Boundaries:
- Ventrally: lips
- Laterally: cheeks
- Floor: oral diaphragm
- Roof: palate
- Dorsally: continuous with the pharanyx
- The dental arches divide the oral cavity into the:
- the oral vestibule
- 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:
- Opening of the parotid duct.
- Superior labia frenulum
- connect sup. lip to the gum
- Inferior labia frenulum.
- Maxillary tuberosity
- Fornix