esophageal

Esophageal refers to the esophagus, a muscular tube that transports ingested material from the pharynx to the stomach. In adults it is about 25 cm long and extends from the cricoid cartilage in the neck to the stomach in the upper abdomen. The esophagus conducts food via coordinated peristaltic contractions and is aided by the upper and lower esophageal sphincters that regulate flow and prevent backflow.

Anatomy and histology: The esophageal wall consists of mucosa (usually non-keratinized stratified squamous epithelium), submucosa, and the muscularis propria (an inner circular and outer longitudinal layer). The outermost layer is adventitia, not a serosa. The upper esophageal sphincter (cricopharyngeus) and the lower esophageal sphincter (at the diaphragmatic hiatus) help control entry and passage of material. Blood supply comes from branches of the inferior thyroid and thoracic aorta; venous drainage includes the azygos and hemiazygos systems and the left gastric vein. Lymphatics drain to mediastinal and celiac nodes. Innervation is chiefly by the vagus nerves and the enteric nervous system.

Physiology: Swallowing has oral, pharyngeal, and esophageal phases. Peristaltic waves move boluses toward the stomach, while LES tone and transient relaxations regulate reflux. Esophageal clearance and mucosal protection maintain comfort and function.

Clinical aspects: Common conditions include gastroesophageal reflux disease (GERD), esophagitis, and Barrett’s esophagus, which can increase the risk of esophageal adenocarcinoma. Motility disorders such as achalasia impair LES relaxation. Diagnostic tools include endoscopy with biopsy, barium swallow studies, esophageal manometry, and pH monitoring. Treatments range from acid suppression and lifestyle changes to endoscopic or surgical interventions, such as fundoplication or esophagectomy for cancer.