Fig. 2. The course of the mandibular canal, with the absence or presence of an anterior loop. A. The incisive canal and its corresponding image in the coronal reconstruction, with a diameter that must be less than 3 mm. B. The anterior loop and its corresponding image in the coronal reconstruction, which, depending on the place it is obtained, can be represented by a round hypodense area with a diameter of at least 3 mm or by two round hypodense areas.