Study of Third Coronary Artery in Adult Human Cadaveric Hearts.

Introduction: Third coronary artery (TCA) is a direct branch arising from the anterior aortic sinus (right aortic sinus) which supplies right ventricular outflow tract. It is found frequently and may be an important source for collateral coronary blood flow through a vascular anastomotic bridge (circle of Vieussens) between the right and left coronary systems.

Aim: To evaluate the gross anatomy of third coronary artery in terms of their number, origin, extent and distribution.

Materials And Methods: After an ethical approval, 150 formalin fixed adult human cadaveric hearts were collected from Department of Anatomy, BVDU Medical College and Hospital, Sangli and Pune over the period of six years. The careful dissection was carried out to note details about third coronary artery and data was analysed using SPSS computer software.

Results: The TCA was present in 32% of the heart specimens. In 42 hearts (28%) single TCA and in 6 hearts (4%) double TCA were noted. It was found to be variably distributed to conus arteriosus, anterior wall of the right ventricle, interventricular septum and the apex of the heart. TCA was larger than right coronary artery in 8 hearts and later ended at inferior border of heart. Myocardial bridge was noted over large third coronary artery in one specimen.

Conclusion: TCA is present frequently. It anastomoses with branches of left anterior descending artery (LADA) and contributes to apical and septal perfusion. Hence role of TCA should always be considered during diagnostic and therapeutic interventions.