Oral cavity

Last revised by Dr Daniel J Bell on 20 Jan 2022

The oral cavity, also known as the mouth, 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.

The oral vestibule is the space between the labial and buccal mucosa anteriorly/laterally and posteriorly/medially the teeth and gingiva.

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 (fauces) is the relatively constricted opening between the oral cavity and the oropharynx, but is considered to be part of the oropharynx.


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

Related pathology

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Cases and figures

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