Recent studies using cone-beam computer tomography (CBCT) have added to our understanding of anatomical variation in the mandible of humans. However, the distribution of nerves cannot be revealed by CBCT. There have been investigations of the distribution of nerves relating to the mandible, but some proposed causes of these variations remain controversial. In this study, we observed a total of 10 sides from five mandibles of Macaca fascicularis of unknown age and sex using CBCT and dissection under stereomicroscopy. Nine of the 10 sides had two mental foramina in each side. Innervation by the mental nerves depended on the locations of those foramina. The long branch to the mandibular angle ran with a branch of the facial artery, which joined the mental artery in all 10 sides. Five specimens had a median perforating canal in the mandibular bone. In addition, a branch of the sublingual artery, which joined with the small branches of the submental artery, entered the mandibular bone from the median lingual foramen. This foramen was located in the lower part of the mandibular symphysis and passed via the median perforating canal to exit from the median labial foramen, also located in the lower part of the mandibular symphysis. We speculate that the median perforating canal of the mandible, rarely found in humans, is the remnant of the feeding artery of the fetal mandible, and in M. fascicularis is seen in all specimens because they have no mental protuberance. Anat Rec, 300:1464-1471, 2017. © 2017 Wiley Periodicals, Inc.