An overview of cardiac embryology is essential for understanding the development of the coronary system. During the third to fifth weeks of development, the cardiogenic zone of the mesoderm turns into a horseshoe-shaped endocardial tube. The pericardial space is formed from the space around this tube. By the end of the third week, the two legs of the endocardial tube start to contract rhythmically and join one another to become the heart tube, known as the cor tubulare simplex. It consists of the sinus venosus, a pair of primitive atria, a primitive ventricle, and the conus arteriosus. During the fourth and fifth weeks, the heart tube morphs into an S shape known as the cor sigmoideum. The connection between the primitive atria and ventricle is modified by the atrioventricular canal. As development progresses, structures change location. The endocardial cushion forms the caps for the atrioventricular valves. By the fifth to sixth weeks, the heart has two ventricles and the pars muscularis of the septum interventriculare has formed. However, the ventricles are still connected to one another. Once the pars membranacea of the interventricular septum has completed its development during week seven, the lumina of the two ventricles are completely and irreversibly separated. The conus arteriosus twists into a spiral and the truncus pulmonalis and the aorta are formed from the saccus aorticus attached to it. The arteries to the head and neck area come off the saccus aorticus. Once the aorta forms, adult coronary artery development begins (Sharma et al. 2017).