Oral cavity

The oral cavity is the most proximal portion of the aerodigestive tract, and is continuous posteriorly with the oropharynx.  

Gross anatomy


The oral cavity includes the lips anteriorly. For purposes of staging oral carcinoma according to the 8th edition of the AJCC TNM staging system, the oral cavity starts at the portion of the lip that contacts the opposed lip (wet mucosa) and excludes the dry vermilion lip.

Posteriorly, the oral cavity extends to a ring of structures (circumvallate papillae, anterior tonsillar pillars, and junction of hard and soft palates) that divides it from the oropharynx.

The oropharyngeal isthmus is the relatively constricted opening between the oral cavity and the oropharynx. The narrowing is caused by the fauces of the palatine tonsils; the isthmus is important for phonation 5.


The oral cavity is divided into a number of subsites both anatomically and for the purposes of cancer staging:

Related pathology

Anatomy: Head and neck

Anatomy: Head and neck

Article information

rID: 9616
System: Head & Neck
Section: Anatomy
Synonyms or Alternate Spellings:
  • Oral cavities
  • Isthmus (oral cavity)
  • Oral cavity subsites
  • Subsites of the oral cavity

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Cases and figures

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