The Oral Cavity

Dr. Muznah Sultan LecturerDept. of Oral Biology

DIDC-DOW

The oral cavity is conveniently divided by the arch formed by the teeth and

gums into:

1. Oral Vestibule- lies between the gums and the teeth.

2. Oral Cavity Proper- lies behind and within the arch of teeth.

The Oral Vestibule

Boundaries:1. Anteriorly: the lips,2. Laterally: the

cheeks,3. Superiorly: the

mucolabial and mucobuccal folds, and

4. Posteriorly and medially: the teeth and gums.

The Oral Cavity Proper

Boundaries:1. Anteriorly and

laterally: the teeth and gums,

2. Superiorly:the palate (hard and soft),

3. Inferiorly: the tongue and the floor of the mouth

4. Posteriorly: the opening into the pharynx.

The Sublingual Region

Characteristic features:

1. Anterior 2/3 of the tongue,

2. Lingual frenulum,

3. Lingual vein,

4. Sublingual caruncle,

5. Sublingual folds

Gums and Gingivae- consist of dense vascular fibrous

tissue which is covered by mucous membrane and is attached to the alveolar margins of the jaw.

- they are continuous with the mucosa of the oral vestibule externally and the palate or the floor of the mouth internally.

Hard and Soft Palate

The palate forms the superior wall or the roof of the oral cavity proper. It is composed of the hard palate which has an osseous base, and behind, a soft palate composed of fibrous tissue.

The Hard Palate

- Covered by mucoperiosteum and forms a partition between the oral and nasal cavities.

- mucoperiosteum is thin in the middle but thicker at the sides due to the presence of numerous glands

- formed by the palatine process of the maxilla and the horizontal plate of the palatine bone.

The Soft Palate

Is the posterior movable portion of the palate, extending from one side of the pharynx to the other, and attached to the posterior border of the hard palate.

Muscles of the Soft PalateMuscle Origin Insertion Action

Palatopharyn-geus

Palatal aponeurosis

Lateral wall of the pharynx and posterior border of the thyroid cartilage

Elevates the pharynx and larynxCloses the oropharyngeal isthmus

Palatoglossus

Palatal aponeurosis

Dorsum and lateral aspect of the tongue

Closes the oropharyngeal isthmus

Uvular Posterior nasal spine

Uvula Raises the uvula to help seal oral from nasal pharynx

Muscles of the Soft Palate

Muscle Origin Insertion Action

Levator veli palatini

Medial aspect of the auditory tube

Directly into the palatine aponeurosis

Elevates palate during swallowing, yawning

Tensor veli palatini

Lateral aspect of the membranous portion of the auditory tube, scaphoid fossa of the sphenoid bone

Tendon hooks under hamulus and inserts into the palatal aponeurosis

Tenses the palate and opens the mouth of auditory tube during swallowing and yawning

The Tongue

OA mobile mass of muscles lying on the floor of the mouth and associated with the function of taste, chewing, swallowing, and speaking.

Characteristic features:

1. Root is the lower portion of the posterior half of the tongue through which the extrinsic muscles, blood vessels and nerves become connected with the organ. It is attached to the mandible and the hyoid bone

2. Body anterior part of the tongue, made up of interlacing skeletal muscles.

3. Margins are the lateral portion of the tongue, free and blunt, in relation to the gums and teeth.

4. Tip or apex is the pointed and free anterior end.

5. Inferior surface is seen when the tongue is turned upwards.

The Lingual Papillae

1. Vallate or circumvallate papillae are the largest, numbering from 7-12, and are arranged in front of the sulcus terminalis.

2. Fungiform papillae are fewer in number and are limited to the tip and margins of the tongue.

3. Filiform papillae are the smallest and the most numerous, scattered all over the anterior 2/3 of the dorsum of the tongue.

The Taste Buds- are receptor organs for the special sensation of taste. They are pale oval bodies most of which are located surrounding the vallate papillae; a few are found on the fungiform and foliate papillae. A few taste buds are scattered through the epithelium of the oral surface of the soft palate, the posterior wall of the pharynx, and the epiglottis.

The Muscles of the TongueExtrinsic muscles are responsible for

changing position of the tongue.Muscle Origin Insertion Action

Genioglossus Genial tubercle of mandible

Tongue Retract and depress the tongue

Hyoglossus Hyoid bone Posterior half of the side of the tongue

Depress the tongue

Styloglossus Styloid process of temporal bone

Whole length of the tongue

Pull the tongue upwards and backwards

The Muscles of the Tongue

The Intrinsic Muscles:1. Superior and inferior longitudinal

muscles- Located close to the dorsum of the

tongue- Shorten the length of the tongue

and to curl the tip of the tongue and back.

2. Transverse muscles- narrows the tongue.

3. Vertical muscles- flattens the tongue.

A Summary of the Actions of the Tongue

1. Protrussion : genioglossus2. Retrussion : hyoglossus,

styloglossus, genioglossus3. Depression : genioglossus,

hyoglossus4. Elevation : styloglossus

Tongue TieA large lingual frenulum can limit the

mobility of the tongue and interfere with speech. The condition is easily repaired by cutting the frenulum (lingual frenectomy).

The Salivary Glands and

Accessory Glands of the Oral Cavity

The Salivary Glands of the Oral Cavity

1. Parotid Gland

2. Submandibular Gland

3. Sublingual Gland

The Accessory Glands

Beside the main salivary glands, many others exists: some in the tongue, others around and in the palatine tonsil between its crypts, with the large number in the soft palate, the posterior part of the hard palate, the lips and the cheeks. These are similar in structure to larger salivary glands and are mainly mucous type.

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