Fig. 3From: Quantitative analysis of the relationship between maxillary incisors and the incisive canal by cone-beam computed tomography in an adult Japanese populationDefinitions of the three vertical levels in the midsagittal plane. n, r, and o, levels of the nasal opening of the incisive canal, root apex of the maxillary incisor, and oral opening of the incisive canal, respectively. P palatal planeBack to article page