Variations in the venous supply of the floor of the oral cavity: Assessment of relative hemorrhage risk during surgery

There is little anatomical evidence about the venous plexus in the floor of the oral cavity, although venous injury can elicit late postoperative bleeding after oral surgery and it is difficult to identify the exact location of such an injury. The aim of this study was to assess the relative risk for venous injury during surgery. We investigated the course patterns of the venous plexus in the floor of the oral cavity and analyzed their relationships to those of the arteries using 23 human cadavers (41 halves) in the anatomy course at Niigata University during 2016-2018. The venous plexus in the floor of the oral cavity comprised the perforating submental vein, the vena comitans of the hypoglossal nerve, the vena comitans of the submandibular duct, the vena comitans of the lingual nerve, the sublingual vein, and the deep lingual vein. Individual variations of this plexus include duplications or absences of some veins. There is a high incidence of a submental branch running above the mylohyoid or perforating submental artery in the sublingual fossa among individuals with the perforating submental vein piercing the mylohyoid muscle, whereas the sublingual artery has a high incidence there when there is no perforating submental vein. The course patterns of arteries in the floor of the oral cavity can be predicted by estimating the course patterns of the submental veins. The course patterns of the submental veins or veins associated with the nerves and submandibular duct need to be carefully considered during surgery.