About 12 to 15 mm from the anterior nasal spine, and close to the septum, the incisive canal (6) occurs. Within the body of each maxilla the canal is directed slightly forward and toward the midline until they typically join into a common opening into the oral cavity, the incisive fossa (anterior palatine foramen).

The soft tissues of the nasal cavity differ from those of the paranasal sinuses in being thicker and more richly supplied with blood vessels, nerves, and glands. The vestibule, or entrance chamber lying in front of the inferior meatus, is lined with a continuation of the skin: stratified, squamous epithelium, guarded by hairs, and lubricated by sebaceous and sweat glands. As the soft tissues pass into the atrium, or beginning of the nose, they become firmly attached to the bone. Thus perforating the bone at this point almost surely guarantees piercing the soft tissues.

The relationships between the nasal cavity and the oral cavity interest the implantologist primarily in terms of the amount of bone separating the anterior extent of the cavity from the residual dental crest in the incisor region. Even when teeth are present, the amount of bone between the incisors and the fossae varies considerably. Two unrelated factors give the face its anterior height and determine the amount and shape of the support for the upper lip. These factors are the length of the tooth and the amount of bone between the apex of the root of the tooth and the floor of the nasal cavity. The central incisors (7) are always a little nearer the fossae than are the lateral incisors because the central incisors' roots are slightly longer and the fossae begin curving upward in the region of the lateral incisors.