Oral Cavity

Introduction

  • 30% of head and neck region tumors
  • 3% of all cancers
  • For all stages 5-year relative survival —> 59%
    • 10-year survival —> 44%
  • Prognostic factors:
    • Presence of lymph node metastases
    • 5-year CSS
      • LN(-) —> 70-90%
      • LN(+) —> 30-40%
  • Older males
  • Tobacco and Alcohol
  • Oral cavity mucosa —> thick layer + keratin layer
    • Floor of mouth and ventral and lateral tongue —> thin mucosa w less keratin
      • Maybe that's why these subsites have more Ca incidence
  • Majority —> SCC
  • Minor salivary gland
  • Nonepithelial tumors
    • Melanoma
    • Lymphoma
    • Sarcoma
    • Ameloblastoma

Anatomy

Sub-divisions

Lip

  • Begin at the junction of the vermilion border with the skin
  • Ant border of oral vestibule
  • Vermillion surface
    • Pportion of the lip that comes in contact with the opposing lip
  • Motor nerve of lip :
    • Buccal and mandibular branches of the Facial nerve.

Oral Tongue

  • Anterior two thirds of the tongue
    • Mobile
  • From the circumvallate papillae to the undersurface of the tongue at the junction of the floor of mouth
  • The fibrous septum divides the tongue into right and left halves
  • Four anatomic areas:
    • Tip
    • Lateral borders
    • Dorsal surface
    • Ventral surface
  • Six pairs of muscles
    • 3 Extrinsic
      • Genioglossus
      • Hyoglossus
      • Styloglossus
      • These move the tongue
    • 3 Intrinsic
      • Lingual
      • Vertical
      • Transverse
      • These shape and comform the tongue during speech and swallowing
  • Lingual artery, tonsillar branch of the facial artery, and the ascending pharyngeal artery
  • Internal jugular vein
  • Sensation:
    • ant 2/3
      • Sensation —> Lingual nerve
        • A branch of the mandibular nerve (V3)
          • general somatic afferent
        • Also carries fibers from the facial nerve(taste from ant 2/3) —> this is Chorda tympani
        • Lingual n. also carries parasympathetic and sympathetic fibers.
          • A parasympathetic ganglion hangs from lingual n. within twi small fibers + one thin nerve from Chroda tympani
          • Submandibular Ganglion
      • Be aware of referred otalgia
        • Passing through foramen ovale —> a connection is made with Auriculotemporal n.
          • Now another question: What is auriculotemporal n.?
            • A branch of the mandibular nerve(V3)
            • Gives sensation to:
              • Parotid
              • Auricle
              • External acoustic meatus
              • Outer side of the tympanic membrane
              • Skin in the temporal region
              • Temporomandibular joint.
        • At Gasserian ganglion
      • Taste —> Chroda tympani n. as discussed ;)
    • post 1/3 and circumvallate papillae

Floor of the Mouth

  • Lingual n.
  • Semilunar space
  • From the lower alveolar ridge to the undersurface of the tongue
  • Overlies the mylohyoid and hyoglossus muscles
    • Mylohyoid m. supports anterior
    • Hyoglossus m. supports posterior
      • Lingual n. and Hypoglossal n, are lateral to this muscle
      • Lingual a. is medial to this muscle.
  • Posterior boundary —> base of the anterior tonsillar pillar
  • Divided into right and left by the frenulum
    • Contains the ostia of the submandibular and sublingual salivary glands

Hard Palate

  • Extends from the inner surface of the superior alveolar ridge to the posterior edge of the palatine bone

Alveolar Ridge

  • Alveolar processes of the maxilla and mandible and the overlying mucosa
  • From the line of attachment of mucosa in the buccal gutter to the line of free mucosa of the floor of mouth
  • Lower part —> ascending ramus of the mandible posteriorly
  • Superior alveolar ridge mucosa —> from the line of attachment of mucosa in the upper gingival buccal gutter to the junction of the hard palate
  • Posterior margin —> upper end of the pterygopalatine arch