Comprehensive notes on the Oral Cavity: Morphology and Anatomy

ORAL CAVITY: Morphology and Physiology

  • Presenter/author: DR. SAM AFLORO-VIZCONDE, MEM; ADAM (as per slides)

Oral Anatomy: Definition and Scope

  • Oral anatomy is the study of the stomatognathic system, including:

    • The tooth, its parts, structure, form, and arrangements

    • Surrounding structures such as the periodontium, muscles, blood supply, lymph, nerve supply, the TMJ, and the glands

Learning Outcomes (module goals)

  • After completing the module, you should be able to:

    • Identify the structures inside the oral cavity and those associated with it

    • Appreciate the significance and role of each structure in maintaining a balanced stomatognathic system

    • Understand the interrelationship of every structure inside and associated with the stomatognathic system

    • Differentiate between normal and abnormal structures

Definition: Boundaries of the Oral Cavity

  • The oral cavity houses the sense organ for taste and the teeth

  • Schwarzrock definition: a space bounded by

    • Anteriorly – the lips

    • Laterally – the cheeks

    • Inferiorly – the floor of the mouth

    • Posteriorly – the pharynx

Major Divisions of the Oral Cavity

  • Oral Vestibule (Vestibularis Oris)

    • Space bounded laterally by the lips and cheeks

    • Medially by the alveolar process and the teeth

  • Oral Cavity Proper

    • Space within the arches of the teeth

    • Contains the tongue

Structures Inside the Oral Vestibule

  • Vestibular fornix

    • Horseshoe-shaped furrow; reflection of the mucous membrane between the roots/boundaries of lips, cheeks, and alveolar process

    • Function: permits mobility of lips and cheeks

  • Alveolar mucosa (covering the alveolar process)

    • Alveolar process: bone underlying the teeth

    • Alveolar mucosa: peripheral mucosal zone adjacent to the fornix; covers the alveolar process

    • Texture: more delicate; dark red and smooth; some mobility

  • Gingiva (gum tissue)

    • Firm and immovable; attached to bone and teeth

    • Pinkish in color; possesses stippling (pinpoint depessions)

Parts of the Gingiva

  • Marginal/Free gingiva: forms the gingival crevice between the cervix and the gingiva

  • Interdental papilla: tent-like or V-shaped structure occupying the interdental space

  • Attached gingiva: firmly attached to bone; where stippling is found

  • Mucogingival junction: sharp scalloped line separating alveolar mucosa and gingiva

  • Interproximal/Interdental gingiva: the gingiva between adjacent teeth

  • Labial Frenum: sagittal fold in the midline connecting the alveolar process with the lips; present in both upper and lower arches; typically sickle-shaped

  • Buccal Frenae: folds at the buccal aspect connecting the alveolar process and the cheek

Alveolar Alveolar/Mucosa Nomenclature (within the vestibule)

  • A: Alveolar Mucosa

  • B: Attached Gingiva

  • C: Mucogingival Junction

  • D: Free Gingival Groove

  • E: Free Gingiva

  • F: Interproximal/Interdental gingiva

Oral Cavity Proper: Teeth and Surroundings

  • The oral cavity proper contains:

    • The teeth arranged in two dental arches: the maxilla (upper arch) and the mandible (lower arch)

    • Teeth: central incisor, lateral incisor, canine, premolars, and molars (both arches)

  • Additional facial/labial features: superior lip, inferior lip; labial/buccal regions and associated frenula

  • Palatine structures: palatine raphe, palatoglossal arch; palato-hard palate; oropharynx; soft palate; uvula; palatine tonsil

  • Tongue and ductal features: tongue, duct of lingual (linguae), sublingual papilla

  • Glands: submandibular and sublingual glands

Structures of the Oral Cavity Proper: Maxilla (Upper Jaw) Mucous Membranes

  • Alveolar tubercle / maxillary tuberosity

    • A rounded bony protuberance posterior to the alveolar process

    • Covered by gingival tissue

  • Retroalveolar notch / hamular notch

    • A deep groove at the junction of the maxilla and palatine bone at the lower end of the pterygoid muscle

  • Retromolar papilla

    • A gingival elevation behind the last molar

Structures of the Oral Cavity Proper: Mandible (Lower Jaw) Mucous Membranes

  • Retromolar papilla: gingival elevation behind the last molar

  • Retromolar pad: an aggregate of buccal glands seen behind and above the retromolar papilla

  • Masseteric groove: a tissue depression just buccal to the retromolar pad; where fibers of the masseter muscle insert

  • Buccal shelf: hard, dense bone area buccal to the posterior teeth

Roof of the Oral Cavity Proper

  • The roof is formed by the palate and separates the oral cavity from the nasal cavity

  • Hard palate

    • Bony, comprising the palatine processes of the maxilla and the transverse process of the palatine bone

    • The right and left palatal halves meet at the midline at the intermaxillary suture

    • Epithelium is keratinized; pale pink with bluish-gray hue

  • Incisive papilla

    • An oval or pear-shaped prominence over the oral opening of the nasopalatine vessels

  • Incisive fossa

    • Opening through which nasopalatine vessels pass; visible beneath the incisive papilla

  • Median Palatine Raphe

    • A sharp but low ridge along the midline extending from the incisive papilla to the hard palate length

  • Transverse Palatine Raphe / Palatal Rugae

    • Irregular ridges radiating from the incisive papilla

Posterior Roof: Soft Palate, Fovea Palatinae, and Vibrating Line

  • Soft palate

    • Thick fold of mucous membrane with mucous glands; highly vascular; reddish in color

  • Fovea palatinae (palatine fovea of Steida)

    • Two pinpoint depressions where duct openings of palatine glands occur

  • Vibrating line (The Aah line)

    • Imaginary line posterior to the fovea palatinae; observed clinically when the patient says “ah”

Posterior Wall of the Oral Cavity

  • Pterygomandibular raphe

    • Tendinous band of mucous membrane stretching from the hamulus region of the pterygoid process toward the retromolar pad

    • Marks the posterior boundary of the oral cavity

Uvula and Fauces

  • Uvula

    • Bell-shaped mass at the midline, posterior to the soft palate; continuous with the soft palate

    • It helps prevent food from entering the nasal cavity by closing the nasopharyngeal opening during swallowing

  • Two Pillars of Fauces

    • Palatopharyngeal fold: the posterior border of the soft palate; forms the posterior pillar of the fauces

    • Palatoglossal fold: the anterior fauces; extends downward and laterally from the soft palate to the tongue; guards the tonsillar niche (a narrow, high, triangular-shaped fossa between the pillars containing the palatine tonsils)

Floor of the Mouth

  • Inferior boundary of the oral cavity

  • Mucosa is smooth and non-keratinized except for sublingual ridges and salivary eminences

  • Very vascular

  • Contains the submandibular and sublingual glands

Alveololingual Sulcus and Related Spaces

  • Alveololingual sulcus: space between the tongue and the alveolar process; horseshoe-shaped around the tongue

  • Three spaces of the alveololingual sulcus:

    • Premylohyoid space: shallow space from the incisors up to the canine region

    • Mylohyoid space: space from the first premolar up to the middle area of the second molar

    • Retromylohyoid space: space distal to the second molar down to the third molar; the deepest space

Lingual Structures of the Floor of the Mouth

  • Lingual frenum: tissue fold attaching the tongue to the floor of the mouth

  • Salivary/sublingual eminence: flat prominent eminence containing the sublingual gland

  • Sublingual fold: delicate fold along the crest of the eminence

  • Salivary caruncula (caruncle): a small papilla in the midline under the tongue

Summary Nomenclature (A–D)

  • A: Lingual Frenulum

  • B: Salivary Caruncula / Caruncle

  • C: Salivary Folds

  • D: Salivary Eminences