BackgroundZenker's diverticulum is a pharyngoesophageal outpouching of mucosa and submucosa through Killian's dehiscence.ObjectiveTo investigate the propensity for Zenker's diverticulum to occur on the left side by examining muscle thickness in Killian's dehiscence, and to explore correlations between muscle thickness, sex, height and age.MethodsThe study included 109 Caucasian cadavers, 52 male and 57 female. The mean thickest and thinnest measurements of left medial, left lateral, right medial and right lateral aspects of Killian's dehiscence were calculated. The paired student's t-test was used to determine significance.ResultsThe average left muscle layer was significantly thinner than the right muscle layer, in both medial and lateral aspects. Furthermore, medial muscle thickness was significantly thinner than its respective lateral aspect for both the left and right sides. No correlations were found between muscle thickness and cadavers’ sex, length or stature, or age.ConclusionThere was a significant difference in muscle thickness between the left and right sides of Killian's dehiscence. The findings suggest there is a reason why Zenker's diverticulum occurs predominantly on the left side. The study also showed a significant difference in muscle thickness between the medial and lateral aspects of Killian's triangle.

Zenker's diverticulum is a pulsion outpouching from the posterior pharyngeal wall. The anatomy of the wall has been proposed to be dehiscent in the region of the Killian's triangle, between the thyropharyngeus muscle (inferior pharyngeal constrictor) and the cricopharyngeus muscle. A dehiscence is a bursting open, splitting or gaping along natural or sutured lines. To the best of our knowledge, there have not been any studies to histologically analyze the posterior pharyngeal wall and the exact location of the dehiscence. We thus aim to determine the presence and characteristics of this area of possible dehiscence.