Oral cavity

Last revised by Craig Hacking on 20 Feb 2024

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

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 cavity formed by oral vestibule and oral cavity proper:

  • The oral vestibule is the space between the labial and buccal mucosa anteriorly/laterally and posteriorly/medially the teeth and gingiva. Mylohyoid muscles are located at its floor 5 and the hard palate forms the roof.

  • Posteriorly, the oral cavity proper 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:

Lymphatic drainage of the oral cavity includes submental, submandibular, retropharyngeal, and deep cervical nodes 5.

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