A detailed understanding of the coronary arteries is of paramount importance in the management of coronary arterial diseases. The arterial supply to the heart originates from right (RCA) and left (LCA) coronary arteries which form an oblique inverted crown within the atrioventricular groove. This study aimed to document the embryologic relationship between the RCA and the LCA including their lengths, diameters, branching patterns and arterial dominance in fetuses. Forty-one human fetal heart specimens with an age range of 13.13 to 26.95 weeks were dissected at the Department of Clinical Anatomy, University of Kwazulu-Natal, Durban, South Africa. The RCA arose from the right aortic sinus and was dominant in all the specimens. The LCA was classified into types according to their branching pattern. The bifurcation, trifurcation and quadrifurcation of the LCA occurred in 68.3 %, 29.3 % and 2.4 % of hearts, respectively. The mean lengths of the RCA and LCA were 0.98±0.54 mm and 1.83±0.77 mm, respectively. The mean external diameters of the RCA and LCA were 0.38±0.12 mm and 0.49±0.17 mm, respectively. There was a significant correlation between the RCA and LCA length and the fetal age which is indicative of significant changes in the coronary vasculature with fetal growth.
KEY WORDS: Right coronary artery; Left coronary artery; Branching patterns; Bifurcation; Trifurcation; Quadrifurcation.