16. Oral cavity. Proper oral cavity. Hard palate, soft palate, oral diaphragm, oropharyngeal isthmus. Macroscopic and microscopic characteristics. Blood and nerve supply.

Boundaries:

• Ventrally: lips
• Laterally: cheeks
• Floor: oral diaphragm
• Roof: palate
• Dorsally: continuous with the pharanyx

• The dental arches divide the oral cavity into the:

1. the oral vestibule
2. the oral cavity proper

The oral cavity proper

Borders:

• Anterior and lateral:
• Alveolar processes
• Gum
• Superior border: (concave)
• Hard palate
• Soft palate
• Inferior border:
• Tongue
• Mylohyoid m., Ant. belly of digastric m., Geniohyoid m.
• Posterior border: Continuous into the pharynx through oropharyngeal isthmus.

The oral vestibule:

• External borders:
• lips: 2 fleshy folds surrounding the oral orifice they accommodate orbicularis oris muscle. they contain nerves, vessels & glands.
• cheeks: they are continuous with lips at nasolabial grooves.
• Their muscle is buccinator
• Internally they are lined by mucos membrane.
• Externally they are covered by skin, buccal pad of fat, and buccopharyngeal fascia

• Internal borders:
• Teeth
• Gums

The vestibule contains the following:

1. Opening of the parotid duct.
2. Superior labia frenulum

• connect sup. lip to the gum

3. Inferior labia frenulum.
4. Maxillary tuberosity
5. Fornix