In the adult dogs, the distances from the root of premolar tooth to infra-orbital canal and from the latter to the root of the canine tooth were 1.07 cm and 3.4 cm, respectively. It had been demonstrated that the infra-orbital foramen in the skull of dog is over the alveolus for the third premolar tooth and infra-orbital nerve emerges through this foramen [5]. Therefore, these data can be useful for tracking the infra-orbital nerve and necessary for the desensitization of the skin of the upper lip, nostril and face on that side of the level of the foramen [5]. The injection of local anesthetic agents within the canal via the infra-orbital foramen will also lead to analgesia of the incisor, canine and first three premolars. In the present study, the distance from the lateral alveolar root to mental foramen was 2.3 cm. This parameter is a vital guide that will detect the location of the mental nerve for this regional nerve block in the adult dogs; especially for lower lip anesthesia. The injection of the local anesthetic agents can be made in the rostral aspect of the mandibular canal through the mental foramen to mandibular nerve block in the mental zone. This will ensure the loss of sensation of the lower incisors, premolar and lower lip on the same side [9] during lower lip trauma, dental extraction and treatment of the tooth injuries.