Retromolar foramen: an anatomical study with clinical considerations.

The retromolar canal and foramen, an anatomical variation in the mandibular retromolar area, houses and transmits neurovascular elements that may innervate the mandibular third molar and associated tissues. These structures have been implicated in local anaesthetic failure, loss of sensation in the normal distribution of the buccal nerve, and local haemorrhage during surgery. Examination of 885 dry mandibles showed that 70 had a retromolar foramen (8%). There were no significant differences between groups according to age, sex, or ancestry. The mean (SD) distance from molar to retromolar foramen was 16.8 (5.6) mm for the mandibular second molar and 10.5 (3.8) mm for the mandibular third molar. The link between these structures and failure of local anaesthesia seems tenuous at best. Bleeding may not represent a serious complication. Although there may be a possibility of perineural spread of infective and invasive pathology, we know of no reported cases. The only clear evidence of complications associated with a confirmed retromolar foramen seems to be loss of sensation in the normal distribution of the buccal nerve. Even though the retromolar foramen does not seem to be of great clinical importance, it could be a source of anxiety for the inexperienced practitioner.