The Oral Cavity - Lips and Vestibule

The Oral Cavity - Lips

• The lips are fleshy folds surrounding the oral opening.
• Externally, they are covered in skin.
• Internally, they are lined with mucous membrane.
• The lips' substance includes the orbicularis oris muscle and radiating muscles.
• Labial blood vessels, including superior labial, submental, and inferior labial arteries, are present.
• Nerves, like the infraorbital (upper lip) and mental nerves (lower lip), supply sensation.
• Connective tissue and small salivary glands are also features.
• The philtrum is a vertical groove on the upper lip's surface.
• The lips meet laterally at the mouth's angles.
• A frenulum (labial frenulum) connects each lip to the gum.

The Oral Cavity - Vestibule

• The vestibule lies between the lips/cheeks and teeth/gums.
• It's a slit-like space that connects to the oral fissure.
• When the jaws are closed, it connects to the mouth behind the third molar.
• The vestibule's lateral wall is formed by the buccinator muscle.
• The buccinator muscle, covered by mucous membrane, is tethered by elastic fibers.
• The mucous membrane of the gums (gingiva) is attached to the alveolar periosteum.
• The parotid salivary duct opens into the vestibule opposite the upper second molar.
• The mucous membrane forms folds called frenula from the lips to the gums.

The Oral Cavity - Cheeks

• Cheeks form the sides of the face.
• Cheeks are continuous with the lips.
• The nasolabial sulcus (furrow) marks the junction between cheeks and lips.
• Each cheek’s composition includes skin, superficial facial muscles, parotid duct, mucous glands, blood vessels, and nerves (e.g., maxillary and mandibular divisions).
• The buccinator muscle is covered by buccopharyngeal fascia and has a parotid duct.

The Oral Cavity - Gums

• Gums (gingivae) surround tooth necks and alveolar processes.
• They consist of fibrous tissue covered by stratified squamous epithelium.
• The gum has a free part (like a collar around the tooth) and an attached part firmly fixed to the jaw's alveolar arch.
• The gum tissue is continuous with periosteum around alveolar bone.
• Upper gums have nerves from the posterior, middle, and anterior superior alveolar nerves (maxillary nerve).
• Lower gums have nerves from the buccal branches of the mandibular and incisive nerves.
• Additional nerves include the lingual nerve and incisive branch of mental nerve.

The Oral Cavity - Lymphatics

• Upper gum lymphatics drain to submandibular nodes.
• Lower gum anterior lymphatics drain to submental nodes.
• Posterior lower gum lymphatics drain to submandibular nodes.

The Oral Cavity - Mouth Proper

• The hard palate forms the roof and the soft palate is behind it.
• The anterior two-thirds of the tongue and the reflection of the mucous membrane from the sides of the tongue largely form the oral floor.
• A midline fold (frenulum of the tongue) connects the tongue’s undersurface to the oral floor.
• The submandibular duct opens onto the floor of the mouth beside the frenulum.

The Oral Cavity - Sensory Innervation

• Roof: Greater palatine and nasopalatine nerves (maxillary division).
• Floor: Lingual nerve (mandibular division).
• Cheeks: Buccal nerve (mandibular division).
• Note: Buccal branch of facial nerve innervates buccinator muscle, whereas buccal nerve supplies cheek sensory.

The Oral Cavity - Palate

• The palate forms the roof of the oral cavity and floor of the nasal cavity.
• It has two parts: hard palate and soft palate.
• The hard palate is made up of maxillae's palatine processes and horizontal palatine bones.
• The greater and lesser palatine nerves emerge from the maxillary division (trigeminal).
• The greater palatine nerve innervates the hard palate.
• The lesser palatine nerve innervates the soft palate.
• Nasopalatine nerve innervates the anterior hard palate

The Oral Cavity - Soft Palate

• The soft palate is a mobile fold attached to the hard palate's posterior border.
• It includes the uvula, a projection in the midline.
• The soft palate's muscles (tensor veli palatini, levator veli palatini, and others) change its shape.

The Oral Cavity - Palatoglossal Arch

• A mucous fold that connects the soft palate to the tongue's side.

The Oral Cavity - Palatopharyngeal Arch

• A mucous fold behind the palatoglossal arch, attaching to the pharyngeal wall.
• Palatine tonsils are between the two arches.

The Oral Cavity - Palate - Blood Supply

• The greater palatine branch of the maxillary artery, ascending palatine branches of the facial artery, and ascending pharyngeal artery supply the palate.

The Oral Cavity - Palate - Nerve Supply

• The greater and lesser palatine nerves from the maxillary division innervate the palate via the greater and lesser palatine foramina.
• The greater palatine nerve serves the hard palate.
• The lesser palatine nerve serves the soft palate.
• Additional supply from a branch of the glossopharyngeal nerve (IX).

Explore the anatomy of the lips and vestibule in the oral cavity. This quiz covers the structure, blood supply, innervation, and significant features of these important areas. Perfect for students of anatomy and oral health!