Figure 1.

Illustration of the head and neck. The oral cavity includes the mucosal surface of the lips, the anterior two-thirds of the tongue, buccal mucosa, retromolar trigone and the hard palate. The oropharynx just posterior to the oral cavity includes the soft palate, the palatine tonsils, and base of the tongue. The nasopharynx located superiorly is bordered by the nasal cavity, clivus, soft palate, and sphenoid. The larynx includes the supraglottis, glottis, and subglottis. The hypopharynx just posterior to the larynx includes the following subsites: piriform sinus, postcricoid space, and posterior pharyngeal wall. Additional sites of the head and neck including the nasal cavity and paranasal sinuses (not imaged). Copyright 2005-2011 American Society of Clinical Oncology. Robert Morreale/Visual Explanations, LLC.