Esophagus

About the Esophagus

The esophagus is a muscular tube approximately 25 cm long connecting the pharynx to the stomach. It passes through the diaphragm at the esophageal hiatus at T10. The upper esophageal sphincter UES is the cricopharyngeus muscle, preventing air entry. The lower esophageal sphincter LES prevents acid reflux. The esophageal wall has mucosa stratified squamous epithelium, submucosa with esophageal glands, muscularis externa upper one third skeletal muscle for voluntary swallowing, middle one third mixed, lower one third smooth muscle, and adventitia no serosa, making esophageal cancer spread easily. Swallowing deglutition has three phases: oral voluntary, pharyngeal involuntary and rapid, esophageal peristalsis. Primary peristalsis follows the food bolus. Secondary peristalsis is triggered by distension if primary fails. Achalasia involves failure of LES relaxation and absent peristalsis, treated with pneumatic dilation, Heller myotomy, or POEM. GERD results from LES incompetence. Barrett esophagus is intestinal metaplasia from chronic reflux, a precursor to adenocarcinoma. Mallory Weiss tears from vomiting cause upper GI bleeding.