Sinus may refer to:

Anatomy

* Sinus (anatomy), a sac or cavity in any organ or tissue **

Paranasal sinuses Paranasal sinuses are a group of four paired air-filled spaces that surround the nasal cavity. The maxillary sinuses are located under the eyes; the frontal sinuses are above the eyes; the ethmoidal sinuses are between the eyes and the sphenoid ...

, air cavities in the cranial bones, especially those near the nose, including: *** Maxillary sinus, is the largest of the paranasal sinuses, under the eyes, in the maxillary bones *** Frontal sinus, superior to the eyes, in the frontal bone, which forms the hard part of the forehead ***

Ethmoid sinus The ethmoid sinuses or ethmoid air cells of the ethmoid bone are one of the four paired paranasal sinuses. The cells are variable in both size and number in the lateral mass of each of the ethmoid bones and cannot be palpated during an extraoral e ...

, formed from several discrete air cells within the ethmoid bone between the eyes and under the nose *** Sphenoidal sinus, in the sphenoid bone at the center of the skull base under the pituitary gland **

Anal sinuses The anal sinuses (rectal sinuses) are furrows in the anal canal, that separate the anal columns from one another. The anal sinuses end below in small valve-like folds, termed anal valves The anal valves are small valve-like folds at the lower ends ...

, the furrows which separate the columns in the rectum **

Dural venous sinuses The dural venous sinuses (also called dural sinuses, cerebral sinuses, or cranial sinuses) are venous channels found between the endosteal and meningeal layers of dura mater in the brain. They receive blood from the cerebral veins, receive cereb ...

, venous channels found between layers of dura mater in the brain *

Sinus (botany) In botany, a sinus is a space or indentation between two lobes or teeth, usually on a leaf. The term is also used in mycology. For example, one of the defining characteristics of North American species in the ''Morchella elata'' clade of morel ...

, a space or indentation, usually on a leaf

Heart

* Sinus node, a structure in the superior part of the right atrium * Sinus rhythm, normal beating on an ECG * Coronary sinus, a vein collecting blood from the heart * Sinus venosus, a cavity in the heart of embryos * Sinus venarum, a part of the wall of the right atrium in adults, developed from the sinus venosus

Other uses

* Sinus (Chalcidice), a town of ancient Chalcidice, Greece * ''Sinus'', gulf or bay in Latin, used in numerous toponyms in ancient writing (e.g.,

Sinus Magnus The Magnus Sinus or Sinus Magnus (Latin; grc-gre, ὀ Μέγας Κόλπος, ''o Mégas Kólpos''), also anglicization of names, anglicized as the was the form of the Gulf of Thailand and South China Sea known to Greek geographers, Greek, Roma ...

, Sinus Flanaticus, etc.) *

Sine In mathematics, sine and cosine are trigonometric functions of an angle. The sine and cosine of an acute angle are defined in the context of a right triangle: for the specified angle, its sine is the ratio of the length of the side that is oppo ...

, a trigonometric math function (Latin ''sinus'')

Anatomy

Heart

Other uses

See also