Zenker's diverticulum

Last reviewed 01/2018

A pharyngeal pouch is a pulsion diverticulum of the pharyngeal mucosa through Killian's dehiscence, an area of weakness between the two parts of the inferior pharyngeal constrictor - the thyropharyngeus and the cricopharyngeus - at their posterior margin.

The pouch probably arises as a result of a relative obstruction at the level of the cricopharyngeus. At first, it develops posteriorly but then it protrudes to one side, usually the left. As it enlarges, it displaces the oesophagus laterally.