Cell extravasation is a crucial step in the metastatic cascade, whereby circulating tumor cells adhere to the endothelial cell monolayer (EM) wall and pass through it, allowing them to invade different organs. For this event to occur, cell–cell adhesions in the EM break down, creating intracellular gaps allowing tumor cells intra/extravasate the blood vessel wall. Finite Element simulation is a valuable computational tool for understanding the influence of various parameters, such as substrate stiffness and friction between the EM and substrate, on cell–cell adhesion behavior and, therefore, cell–cell junctions rupture. To produce an accurate Finite Element simulation of the EM, a reliable geometry is essential. This is a challenging task, as it requires the observation of a monolayer sample in the human body or its in vitro generation in the laboratory, the subsequent image processing of this data is also a time-consuming and not easy task. In fact, in the human body, vessel radii range from about 8 μm in capillaries to more than 1 cm in large arteries. Thus, we propose an alternative to this procedure, using a simplified parametric geometry of the EM able to be adapted to a wide range of vessel geometries. The parametric geometry was developed using CAD software SolidWorks. This model allows an easy modification of the size and shape of the cells and cell–cell adhesion, as well as the monolayer curvature or the geometry and characteristics of the substrate by simply modifying the model defining parameters in a table to simulate different blood vessels.