What Is the Posterior Mediastinum?

The posterior mediastinum is located between the pericardium and the spine and chest. There are esophagus, thoracic aorta, odd vein, hemi-singular vein, parasemi-venous vein, thoracic duct, vagus nerve, sympathetic dry chest and large and small internal organs. Among them, the esophagus, thoracic duct, vagus nerve and sympathetic trunk pass through the superior mediastinum and posterior mediastinum.

Posterior mediastinum

The posterior mediastinum is located between the pericardium and the spine and chest. There are esophagus, thoracic aorta, odd vein, hemi-singular vein, parasemi-venous vein, thoracic duct, vagus nerve, sympathetic dry chest and large and small internal organs. Among them, the esophagus, thoracic duct, vagus nerve and sympathetic trunk pass through the superior mediastinum and posterior mediastinum.

Chinese name

Posterior mediastinum

Foreign name

After the mediastinum

Location

Screed the upper sternal angle

Department

The esophagus is at the forefront of the posterior mediastinum

in

The esophagus and chest account for about 7/10 of the total length of the esophagus and are about 18cm in length. The upper part of the esophagus is connected to the esophagus and neck through the upper mouth.

Segmentation

Divided into the neck, chest, and abdomen according to the location of the esophagus. The esophagus and chest are divided into the upper chest and the chest with the lower edge of the trachea branch as the boundary. The commonly used segmentation method in clinical is to mark the upper edge of the aortic arch and the lower edge of the inferior pulmonary vein, and divide the esophagus into upper, middle and lower segments. The upper segment is from the beginning of the esophagus to the upper edge of the aortic arch, the middle segment of the autonomic arch is from the upper edge to the inferior pulmonary vein, and the lower segment is from the lower edge of the lower pulmonary vein to the end of the esophagus.

stroke

From the upper thorax to the upper mediastinum, it is located slightly to the left between the trachea and the spine, and passes downwards through the trachea branch, and gradually lies on the midline. It descends from the right side of the thoracic aorta along the pericardium to the seventh thoracic spine. On the left, descending from the front of the thoracic aorta to the left and front to the 10th thoracic vertebra. As can be seen from the above, the esophagus is curved. Viewed from the side, the esophagus is concavely curved forward, and its curvature is consistent with the spine chest curve; viewed from the front, the upper section is left, the middle section is right, and the lower section is left, showing two mild lateral curves.

Adjoin

Anterior to the esophagus are the trachea, tracheal branch, left recurrent laryngeal nerve, left main bronchus, right pulmonary artery, pericardium, left atrium, and diaphragm. The left main bronchus spans the anterior esophagus to the left in the fourth and fifth thoracic vertebrae, where the esophagus is narrow and is often incarcerated by foreign bodies. Below the 5th thoracic spine, the esophagus is adjacent to the left atrium, and enlargement of the left atrium can compress the esophagus. There is the spinal thoracic segment and the posterior esophageal space between it and the esophagus. There are singular veins, semi-singular veins, parasemi-singular veins, thoracic ducts, thoracic aorta, and right posterior intercostal artery in the gap. The left common carotid artery, left subclavian artery, end of aortic arch, thoracic aorta, superior thoracic duct, and left mediastinal pleura are on the left. There is an odd vein arch on the right and a mediastinal pleura. In addition, on both sides of the esophagus, the vagus nerve descends around the root of the lungs, the left side goes down to the front of the esophagus, and the right side goes behind the esophagus, forming the anterior and posterior plexus of the esophagus, and the esophageal branch from the plexus to the esophagus, and the remaining fibers continue to The inferior vagus nerve is anterior and posterior, and passes through the esophageal hiatus to the abdominal cavity.

The relationship between esophagus and pleura

The part of the left side of the esophagus that is above the aortic arch is attached to the left mediastinal pleura. There is a thoracic duct and aortic arch. It is below the aortic arch and above the 7th thoracic vertebra. The esophagus is not attached to the mediastinal pleura. . The place where the esophagus and the mediastinal pleura meet, that is, where the upper and lower esophagus triangles are located. The right part of the esophagus is attached to the mediastinal pleura except the arch of the odd vein. The right mediastinal pleura often protrudes below the root of the lungs to the back of the esophagus and reaches the midline, forming a self-operating crypt. In the next stage of surgery, there is a possibility of rupturing the pleural cavity.

Stenosis and esophageal sphincter

There are three physiological narrows of the esophagus, two of which are located in the chest, where they intersect with the left main bronchus and at the transesophageal hiatus. The narrow range is about 1.5-1.7cm.

Blood vessels, lymph and nerves

The arteries of the upper thoracic segment of the esophagus come from the upper posterior intercostal artery and the bronchial branch, with 5 branches more common. The arteries of the lower thoracic segment come from the esophageal arteries and are more common in 1-2 branches. The esophagus wall is rich in veins, forming a plexus in the submucosa and around the esophagus, called the esophageal venous plexus. The plexus converges into several esophageal veins, and is injected into the odd vein, semi-odd vein, or parahemischid vein. The esophageal venous plexus has a rich anastomosis with the left gastric venous branch. When portal hypertension occurs, collateral circulation between the portal veins can be established through this route. Therefore, the blood flow of the esophageal venous plexus increases, which can cause esophageal varices. Even rupture and bleeding. The upper esophageal and thoracic lymphatic tubes were injected into the tracheobronchial and paratracheal lymph nodes, and the lower thoracic lymphatic tubes were injected into the mediastinal and left gastric lymph nodes. There are still some lymph vessels in the esophagus and chest, which are directly injected into the thoracic duct without local lymph nodes. The nerves of the esophagus come from the thoracic sympathetic trunk and the vagus nerve. The esophageal striated muscle is innervated by the recurrent laryngeal nerve, the smooth muscles and glands are innervated by the sympathetic and parasympathetic nerves, and the sensory impulses of the mucosa are accompanied by the sympathetic and vagus nerves into the spinal cord or brain.