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Oral Cavity
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Oral Cavity

Key functions of the Oral Cavity:
Initiates chemical and mechanical (aka, physical) digestion:
  • The teeth and tongue physically manipulate the food;
  • Salivary enzymes chemically digest carbohydrates.
Anatomical divisions
  • Oral vestibule
    • External to the teeth.
  • Oral cavity proper
    • Enclosed by the teeth.
Boundaries of the mouth:
  • Superiorly, the palate forms the roof of the mouth.
  • Inferiorly, the right and left mylohyoid muscles form the "floor" of the mouth; they extend from the mandible ("mylo") to the hyoid bone.
  • Anteriorly, the lips enclose and regulate the oral fissure (aka, opening).
  • Laterally, the cheeks comprise soft tissues (including muscles) that compress the walls of the mouth.
  • Posteriorly, the oral cavity is open to the oropharynx, which accepts the swallowed foods and liquids.
  • Internally, the oral mucosa lines the mouth.
Structures
  • Lips
    • Muscles, including the orbicularis oris and superior and inferior labial muscles
  • Neurovascular structures.
  • Teeth
- Housed in the maxilla and the lower teeth are housed in the mandible
  • Gingivae (aka, gums)
    • Cover the bones of the jaws and with overlying mucosal membrane;
  • Labial frenulum
    • Superior and inferior labial frenulum attach the gingivae to the lips.
  • Lingual frenulum
    • A mucosal fold that attaches the inferior surface of the tongue to the floor of the oral cavity
  • Extrinsic salivary glands
- Parotid gland is the largest, and lies in the side of the face, anterior to the ear and superficial to masseter; drains saliva into the mouth via the parotid duct. The parotid duct is easily visible during dissection, given its relatively large diameter and long length as it passes superficially over masseter.
    • Sublingual gland lies beneath the tongue in the floor of the mouth; secretes saliva across this lining via several small ducts. "Sublingual" refers to the gland's location below the tongue.
    • Submandibular gland lies along the medial side of the mandible and wraps around the mylohyoid muscle; its duct drains into the floor of the mouth.
  • Salivary duct orifices
    • Release saliva into the floor of the mouth via orifices under the anterior tongue.
  • Hard palate
    • Forms anterior 2/3rds of the palate
    • Comprises the maxillary and palatine bones
    • Palatine raphe is raised midline ridge that signifies where the right and left sides of the palate fused during fetal development
    • Transverse palatine folds aka, palatine rugae, are ridges of connective tissue that provide friction to faciliatate bolus formation.
  • Soft palate
    • Comprises the palatine aponeurosis (which attaches anteriorly to the hard palate) and 4 sets of paired muscles.
    • During swallowing, the soft palate raises to block foods and liquids from the posterior opening to the nasal cavity.
    • Uvula extends from the free edge of the soft palate at the midline; comprises the musculus uvulae and connective tissues.
  • Two posterior arches:
    • Palatoglossal arch extends from the soft palate to the tongue.
    • Palatopharyngeal arch attaches to the pharynx.
    • These arches are formed by the bilateral palatopharyngeus muscles, which elevate the pharynx during swallowing.
  • Palatine tonsils
    • Lie between the arches
    • Collections of lymphoid tissue housed within the tonsillar sinuses (aka, fossae); the palatine tonsils monitor and respond to ingested infectious materials.
  • Fauces
    • Posterior opening of the oral cavity; it leads to the oropharynx.

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