668.xhtml c 585