sophage

The esophagus, or oesophagus, is a muscular tube that transports swallowed material from the pharynx to the stomach. In adults it measures about 25 centimeters in length and lies behind the trachea, passing through the mediastinum and the diaphragmatic hiatus to reach the gastroesophageal junction.

Structure and innervation: The esophageal wall consists of mucosa, submucosa, and muscularis propria, with an outer adventitia rather than a serosa. The mucosa is lined by nonkeratinized stratified squamous epithelium in most of its course. The muscular layer comprises an inner circular and an outer longitudinal layer. The upper esophageal sphincter, formed by the cricopharyngeus muscle, maintains tone at the top, while the lower esophageal sphincter near the gastroesophageal junction helps prevent reflux. Blood supply comes from branches of the aorta in the thorax and from the left gastric and inferior phrenic arteries in the abdomen. Venous drainage mirrors these vessels, and lymphatics drain to regional cervical, mediastinal, and celiac nodes. Parasympathetic input largely travels via the vagus nerves, supporting coordinated peristalsis.

Function: The esophagus conducts a swallowed bolus to the stomach using coordinated peristaltic waves. Primary peristalsis follows swallowing; secondary peristalsis clears remnants. The LES and diaphragmatic contact help prevent reflux, while the esophagus also participates in protective reflexes against regurgitation.

Clinical relevance: Common disorders include gastroesophageal reflux disease with esophagitis; Barrett’s esophagus, a metaplastic change associated with increased cancer risk; esophageal cancer (squamous cell in the mid to upper esophagus, adenocarcinoma in the distal esophagus). Motility disorders such as achalasia cause dysphagia. Diagnosis relies on endoscopy, imaging, manometry, and pH monitoring; treatment ranges from lifestyle modification and acid suppression to dilation, stenting, and surgical or oncologic therapies.