A review of the intraosseous course of the nerves of the mandible.

A review of the literature revealed that a common feature of all human mandibles is a large nerve (inferior alveolar nerve, IAN) between the mandibular and mental foramina. This nerve sends branches directly to the teeth or contributes a variable number of branches to a plexus of nerves which does the same. The plexus originates from a separate nerve that enters the mandibular foramen. The nerve plexus has been demonstrated by dissections and not by radiology. The buccal-lingual and superior-inferior positions of the IAN were not consistent among mandibles. The intramandibular IAN frequently ran a concave curve with a posterior segment descending as it progressed anteriorly and an anterior segment that ascended to the mental foramen. A bony canal was not always observed between the mandibular and mental foramina. The canal frequently lacked definite walls, especially near the mental foramen. Bilateral symmetry (location of the canal in each half of the mandible) was common, whereas duplications of the canal were rare. Nutrient canals and other branches of the mandibular nerve have been observed within the mandible. These may have been confused for the IAN or may contribute to the plexus of nerves.