Third Coronary Artery: a Cadaveric Study

Introduction: The human heart is vascularised by the Third coronary artery apart from the right and the left coronary arteries. The Third coronary artery, also called Supernumerary coronary artery takes origin from the anterior aortic sinus of the heart. It plays a significant role in collateral circulation of heart in conditions of chronic hypoxia. Aim: The aim of the study is to delineate different morphological patterns of the Third coronary artery anatomy in adult human cadaveric hearts by dissection. The origin, course, branching of Third coronary artery (TCA) were studied in detail. Materials and Methods: The study was carried out on 50 formalin fixed normal adult human hearts obtained from the Department of Anatomy, Rajarajeshwari Medical College and Hospital. Specimens with gross congenital anomalies were excluded from the study. The right coronary artery, left coronary artery and the third coronary artery were carefully dissected and observations noted. Results: The frequency of third coronary artery observed in our study is 30%. The TCA and right coronary artery originated from a common ostium in the Anterior aortic sinus in most of the cases. We observed 2 third coronary arteries arising from anterior aortic sinus in 2 specimens.The third coronary artery frequently bifurcated to supply the pulmonary infundibulum and anterior wall of the right ventricle. It also reached the inferior border supplying the apex in 6% of the cases. Conclusions: The area of perfusion of the Third coronary artery is variable and may be more extensive than usual in some individuals. Well developed collateral circulation through TCA may allow diagnostic and therapeutic interventions in patients with coronary artery disease. The variant anatomy and the significant contribution of TCA to coronary perfusion necessitates the selective visualization and functional assessment of TCA in patients with coronary artery disease.