Left horn of sinus venosus forms:: (A) Coronary sinus, (B) Smooth part of right atrium, (C) Superior vena cava, (D) Inferior vena cava
Answer is A. Ans. A Coronary sinusRef: Netter's Atlas of Human Embryology: 2012 ed. pg. 96Heart tube embryonic derivativesembryonic structureGives rise to* Proximal 1/3rd of bulbus cordisPrimitive trabeculated left ventricle* Middle 1/3rd of bulbus cordisRight and left ventricular outflow tract* Distal 1/3rd of bulbus cordis (truncus arteriosus)Ascending 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)