HYPOPHARYNGEAL DIVERTICULUM (PHARYNGEAL POUCH) INTRODUCTION
The area of weakness is of absolutely no consequence unless there is a slight disorder of the swallowing mechanism, in which the cricopharyngeus muscle below the gap fails to relax in front of a bolus of food which is being swallowed. Swallowing is initiated by the tongue and continued by the pharyngeal muscles. As a food bolus approaches the cricopharyngeus muscle, which forms the upper sphincter of the gullet, the muscle normally relaxes in front of it to allow it to pass and then closes again behind it to prevent regurgitation. After this, a wave of muscular activity carries the food bolus down the length of the oesophagus.