The pharyngoesophageal sphincter (PES) is a high pressure zone between the pharynx and the esophagus. The cricopharyngeal muscle (CPM) is a main component of the PES. The clinical importance of the PES is well known, but details of its anatomy and histology have not been well described. Recent studies examining the histology of the CPM indicate that many features of a normal CPM are considered pathologic in other skeletal muscles. This fact raises questions regarding the findings in diseased CPMs.