Development, anatomy, and physiology of the esophagus

Abstract

Esophageal embryonic development and anatomic features play an important role in both normal function and common pathology of the esophagus. The embryonic endoderm provides the scaffolding for the future esophagus, which will ultimately connect the pharynx to the stomach. The developed esophagus has close anatomic relationships with the cervical spine, thoracic aorta, left atrium, and diagphragmatic haitus-relationships associated with esophageal pathology. Esophageal musculature is composed of an external layer of longitudinal fibers and an internal layer of circular fibers which provide peristaltic force; the backflow of food and acidic gastric contents is prevented at the level of two high-pressure regions: the upper and the lower esophageal sphincters. Microscopically, the esophageal wall is composed of four layers: internal mucosa, submucosa, muscularis propria, and adventitia. The esophagus has a segmental arterial supply without dedicated vasculature. Venous drainage is notable for being a portal-caval connection susceptible to portal hypertension. Esophageal innervation occurs via the sympathetic and parasympathetic nervous systems, as well as the intrinsic enteric nervous system.