Left coronary artery divides into anterior interventricular branch and circumflex branch. As both the arteries run in their corresponding grooves, an arteriovenous trigone is formed between conus arteriosus and left auricle called triangle of Brocq and Mouchet. The triangle base is formed by great cardiac vein. This study aims to describe the frequency of triangle and its type and relationship between various boundaries and content of triangle and to supplement the existing knowledge of clinicians. This observational and descriptive study was conducted on 40 formalin fixed cadaveric hearts in department of anatomy, Kalpana chawla government medical college. The triangle was found in 92.5% of specimen with most common type being closed (51.3%) which is followed by inferiorly open in 35.1%, superiorly open in 8.1% and completely open in 5.4% hearts. Most frequent content of triangle was median artery followed by diagonal branches of anterior interventricular and circumflex branches. The mean area of the triangle was 246.3 mm2 . Relationship of vein with two arterial branches was either superficial or deep. The knowledge of different patterns of existence will be required for angiographic procedures. Further the triangle is a potential epicardial access route to left fibrous ring. Thus detailed knowledge of variations will help cardiologist to achieve better outcome in interventional procedures with minimal complications.