This investigation was performed to define the anatomical position of the mandibular canal and thus the neurovascular bundle in relation to mandibular anatomy and to relate the findings to the sagittal split osteotomy. The mandibles of 45 adult Asians were used. The superior-inferior and mediolateral course of the mandibular canal from the mandibular foramen to the mental foramen was measured at five specific cross-sectional locations. The results indicated that the safest location for performing the vertical corticotomy through the buccal plate is in the first and second molar area, as this is where the greatest distance between the corrical plate and the mandibular canal is found.