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Other Terms: Gullet, Oesophagus, Oesophage, Speiseröhre, Esófago
The veins follow a similar path as the arteries.
The epithelial lining of the esophagus arises from mesoderm and the surrounding muscle and connective tissue layers arise from mesenchyme.
The arteries supplying the esophagus are derived from the inferior thyroid branch of the thryocervical trunk, from the descending thoracic aorta, from the left gastric branch of the celiac trunk, and from the left inferior phrenic of the abdominal aorta.
The nerves are derived from the vagi and from the sympathetic trunks. These nerves form a plexus between the two muscular layers. They also form a second plexus in the submucous tissue.
The esophagus has four layers: tunic mucosa, tela submucosa, tunica muscularis, and the tunica adventitia. The tunica mucosa is the thick innermost layer of the esophagus. It is composed of longitudinal folds. Its surface is studded with minute papillae and it is covered throughout with a thick layer of stratified squamous epithelium. The tunica mucosa is the protective lining of the esophagus. The tela submucosa connects the tunica mucosa and the tunica muscularis. It contains blood vessels, nerves, and mucous glands. It is composed of loose collagenous connective tissue. The tunica muscularis is composed of two planes of considerable thickness: an external of longitudinal fibers and an internal of circular fibers. The longitudinal fibers are arranged at the commencement of the tube in three fasciculi: one in front and one on either side. As these fibers descend they blend together to form a uniform layer. The circular fibers are continuous above with the inferior pharyngeal constrictor. Their direction is transfers at the upper and lower parts of the tube, but oblique in the middle portion. The upper muscular fibers are striated skeletal muscle that are used for voluntary swallowing. The lower half is smooth muscle to carry the food to the stomach. The tunica adventitia wraps around the esophagus. it is composed of dense irregular collagenous connective tissue.
The esophagus is a muscular tube, about 24 cm long, running from the pharynx to the stomach. It begins in the neck at the lower border of the cricoid cartilage, and descends along the front of the vertebral column. It then pierces through the diaphragm, through the esophageal hiatus, entering the abdomen and ends at the opening of the stomach. The esophagus in general runs vertically, however it doesmake two slight curves in its course. At its commencement it is placed in the midline, but it curves slightly to the left as far as the root of the neck. It then gradually travels back to the midline at the level of the fifth thoracic vertebrae, and finally it travels back to the left as it passes forward to the esophageal hiatus in the diaphragm. The esophagus also presents antero-posterior flexures corresponding to the curvatures of the vertebral column. It is the narrowest part of the digestive tube, and is most contracted at its commencement, and at the point where it passes through the diaphragm.
In the cervical region the trachea is anterior to the esophagus. At the lower part of the neck, where it is slightly to the left, the thyroid gland is also anterior to the esophagus. Posterior to the Esophagus is the vertebral column and longus colli muscles. Just lateral on either side of the trachea are the common carotid arteries. The recurrent nerves run between it and the trachea, and to its left is the thoracic lymphatic duct. As the esophagus enters the thorax it is sandwiched between the trachea anterior, and the vertebral column posterior. As it descends it passes posterior and to the right of the aortic arch, it continues down on the right side of the aorta. It then runs in front and a little to the left of the aorta and enter the abdomen through the diaphragm at the level of the tenth thoracic vertebra. Just before it perforates the diaphragm, it presents a distinct dilatation. Anteriorly, it is in relationship with the trachea, the left bronchus, the pericardium, and the diaphragm. Posteriorly, it rests upon the vertebral column, the longus colli muscles, the right aortic intercostal arteries, the thoracic duct and the hemiazygos veins. Near the diaphragm, it rests upon the aorta posteriorly. On its left side, are the terminal portions of the aortic arch, the left subclavian artery, the thoracic duct, and the left pleura. Further down, it is in relation on its lefts side with the descending thoracic aorta. On its right side are the right pleura and the azygos vein which it overlaps. The vagi nerves descend in close contact with the esophagus below the roots of the lungs. The right and left vagus nerves unite to form a plexus around the esophagus. The abdominal portion of the esophagus lies in the esophageal groove on the posterior surface of the left lobe of the liver. Only its anterior and left aspects are covered by peritoneum.