The esophagus (oesophagus) is an organ in vertebrates which consists of a muscular tube through which food passes from thepharynx to the stomach. During swallowing, food passes from the mouth through the pharynx into the esophagus and travels viaperistalsis to the stomach. The word esophagus is derived from the Latin œsophagus, which derives from the Greek wordoisophagos, lit. “entrance for eating.” In humans the esophagus is continuous with the laryngeal part of the pharynx at the level of the C6 vertebra. The esophagus passes through posterior mediastinum in thorax and enters abdomen through a hole in the diaphragm at the level of the tenth thoracic vertebrae (T10). It is usually about 10–50 cm long depending on individual height. It is divided into cervical, thoracic and abdominal parts. Due to the inferior pharyngeal constrictor muscle, the entry to the esophagus opens only when swallowing or vomiting.