plural of sinus node

(anatomy) Synonym of sinoatrial node.

plural of sinus rhythm

(medicine) any cardiac rhythm in which depolarization of the myocardium begins at the sinus node, characterised by the presence of correctly oriented P waves in an electrocardiogram

(anatomy) A small but richly innervated arterial enlargement that is located near the point in the neck where either carotid artery divides to form its main branches and that functions in the regulation of heart rate and blood pressure.

(anatomy) Either of a pair of large venous sinuses situated in a groove at the side of the body of the sphenoid bone in the cranial cavity and opening behind into the petrosal sinuses.

plural of sinus venosus

(zootomy) The first chamber of the heart in fish, amphibians, and reptiles, emptying into the right atrium.

(anatomy) A large vein or passage (as the canal of Schlemm) for venous blood. / (anatomy) Alternative form of sinus venosus.

(anatomy) Either of two large venous sinuses of the cranium that begin at the bony protuberance on the middle of the inner surface of the occipital bone at the intersection of its bony ridges and that terminate at the jugular foramen on either side to become the internal jugular vein.