anterior nasal spine การใช้

• It includes complete total absence of the anterior nasal spine.
• This process joins with that on the opposite side to form the anterior nasal spine.
• The anterior nasal spine is the thin projection of bone at the midline on the lower nasal margin, holding the cartilaginous center of the nose.
• The front part of this ridge rises to a considerable height, and is named the incisor crest; it is prolonged forward into a sharp process, which forms, together with a similar process of the opposite bone, the anterior nasal spine.
• Medially, the anterior surface of the maxilla is limited by a deep concavity, the nasal notch, the margin of which gives attachment to the dilator naris posterior and ends below in a pointed process, which with its fellow of the opposite side forms the anterior nasal spine.
• It is bounded above by the inferior borders of the nasal bones; laterally by the thin, sharp margins which separate the anterior from the nasal surfaces of the maxilla; and below by the same borders, where they curve medialward to join each other at the anterior nasal spine.
• The small part in front of this suture constitutes the premaxilla ( " os incisivum " ), which in most vertebrates forms an independent bone; it includes the whole thickness of the alveolus, the corresponding part of the floor of the nose and the anterior nasal spine, and contains the sockets of the incisor teeth.