Accessory mandibular foramina and bifid mandibular canals: An anatomical study

Bifid mandibular canals associated with accessory mandibular foramina are claimed to pose complications in oral surgery and allied procedures resulting in paraesthesia and haemorrhage, due to injury to the divisions of inferior alveolar nerves and vessels passing through them. Sometimes these nerves escape the effect of anaesthetics leading to difficult inferior alveolar nerve block. These variant canals serve as a source of spread of cancer from cortical to cancellous part of the mandible. The current descriptive study included thirty intact, dry, adult human mandibles. They were examined macroscopically to note the presence of accessory mandibular foramina and the accessory mandibular canals arising from them. These aberrant canals were probed and their length was noted. The probed mandibles were X-rayed to observe the course of these canals. The location of the foramina was determined from nearby anatomical landmarks.Six mandibles (20%) showed accessory mandibular foramina. The length of the accessory mandibular canals originating from the accessory mandibular foramina was found to vary from 0.9 cm to 4.5 cm. On X-ray films, the variant canals were noted to proceed towards third molar or towards the angle of mandible. Some of these canals merged with the main mandibular canal. The findings of the study will be helpful in oral surgery, radiology and cancer therapy.