2. The palate

3. The palate forms the roof of the mouth. It is divided into two parts: Anterior 2/3 (the hard palate) and posterior 1/3 (the soft palate). The Hard palate: –Is formed by the palatine process of the maxilla and the horizontal plate of the palatine bone. –It is bounded by the alveolar arches. –It forms the floor of the nasal cavity. –Posteriorly, it is continuous with the soft palate. –It is covered by dense fibrous tissue with a surface mucosal membrane –It has a median raphe –Its mucosal covering is thick and corrugated (smooth posteriorly) –The mucosa contains mucous palatine glands The palate forms the roof of the mouth. It is divided into two parts: Anterior 2/3 (the hard palate) and posterior 1/3 (the soft palate). The Hard palate: –Is formed by the palatine process of the maxilla and the horizontal plate of the palatine bone. –It is bounded by the alveolar arches. –It forms the floor of the nasal cavity. –Posteriorly, it is continuous with the soft palate. –It is covered by dense fibrous tissue with a surface mucosal membrane –It has a median raphe –Its mucosal covering is thick and corrugated (smooth posteriorly) –The mucosa contains mucous palatine glands

4. The Soft Palate It is a mobile fold attached to the posterior border of the hard palate and extends backwards and downwards between nasopharynx and oropharynx. The uvula is the midline conical projection from the posterior border of the soft palate. The soft palate is continuous laterally with pharyngeal wall. It is covered by mucosa which encloses: an aponeurosis, muscles, vessels, nerves and palatine glands. Two mucous folds extend laterally from the uvula to the pharynx: – Palatoglossal arch anteriorly (contains palatoglossus) – Palatopharyngeal arch posteriorly (contains palatopharyngeus) The 2 folds enclose the palatine tonsil It is a mobile fold attached to the posterior border of the hard palate and extends backwards and downwards between nasopharynx and oropharynx. The uvula is the midline conical projection from the posterior border of the soft palate. The soft palate is continuous laterally with pharyngeal wall. It is covered by mucosa which encloses: an aponeurosis, muscles, vessels, nerves and palatine glands. Two mucous folds extend laterally from the uvula to the pharynx: – Palatoglossal arch anteriorly (contains palatoglossus) – Palatopharyngeal arch posteriorly (contains palatopharyngeus) The 2 folds enclose the palatine tonsil

5. Tensor Palati Origin: 1. Spine of sphenoid 2. Scaphoid fossa 2. Scaphoid fossa 3. Outer wall of auditory tube 3. Outer wall of auditory tube Insertion: Palatine aponeurosis (the tendon hooks on the pterygoid hamulus). Nerve supply: Nerve to medial pterygoid from main trunk of mandibular nerve. Action: It tenses the soft palate. Origin: 1. Spine of sphenoid 2. Scaphoid fossa 2. Scaphoid fossa 3. Outer wall of auditory tube 3. Outer wall of auditory tube Insertion: Palatine aponeurosis (the tendon hooks on the pterygoid hamulus). Nerve supply: Nerve to medial pterygoid from main trunk of mandibular nerve. Action: It tenses the soft palate.

6. Levator Palati Origin: 1. Inferior surface of the petrous part of the temporal bone. part of the temporal bone. 2. Lower surface of auditory tube 2. Lower surface of auditory tube Insertion: Palatine aponeurosis. Nerve supply: Pharyngeal plexus (cranial part of accessory nerve). Action: It elevates the soft palate. Origin: 1. Inferior surface of the petrous part of the temporal bone. part of the temporal bone. 2. Lower surface of auditory tube 2. Lower surface of auditory tube Insertion: Palatine aponeurosis. Nerve supply: Pharyngeal plexus (cranial part of accessory nerve). Action: It elevates the soft palate.

7. Palatopharyngeus Muscle Origin: Palatine aponeurosis. Insertion: posterior border of thyroid cartilage and wall of the pharynx. Nerve supply: Pharyngeal plexus. Action: 1.It elevates the larynx during swallowing. 2.It pulls the palatopharyngeal arch medially to close the pharyngeal isthmus. Origin: Palatine aponeurosis. Insertion: posterior border of thyroid cartilage and wall of the pharynx. Nerve supply: Pharyngeal plexus. Action: 1.It elevates the larynx during swallowing. 2.It pulls the palatopharyngeal arch medially to close the pharyngeal isthmus.

8. Palatoglossus muscle Origin: palatine aponeurosis. Insertion: the side of the tongue. Nerve supply: pharyngeal plexus (cranial part of accessory nerve through the vagus nerve). Action: pulls the root of the tongue upward and backward to narrow the oropharyngeal isthmus. Origin: palatine aponeurosis. Insertion: the side of the tongue. Nerve supply: pharyngeal plexus (cranial part of accessory nerve through the vagus nerve). Action: pulls the root of the tongue upward and backward to narrow the oropharyngeal isthmus.

9. Musculus Uvulae Origin: Posterior nasal spine and palatine aponeurosis. Insertion: Mucous membrane of the uvula. Nerve supply: pharyngeal plexus (cranial part of accessory nerve through the vagus nerve). Action: elevation of the uvula. Origin: Posterior nasal spine and palatine aponeurosis. Insertion: Mucous membrane of the uvula. Nerve supply: pharyngeal plexus (cranial part of accessory nerve through the vagus nerve). Action: elevation of the uvula.

10. Nerve supply of the palate Sensory: 1. Greater palatine from sphenopalatine ganglion 2. Lesser palatine from sphenopalatine ganglion 3. Nasopalatine from sphenopalatine ganglion 4. Glossopharyngeal Motor: –All muscles of the palate are supplied by pharyngeal plexus (cranial part of accessory nerve through vagus) except tensor palati (supplied by mandibular nerve) Secretomotor: (to the palatine glands) –Postganglionic fibers from the sphenopalatine ganglion (carried by the lesser palatine nerve) Sensory: 1. Greater palatine from sphenopalatine ganglion 2. Lesser palatine from sphenopalatine ganglion 3. Nasopalatine from sphenopalatine ganglion 4. Glossopharyngeal Motor: –All muscles of the palate are supplied by pharyngeal plexus (cranial part of accessory nerve through vagus) except tensor palati (supplied by mandibular nerve) Secretomotor: (to the palatine glands) –Postganglionic fibers from the sphenopalatine ganglion (carried by the lesser palatine nerve)

11. Blood supply of the palate Arterial supply of the palate: 1. Greater palatine artery (from maxillary artery) 2. Lesser palatine arteries (from maxillary artery) 3. Ascending palatine artery (from facial artery) 4. Palatine branch of ascending pharyngeal artery. Arterial supply of the palate: 1. Greater palatine artery (from maxillary artery) 2. Lesser palatine arteries (from maxillary artery) 3. Ascending palatine artery (from facial artery) 4. Palatine branch of ascending pharyngeal artery. Lymph drainage of the palate To the deep cervical lymph nodes.

12. Function of the soft palate The soft palate is raised to close the pharyngeal isthmus during the following: –Swallowing, to prevent regurgitation of food and fluid into nasopharynx –Speech, to produce explosive sounds –Blowing, to prevent escape of air into the nasopharynx The soft palate is raised to close the pharyngeal isthmus during the following: –Swallowing, to prevent regurgitation of food and fluid into nasopharynx –Speech, to produce explosive sounds –Blowing, to prevent escape of air into the nasopharynx

13. Mechanism of swallowing

14. The First Stage It is a voluntary process. The tongue is raised up against the hard palate, from tip and extending backwards, driving the food bolus backwards The soft palate is pulled down The food bolus lies in a groove on the dorsum of the tongue More pressure of the dorsal surface against the hard palate pushes the bolus backwards into oropharynx It is a voluntary process. The tongue is raised up against the hard palate, from tip and extending backwards, driving the food bolus backwards The soft palate is pulled down The food bolus lies in a groove on the dorsum of the tongue More pressure of the dorsal surface against the hard palate pushes the bolus backwards into oropharynx

15. The Second Stage It is involuntary process. Soft palate is raised up and makes contact with the posterior pharyngeal wall closing off the pharyngeal isthmus Hyoid bone and larynx are raised up and forwards. The epiglottis is tipped down closing the laryngeal inlet (but not completely) Approximation of the aryepiglottic folds prevents entry of food into larynx A stripping wave moves down the pharyngeal wall pushing the food bolus down The soft palate is pulled down, approximated to the tongue and pressed against it by the stripping wave, thus the oropharyngeal isthmus is closed off It is involuntary process. Soft palate is raised up and makes contact with the posterior pharyngeal wall closing off the pharyngeal isthmus Hyoid bone and larynx are raised up and forwards. The epiglottis is tipped down closing the laryngeal inlet (but not completely) Approximation of the aryepiglottic folds prevents entry of food into larynx A stripping wave moves down the pharyngeal wall pushing the food bolus down The soft palate is pulled down, approximated to the tongue and pressed against it by the stripping wave, thus the oropharyngeal isthmus is closed off

16. The Third Stage It is involuntary process. The thyropharyngeus part of inferior constrictor contracts, while the cricopharyngeus relaxes pushing the bolus down the esophagus Failure of relaxation of cricopharyngeus leads to herniation of the mucosa between thyro- and cricopharyngeus forming a small pharyngeal pouch. It is involuntary process. The thyropharyngeus part of inferior constrictor contracts, while the cricopharyngeus relaxes pushing the bolus down the esophagus Failure of relaxation of cricopharyngeus leads to herniation of the mucosa between thyro- and cricopharyngeus forming a small pharyngeal pouch.