Development of the lips and palate.

1. Development of the lips and palate. V VII IX X V1 V2 V3 Dr. Frank C. T. Voon 13 Apr 2009

2. Summary The mandible and lower lip are formed by the fusion of the paired mandibular processes. The upper lip develops from the intermaxillary segment and from fusion of the maxillary process with the medial nasal process on each side. The intermaxillary segment gives rise to the philtrum, incisors and the primary palate. The secondary palate develops from fusion of the palatine shelves of the maxillary process.

3. Medial nasal processes Maxillary processes Intermaxillary segment labial component philtrum Lip - lateral part Lip - median part alveolar component 4 incisors palatal component Palatine shelves primary palate Concept Hard palate Maxilla & Palatine bone secondary palate Definitive palate Soft palate muscles

4. Derivatives of the Germ Layers Epithelium Nerve Connective tissue Muscle Endoderm Ectoderm Mesoderm

5. The face begins to form in the 4th week. Brain 3rd The mesenchyme (mesoderm) of 5 facial primordia from the 1st pharyngeal arch proliferate around the stomodeum. 2nd 1st Heart Liver

6. The 5 facial primordia are the: single frontonasal process, paired maxillary processes, and paired mandibular processes. Cardiac bulge

7. Medial and lateral nasal swellingsalso form as part of the frontonasal process. The right and left medial nasal swellings fuse to form the intermaxillary segment.

8. The intermaxillary segment develops into 3 parts, the philtrum, the alveolar part (4 incisors) and the primary palate. The maxillary and medial nasal process on each side fuse to form the rest of the upper lip. The right and left mandibular processes fuse to form the mandible. Maxillary process Mandibular processes

9. The palatine shelves of the right and left maxillary processes fuse with the primary palate to form the definitive palate. Philtrum 4 incisors Primary palate Secondary palate The incisive foramen marks the point of fusion between the two palatine shelves with the intermaxillary segment.

10. Cleft lip & palate Cleft secondary palate unilateral bilateral

11. In the adult, the definitive palate consists of the hard palate and soft palate as well. The palatine process of the maxilla and the horizontal plate of the palatine bone are the bones of the hard palate. The soft palate contains 5 muscles, namely the: Palatoglossus, Palatopharyngeus, Musculusuvulae Levatorvelipalatini, & Tensor velipalatini. Palatoglossus, palatopharyngeus, musculusuvulae and levatorpalati are supplied by the branches of the vagus nerve in the pharyngeal plexus. Tensor palati is supplied by the mandibular nerve.

12. The Palate The palate consists of the hard palate and soft palate. The hard palate separates the oral cavity from the nasal cavity. The softpalate separates the oropharynxfrom the nasopharynx . The 3 foramina in the hard palate are the: incisive foramen which transmits the nasopalatine nerve and artery, greater palatine foramen which transmits the greater palatine n & a., lesser palatine foramen which transmits the lesser palatine n & a. The mucosa of the hard palate is supplied by thenasopalatine and greater palatine nerves. The mucosa of the soft palate is supplied by the lesser palatine nerves. These are all branches of the maxillary nerve. The mucous glands are supplied by parasympathetic fibers from the pterygopalatineganglion. There are taste fibers in the soft palate which travel with the lesser palatine nerves, pass through the pterygopalatinefossa and pterygoid canal, and then travel with the greater petrosal nerve to join the facial nerve, and their cell bodies are in the geniculate ganglion.