Human Anatomy and Physiology - N. I. Fedyukovich 2003

Internal Organs
Digestive System
Esophagus

The Esophagus (esophagus) is a cylindrical tube 25—30 cm long that connects the Pharynx to The Stomach. It begins at the level of the VI cervical vertebra, passes through the thoracic cavity and the Diaphragm, and opens into the stomach to the left of the X—XI thoracic vertebra. The esophagus is divided into three parts: cervical, thoracic, and abdominal.

The cervical part is located between the Trachea and THE Vertebral Column, extending from the level of the VI cervical to the II thoracic vertebra. The recurrent laryngeal nerve and the common carotid artery run along both sides of the cervical esophagus.

The thoracic part of the esophagus is located initially in the superior and then in the posterior Mediastinum. At this level, the esophagus is surrounded by the trachea, Pericardium, Thoracic Aorta, left main bronchus, and the right and left vagus nerves.

The abdominal part of the esophagus, 1—3 cm long, connects to the cardiac part of the stomach. It has anatomical constrictions in three locations: the first at the level of the VI—VII cervical vertebrae; the second at the IV—V thoracic vertebrae; and the third where the esophagus passes through the diaphragm. Additionally, There are two physiological constrictions: the aortic constriction, where the esophagus crosses the aorta, and the caudal constriction, at the transition into the stomach.

The esophageal wall consists of the mucosa, submucosa, muscularis, and adventitia. The mucosa is lined with stratified squamous epithelium. The well-developed submucosa allows the mucosa to form longitudinal folds. Glands located within the mucosa and submucosa open into the esophageal lumen via their ducts. The muscularis is formed by an outer longitudinal and an inner circular layer. The adventitia covers only the cervical and thoracic PARTS OF THE esophagus, whereas the abdominal part is covered by the visceral Peritoneum. The adventitia allows the esophagus to alter its transverse diameter during the passage of a food bolus.