Читать книгу Feline Dentistry - Jan Bellows - Страница 34

The maxillary bones (maxillae) form the lateral parts of the face and the part of the hard palate that houses the canines and upper cheek teeth. The maxilla articulates with the incisive bone rostrally, the nasal bone dorsally, the vomer bone medially, and the lacrimal and zygomatic bones caudally (Figure 1.13a,b). The maxillae extend to the caudal border of the hard palate laterally and are joined medially by the paired palatine bones to complete the hard palate. The infraorbital canal is located apical to both the maxillary third and fourth premolars below the orbit.

The palatine bone forms the bony part of the hard palate together with the maxillary and incisive bones. The incisive bone located rostrally houses the upper incisors and forms approximately one‐sixth of the hard palate. A pair of openings, the palatine fissures, allows passage of the incisive ducts to the vomeronasal organ. The incisive papilla located just caudal to the maxillary first incisor teeth houses these incisive ducts as they open into the oral cavity The ducts serve as a pathway for air to be drawn in, which is then directed over extensions of the vomeronasal apparatus in the floor of the nasal cavity immediately behind the palatine fissures (Figure 1.14a,b).

The hard palate separates the oral and nasal cavities. The primary palate is the incisive portion of the palate and associated soft tissues. The secondary palate includes the remaining hard and soft palatal structures. Firmly attached, heavily keratinized mucosa covers the hard palate. Seven to eight transverse ridges called rugae protrude from the mucosa with rows of papillae between the ridges. The soft palate begins caudal to the maxillary first molar teeth and separates the nasopharynx dorsally from the oropharynx ventrally.

Figure 1.13 (a) Lateral aspect of right maxilla: 1. Alveolar process; 2. Frontal process; 3. Infraorbital canal; 4. Zygomatic process. (b) Medial aspect of the right maxilla: 1. Maxillotubinates; 2. Palatine process.

The infraorbital canal is located apical to the maxillary third and fourth premolars below the orbit. Compared to the dog, the cat's infraorbital canal is shorter and usually less than five millimeters in diameter.

Figure 1.14 (a) Palatine fissures. (b) Incisive papilla.