<prompt> Left horn of sinus venosus forms:Coronary sinusSmooth part of right atriumSuperior vena cavaInferior vena cava  <response>: Ans. A Coronary sinusRef: Netters Atlas of Human Embryology: 2012 ed. pg. 96Heart tube embryonic derivativesembryonic structureGives rise to Proximal 13rd of bulbus cordisPrimitive trabeculated left ventricle Middle 13rd of bulbus cordisRight and left ventricular outflow tract Distal 13rd of bulbus cordis truncus arteriosusAscending aorta and pulmonary trunk Left horn of sinus venosusCoronary sinus Right horn of sinus venosusSmooth part of right atrium Right common cardinal nerve and right anterior cardinal nerveSVC superior vena cava 