Fig. 6.

Schematic model of the anterior portion of the arterial circle in contact with the interpubic disc. Blood flow is increased in the muscular zone (A) through the contraction of muscular tissue (+++). When blood reaches the fibro-fatty zone (B), the flow decreases (++) because of lack of contraction and compliance of the tissue. At the interface between this zone and the fibrous zone (C), which corresponds to the fibrous rim, capillaries adopt a winding and spiralling morphology that decreases the blood flow even further (+) and increases the contact area to optimize supply. Further contraction of the muscular zone guarantees blood drainage (+++) through compression of the venous system.