Anatomical Variation of the Left Coronary Artery: Description of a Case of Trifurcation With Intermediate Branch

The left coronary artery (LCA), in its classic pattern, divides into two main branches: the anterior interventricular and circumflex branches. However, anatomical variations can occur, including the presence of additional branches, commonly referred to as intermediate branches. This study describes a case of LCA trifurcation, identified during routine dissection of a specimen belonging to the Human Anatomy Laboratory of the Amazonas State University. After exposure of the coronary system, the emergence of an intermediate branch was observed, which was subjected to morphometric analysis using a digital caliper. The vessel measured 1.8 mm in diameter, 39.2 mm in length, and originated approximately 14.2 mm from the beginning of the LCA. Although bifurcation is the most prevalent form of branching, the occurrence of trifurcation reinforces the morphological complexity and diversity of coronary variations. Furthermore, although often not associated with functional repercussions, such variations may, under specific circumstances, represent a predisposing factor for atherosclerosis and ischemic events, highlighting the importance of their anatomical documentation.