Incidence of large accessory mandibular foramen in human mandibles

The mandibular foramen (MF) is present on the inner surface of the ramus of the mandible. The inferior neurovascular bundle passes through it. A large accessory mandibular foramen (AMF) was present postero-superior to the normal MF (left side) in 1 mandible out of 335 (0.3%) mandibles observed. The diameters of this foramen were 10 mm antero-posteriorly and 5 mm vertically, and that of MF were 7 mm antero-posteriorly and 5 mm vertically. The distance between these 2 foramina was 11 mm, and between the AMF and the apex of the lingula was 4 mm. The distances from the posterior limit of AMF to the posterior border of the ramus and angle were 18 mm and 52 mm, respectively. The AMF led into a canal that passed obliquely forwards and lateral to the mandibular canal and joined the latter at the level of the 3^rd molar. A large AMF is a rare occurrence and therefore one should be aware of its incidence, since the structure/s passing through it could be compromised during surgical procedures of this area.