Mental Nerves in the Lower Lip: Anatomical Basis for the Recovery of Sensation following Inferior Alveolar Nerve Damage.

Abstract

Inferior alveolar nerve damage is one of the most common complications of surgery on the lower third of the face. It can have a significant psychological and social impact, and its evolution varies in terms of the duration and degree of recovery. In the literature, few studies adequately explain this phenomenon. The author therefore aims to establish the anatomical basis of recovery and its variability. The author studied 60 mental nerves on 30 lips. A total of 25 lips were studied in situ, including five receiving an intraarterial injection of latex, whereas five lips were removed and dissected under transillumination. The author identified three types of intralabial distribution of the mental nerves: type I, absence of connections; type II, connections on the upper third of the lower lip; and type III, connections on the upper, middle, and lower thirds of the lower lip. Some cases also had a dominant side with more numerous fibers and a larger diameter than the contralateral side. Rapid or total recovery after inferior alveolar nerve damage is well known. The author's study showed the nerve map to repair nerve damage, and for the first time, to the author's knowledge, it highlighted the connections between the mental nerves in the lip. Types II and III allow the recovery of labiomental sensation.