- fistula, sinus - an abnormal passage leading from a suppurating cavity to the body surface
--1 is a kind of passage, passageway
- sinus - any of various air-filled cavities especially in the bones of the skull
--2 is a kind of cavity, bodily cavity, cavum
--2 has particulars:ethmoid sinus, ethmoidal sinus, sinus ethmoidales; frontal sinus; maxillary sinus; paranasal sinus, sinus paranasales, nasal sinus - venous sinus, sinus - a wide channel containing blood; does not have the coating of an ordinary blood vessel
--3 is a kind of duct, epithelial duct, canal, channel
--3 has particulars:cavernous sinus, sinus cavernosus; coronary sinus, sinus coronarius; sigmoid sinus, sinus sigmoideus; straight sinus, tentorial sinus, sinus rectus; transverse sinus, sinus transversus - venous sinus, sinus - a wide channel containing blood; does not have the coating of an ordinary blood vessel