Oral Landmarks and Anatomy

ORAL LANDMARKS

Lips

  • Labium superius (Superior labialis): The upper lip.
  • Labium inferius (Inferior labialis): The lower lip.
  • Lateral commissure: Junction of the upper and lower lips at the corners of the mouth.

Vermillion Region

  • Vermillion Border: A normally sharp demarcation between the red of the lip and the adjacent normal skin.
  • Vermillion Zone: The red area of the lip, covered by a stratified squamous keratinized epithelium. This area lacks sweat and oil glands, which is why lips need to be moisturized.
  • Philtrum: A midline vertical depression of the skin between the nose and upper lip.

Oral Cavity

  • The oral cavity is divided into two main areas:
    • Vestibule: The space or potential space that exists between the lips or cheeks and the teeth.
    • Oral Cavity Proper: The area surrounded by the teeth or alveolar ridges, extending back to the palatine tonsils. It includes the region from the floor of the mouth upward to the hard and soft palates.
Components of the Oral Cavity Proper
  • Hard Palate:
    • A thin horizontal bony plate of the skull that forms the roof of the mouth, spanning the arch formed by the upper teeth.
    • Palatine Rugae: Transverse ridges of epithelial and connective tissue on the hard palate.
    • Palatine Raphe: A hard linear elevation along the midline of the hard palate, marking the external manifestation of the palatine suture.
  • Incisive Papilla: A singular bulge of tissue at the midline, located immediately posterior to the central incisors (teeth 8 & 9). The incisive foramen beneath carries the nasopalatine nerves and blood vessels to the mucous membrane lingual to the maxillary incisors.
  • Maxillary Torus: An excess bone growth located in the midline of the hard palate.

Soft Palate

  • Soft Palate: Composed of soft tissue, this area is the back of the roof of the mouth and does not contain bone.
  • Uvula: A downward-projecting muscle located in the posterior portion of the soft palate at the midline.
  • Anterior Pillars or Glossopalatine Arch: Thin folds of epithelium extending laterally and inferiorly from both sides of the soft palate to the base of the tongue.
  • Posterior Pillar or Pharyngopalatine Arch: A thin fold of epithelium that is more posterior and narrower than the anterior arch.
  • Tonsillar Recess: A recessed area between the anterior and posterior arches, housing the palatine tonsils (globules of lymphoid tissue).

Additional Oral Landmarks

  • Retromolar Pad: A triangular area of bone and tissue distal to the last mandibular molar.
  • Maxillary Tuberosity: A protuberance of alveolar bone distal to the last maxillary molar.
  • Palatine Fovea: Small dimples on either side of the midline at the junction of the hard and soft palates, formed by the coalescence of several mucous gland ducts.

Other Key Features

  • Fordyce Glands/Spots:
    • Found on the inner aspect of the upper lip.
    • Represent trapped sebaceous glands; appear as submucosal yellowish, pin-head sized papular lesions, often clustered together.
  • Buccal Mucosa: Mucosal membrane lining the inner cheek.
  • Alveolar Mucosa: A thin, movable mucosal lining covering the alveolar bone.
  • Buccal Frenum: Folds of epithelium located between the cheek and attached gingiva in the first premolar area.
  • Attached Gingiva: Keratinized tissue firmly attached to the alveolar bone, separated from the alveolar mucosa by the mucogingival junction (a scalloped line) that demarcates the attached gingiva from the alveolar mucosa.

Lingual Features

  • Floor of the Mouth: Contains several key structures:
    • Plica Fimbriata: Fringe-like projections on the undersurface of the tongue, lateral to the lingual vein.
    • Lingual Vein: Blue line on the undersurface of the tongue, located on either side of the lingual frenum.
    • Lingual Frenum: A thin fold of epithelium attaching the underside of the tongue to the floor of the mouth.
    • Sublingual Caruncle: Small elevation at the base of the lingual frenum, serving as an opening for the ducts of two major salivary glands (Wharton's Duct).
    • Sublingual Fold: A fold of tissue extending from the sublingual caruncle along the floor of the mouth.
  • Mandibular Tori: Bony swellings on the lingual surface of the mandible, often located in the canine area.

Oral Pathologies

  • Cheilosis: A painful condition manifesting as blisters or cracks at the corners of the mouth, often due to diet deficiencies (e.g., Vitamin B12).
  • Cleft Lip:
    • Unilateral Incomplete: A small separation on one side of the lip.
    • Unilateral Complete: A complete separation on one side of the lip.
    • Bilateral Complete: A complete separation on both sides of the lip.
  • Vesicle: A liquid-filled cavity under the epidermis commonly referred to as a blister.
  • Abnormal Frenum Attachment: High frenum attachment may affect dental development, necessitating surgical intervention to allow better positioning of permanent teeth.

Tongue Anatomy and Dysfunction

  • Tongue: Composed of a large bundle of skeletal muscles that manipulates food during chewing and swallowing (deglutition).
  • Papillae Types:
    • Foliate Papillae: Vertical ridges on the lateral borders of the tongue containing taste receptors.
    • Filliform Papillae: Fringelike, keratinized projections found in the middle third of the dorsum of the tongue.
    • Fungiform Papillae: Mushroom-shaped, red to dark brown elevations scattered over the anterior third of the dorsum of the tongue.
    • Circumvallate Papillae: 8-10 large papillae arranged in an inverted V at the posterior position of the tongue.
  • Plica Fimbriata and Lingual Vein: Features on the underside of the tongue integral to its structure.

Diseases and Conditions of the Oral Cavity

  1. Fissured Tongue: Characterized by folds and fissures on the dorsal surface of the tongue.
  2. Median Rhomboid Glossitis: Considered normal anatomy but can present as a discrete, red,