The left coronary artery (LCA) is the principal arterial supply to a major portion of the left ventricle, interventricular septum, and left atrium. It originates from the left posterior aortic sinus and typically divides into the left anterior descending artery (LAD) and left circumflex artery (LCx), although variations such as trifurcation or accessory branches are not uncommon.(1,2) Coronary angiography, stent deployment, and coronary artery bypass grafting (CABG) all rely on an accurate understanding of coronary anatomy. Minor deviations in vessel length, diameter, or branching configuration can alter hemodynamic flow, predisposing to atherosclerotic plaque formation or procedural complications. Although imaging modalities such as CT coronary angiography have provided in vivo insights, cadaveric dissection remains the gold standard for establishing precise morphometric baselines and for identifying population-specific variations. Previous studies from Western populations have reported an average left main coronary artery (LMCA) length of 10–15 mm and diameter of about 4–6 mm. However, morphometric data from Indian and other South Asian populations remain limited and variable. The present study was undertaken to document the morphometric parameters of the LCA and its major branches in adult human cadaveric hearts and to analyze their potential clinical relevance.

The present study was conducted on 53 formalin-fixed human hearts, irrespective of age and sex, obtained from the Department of Anatomy, SVIMS–SPMC(W), Tirupati, representing the Rayalaseema region of Andhra Pradesh. Specimens exhibiting gross pathological lesions, traumatic damage, or congenital cardiac anomalies were excluded from the study to ensure anatomical accuracy. All hearts were thoroughly washed and cleaned to remove pericardial fat and preserved in 10% formalin prior to dissection. Detailed dissection of the coronary arteries was performed to expose the left coronary artery (LCA) and its major branches — the left anterior descending (LAD) and left circumflex (LCx) arteries. Morphometric measurements were obtained using a digital Vernier caliper for diameter estimation, non-elastic thread and a ruler for length measurements, and a protractor for angular assessment. All observations were systematically recorded, tabulated, and statistically analyzed. Parameters Recorded 1. Angle of Division of the Left Coronary Artery (LCA): The angle formed between the LAD and LCx arteries at the point of bifurcation or trifurcation was measured using a protractor. This helped assess the divergence pattern of the LCA. 2. Length Measurements: Lengths were measured using thread and a scale: LCA: From its origin at the left posterior aortic sinus to its point of bifurcation/trifurcation. LAD: From the point of division of the LCA to its termination (before, at, or beyond the apex). LCx: From the point of division of the LCA to its termination (before obtuse border, at obtuse border, or near the crux). 3. External Diameter Measurements: Using a digital Vernier caliper, the outer diameter was measured at: The midpoint of the LCA. The origin of the LAD at the site of division of the LCA. The origin of the LCx at the site of division of the LCA.

In the present study, the angle is measured between LAD and CA at the level of bifurcation of LCA. The mean angle and standard deviation are 81.77 ± 15.94. Length & outer diameter of LCA & its branches (LAD & CA): In the present study, the mean length and standard deviation of the LCA is 15.92 ± 4.24, the mean outer diameter & standard deviation of the LCA is 4.52 ± 0.76. The mean length and standard deviation of the LAD is 105.17 ± 25.68, the mean outer diameter and standard deviation of LAD is 3.54 ± 0.63, whereas the mean length and standard deviation of CA is 53.77 ± 14.46, the mean outer diameter and standard deviation of CA is 2.86 ± 0.63 are observed. Table.1: Mean length & outer diameter of LCA and its branches (LAD & CA) Name of the artery Mean Length & SD (in mm) Mean outer Diameter & SD (in mm) Left coronary artery (LCA) 15.92 ± 4.24 4.52 ± 0.76 Left anterior descending artery (LAD) 105.17 ± 25.68 3.54 ± 0.63 Circumflex artery (CA) 53.77 ± 14.46 2.86 ± 0.63

The present study provides valuable baseline data on the morphometry of the left coronary artery in cadaveric hearts of the Rayalaseema population. The present findings were analyzed in detail and compared with previous studies to identify similarities and variations in the morphometry of the left coronary artery across different populations. In the present study, the angle between the left anterior descending artery (LAD) and the left circumflex artery (LCx) at the level of bifurcation of the left coronary artery (LCA) ranged from 60° to 120°, with a mean angle of 81.77° ± 15.94°. The mean length and outer diameter of the LCA, LAD, and LCx were measured and statistically analyzed. The mean length of the LCA was 15.92 ± 4.24 mm, and the mean outer diameter was 4.52 ± 0.76 mm. The mean length of the LAD was 105.17 ± 25.68 mm, with an outer diameter of 3.54 ± 0.63 mm. The mean length of the LCx was 53.77 ± 14.46 mm, with an outer diameter of 2.86 ± 0.63 mm. Table.2: Comparative table for the mean length of LCA Name of the author and year Mean Length and SD of the LCA in mm Green G E, et.al., (1967) (3) 17.5 B Pejkovic et al., (2008) (4) 9.8 L.E. Ballesteros,et.al.,(2008) (5) 6.48 ± 2.57 Dattatray D. Dombe, et.al., (2012) (6) 11.2 ± 3.6 Mamatha Hosapatna, MBBS, MD, et.al.,(2013) (7) 8.86 ± 2.96 P. Dharmendra, et.al., (2013) (8) 9.2 ± 0.31 S Udhaya Kumar et al., (2014) (9) 8.33 ± 3.7 Sulthana Ruma Alam, et.al., (2017) (10) 12.5 Vandana Ravi et al., (2017) (11) ¬14.5 ± 4.42 Anil Kumar, et al., (2018) (12) 10.2 ± 3.5 Present study 15.92 ± 4.24 The present study provides valuable morphometric data on the left coronary artery and its branches in cadaveric hearts from the Rayalaseema region. The findings were compared with those of previous anatomical studies to identify similarities and regional variations. In the present study, the mean length of the LCA was 15.92 ± 4.24 mm, which closely correlates with the findings of Green GE et al. (1967), Dattatray D. Dombe et al. (2012), Sulthana Ruma Alam et al. (2017), Vandana Ravi et al. (2017), and Anil Kumar et al. (2018). However, our results were slightly higher than those reported by Ballesteros (2008) and Mamatha Hosapatna (2013), who recorded shorter mean lengths (6.48 mm and 8.86 mm, respectively). This variation could be attributed to ethnic, geographical, or methodological differences among populations. The mean outer diameter of the LCA in this study was 4.52 ± 0.76 mm, which correlates closely with the findings of Dombe (2012), Dharmendra (2013), and Anil Kumar (2018), who reported diameters ranging between 4.3–4.6 mm. Table.3: Comparative table for outer diameter of LCA Name of the author Mean outer diameter and SD of the LCA L.E. Ballesteros, et.al.,(2008) (5) 3.58 ± 0.59 B Pejkovic, et.al.,(2008) (4) 4.1 Dattatray D. Dombe, et.al., (2012) (6) 4.64 ± 1.03 P. Dharmendra, et.al., (2013) (8) 4.64 ± 1.03 S Udhaya Kumar et al., (2014) (9) 3.14 ± 0.4 Anil Kumar, et al., (2018) (12) 4.34 ± 2.01 Present study 4.52 ± 0.76 The mean length of LAD in this study was 105.17 ± 25.68 mm, which is higher than that reported by Dombe (2012) (85 mm) and Anil Kumar (2018) (83.4 mm). The difference may reflect population variations or differences in the methods used to define the termination point of LAD. The mean length of the LCx was 53.77 ± 14.46 mm, which is slightly higher than previous findings by Dombe (2012) and Anil Kumar (2018), who reported average lengths around 45 mm.In the current study, the mean outer diameter of the LAD was 3.54 ± 0.63 mm, and that of the LCx was 2.86 ± 0.63 mm, which correspond well with earlier anatomical findings. Table-4 : Comparative table for outer diameter of LAD Name of the author Mean outer diameter of LAD Length of CA Mean outer diameter and SD of CA L.E. Ballesteros, et.al.,(2008) (5) 2.94 ± 0.5 mm 2.71 ± 0.54 mm Dattatray D. Dombe, et.al., (2012) (6) 3.19 ± 0.55 mm. 45.6 ± 19.9 mm. 2.94 ± 0.7 mm Anil kumar, et.al.,(2018) (12) 4.21 ± 0.28mm. 44.6 ± 17.9mm 2.73 ± 0.6mm Present study 3.54 ± 0.63mm 53.77 ± 14.46mm 2.86 ± 0.63 mm The mean angle between the LAD and LCx in this study was 81.77 ± 15.94°, comparable to the findings of Pejkovic et al. (2008), who reported a mean bifurcation angle of 86° (range 60–120°). The similarity indicates consistency across populations and suggests limited regional variation.

The present cadaveric study provides comprehensive morphometric data on the left coronary artery (LCA) and its major branches in the regional population of Rayalaseema. The left main coronary artery (LMCA) in this study exhibited a mean length and diameter consistent with values reported in most Indian series. By establishing baseline morphometric parameters for this population, the study contributes to a better anatomical understanding of coronary architecture, which can assist cardiologists, interventional radiologists, and cardiac surgeons in precise procedural planning and reducing iatrogenic complications. Further studies with larger sample sizes and advanced imaging correlation are recommended to validate and expand upon these findings.

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