The human trachea and esophagus are not one tube. The trachea and esophagus are both located in the middle of the neck, with the trachea in front and the esophagus behind. The trachea and esophagus belong to two different systems. The trachea belongs to the body’s respiratory system and the esophagus belongs to the body’s digestive system. The trachea is connected to the pharynx through the voice box and to the bronchial tubes below, and is the passageway for gases to come in and go out when breathing; while the esophagus is connected to the larynx and to the cardia, and is the passageway for food to pass through when the human body eats. So both cannot be the same tube. Usually, inflammation of the trachea will have obvious symptoms of coughing and phlegm. Inflammation of the esophagus may have symptoms such as nausea, acid reflux and vomiting. Clinically, some lesions in the trachea and lungs can be detected by chest CT and other tests. Some lesions in the esophagus can be detected through endoscopy, barium meal and other tests.