Overview of Esophageal and Swallowing Disorders By Kristle Lee Lynch, MD, Perelman School of Medicine at The University of Pennsylvania Reviewed / Revised Mar 2022 | Modified Sep 2022 View Patient Education The swallowing apparatus consists of the pharynx, upper esophageal (cricopharyngeal) sphincter, the body of the esophagus, and the lower esophageal sphincter (LES).