The surgical anatomy of the mandibular distribution of the facial nerve.

There are many controversies about the course of the mandibular nerve in the submandibular region. In an attempt to resolve these and improve the safety of submandibular approaches a study was undertaken based on anatomical dissection and measurement of 110 facial halves. In over half the specimens the mandibular nerves ran below the mandible and a significant proportion continued below the mandible distal to the facial vessels. The nerves lay in a plane between the platysma and the investing fascia. These findings influence the placement and depth of incisions in the submandibular region and the margins of safety attainable.