sinus venosus

== English == === Alternative forms === (pouch adjoining the heart): venous sinus === Etymology === Unadapted borrowing from New Latin sinus vēnōsus (“venous hollow”). === Pronunciation === (Received Pronunciation) IPA(key): /ˌsʌɪ.nəs viːˈnəʊ.səs/ (General American) IPA(key): /ˌsaɪ.nəs ˌviˈnoʊ.səs/ Rhymes: -əʊsəs === Noun === sinus venosus (plural sinus venosi) (zootomy) The first chamber of the heart in fish, amphibians, and reptiles, emptying into the right atrium. (anatomy) An enlarged pouch that adjoins the heart, is formed by the union of the large systemic veins, and is the passage through which venous blood enters the heart in lower vertebrates and in embryos of higher forms. ==== Translations ==== === References === “sinus venosus”, in Merriam-Webster.com Online Dictionary, Springfield, Mass.: Merriam-Webster, 1996–present.