Anatomical Study of Coronary Sinus and Thebesian Valve in Cadaveric Human Hearts.

Background and objective The coronary sinus (CS) is the principal venous channel of the heart, lying in the posterior atrioventricular groove and draining into the right atrium. At its ostium, the Thebesian valve (TV) serves as an anatomical guardian, varying considerably in morphology among individuals. These anatomical variations carry significant implications for catheter-based cardiac interventions, including CS cannulation, cardiac resynchronization therapy, and electrophysiological procedures. The objective of this study is to measure the length of the CS and to determine the prevalence and morphological types of the TV in cadaveric human hearts, as well as to assess their clinical significance. Methods Twenty formalin-fixed cadaveric human hearts were dissected at the Department of Anatomy, King George's Medical University, Lucknow, India. The specimen pool comprised 12 male and eight female donors with a mean age of 42.4 ± 11.1 years (range: 21-58 years). The length of the CS was measured using precision tools, and the TV was classified into four morphological types: semilunar, remnant, cord-like, and mesh-like. High-resolution photographic documentation was performed for all specimens. Results The CS was present in all 20 hearts. The mean length of the CS was 44.4 ± 7.3 mm (range: 31-58 mm). Mean CS length was greater in male specimens (48.9 ± 5.5 mm) compared to female specimens (37.6 ± 3.4 mm), consistent with known sex-related differences in cardiac dimensions. The TV was identified in 90% of specimens (18 out of 20), while it was absent in 10% (two out of 20). Among the valve types, the semilunar variety was most prevalent (35%), followed by remnant (25%), cord-like (20%), and mesh-like (10%) types. Chi-square analysis revealed no statistically significant difference in TV morphological type distribution between the present study and previously published series (χ² = 6.356, df = 6, p = 0.385). Conclusions Significant anatomical variability exists in both CS length and TV morphology in the study population. Sex-related differences in CS length were noted and warrant further investigation in larger samples. These variations carry important implications for catheter-based cardiac procedures. The present study contributes population-specific anatomical data from the Indian subcontinent that may inform the planning and execution of interventional cardiac procedures, thereby supporting improved clinical outcomes.