Sinus may refer to:

Anatomy

Sinus (anatomy) A sinus is a sac or cavity in any organ or tissue, or an abnormal cavity or passage caused by the destruction of tissue. In common usage, "sinus" usually refers to the paranasal sinuses, which are air cavities in the cranial bones, especially t ...

, 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 The pyramid-shaped maxillary sinus (or antrum of Highmore) is the largest of the paranasal sinuses, and drains into the middle meatus of the nose through the osteomeatal complex.Human Anatomy, Jacobs, Elsevier, 2008, page 209-210 Structure It is ...

, is the largest of the paranasal sinuses, under the eyes, in the maxillary bones ***

Frontal sinus The frontal sinuses are one of the four pairs of paranasal sinuses that are situated behind the brow ridges. Sinuses are mucosa-lined airspaces within the bones of the face and skull. Each opens into the anterior part of the corresponding middle na ...

, 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 The sphenoid sinus is a paired paranasal sinus occurring within the within the body of the sphenoid bone. It represents one pair of the four paired paranasal sinuses.Illustrated Anatomy of the Head and Neck, Fehrenbach and Herring, Elsevier, 2012, ...

, 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 The sinoatrial node (also known as the sinuatrial node, SA node or sinus node) is an oval shaped region of special cardiac muscle in the upper back wall of the right atrium made up of cells known as pacemaker cells. The sinus node is approximat ...

, a structure in the superior part of the right atrium *

Sinus rhythm A sinus rhythm is any cardiac rhythm in which depolarisation of the cardiac muscle begins at the sinus node. It is characterised by the presence of correctly oriented P waves on the electrocardiogram (ECG). Sinus rhythm is necessary, but not su ...

, normal beating on an ECG *

Coronary sinus In anatomy, the coronary sinus () is a collection of veins joined together to form a large vessel that collects blood from the heart muscle ( myocardium). It delivers deoxygenated blood to the right atrium, as do the superior and inferior ven ...

, a vein collecting blood from the heart *

Sinus venosus The sinus venosus is a large quadrangular cavity which precedes the atrium on the venous side of the chordate heart. In mammals, it exists distinctly only in the embryonic heart, where it is found between the two venae cavae. However, the sinus ve ...

, a cavity in the heart of embryos *

Sinus venarum The sinus venarum (also known as the sinus of the vena cava, or sinus venarum cavarum) is the portion of the right atrium in the adult human heart where the inner surface of the right atrium is smooth. The sinus venarum represents the portion of th ...

, a part of the wall of the right atrium in adults, developed from the sinus venosus

Other uses

Sinus (Chalcidice) Sinus or Sinos ( grc, Σίνος) was a town of the Chalcidice in ancient Macedonia. It belonged to the Delian League since it appears in the tribute records of Athens of 434/3 and 433/2 BCE, where it paid a ''phoros'' of 1500 drachmas Th ...

, 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 The Kvarner Gulf (, or , la, Sinus Flanaticus or ), sometimes also Kvarner Bay, is a bay in the northern Adriatic Sea, located between the Istrian peninsula and the northern Croatian Littoral mainland. The bay is a part of Croatia's internal wat ...

, 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