The valvular segment is a distinct venous structure, which, from a morphological point of view, is comprised of the following components: the valvular insertion, the valvular gorge entrance orifice, the valvular defile, the valvular gorge exit orifice, the valvular sinus. Endoscopic and echo Doppler examinations are used to identify the normal and the pathological morphology of the valvular segment, and the hemodynamic phenomena occurring at this level. Cusps' integrity and size as well as valvular dynamics are key elements directly involved in shaping the valvular segment in general, and the valvular sinus in particular. The valvular sinus shows an obvious hemodynamic determinism. Valvular segment pathology is the outcome either of a progressively long evolving process initialized by gravitational venous pressure overcharges, or of a rapidly evolving process such as the hemodynamic shock following intense physical efforts. Valvular defunctionalisation implies a different mechanism and a different type of cusp lesion.