ABSTRACT

The hypopharynx is a funnel-shaped structure that includes the sub-sites of the piriform fossa or sinus (laterally), the posterior pharyngeal wall (posteriorly) and the post-cricoid oesophagus (inferiorly). The piriform fossa extends from the pharyngoepiglottic fold to the upper end of the oesophagus. It is bound laterally by the thyroid cartilage and medially by the hypopharyngeal surface of the aryepiglottic fold and the arytenoids and cricoid cartilage. The posterior pharyngeal wall extends from the superior level of the hyoid bone (or floor of the vallecula) to the level of the inferior border of the cricoid cartilage and from the apex of one piriform sinus to the other.