Structural Analysis of the Thoracic Catheter

The thoracic catheter is the longest lymphatic duct in the body. It collects lymph from the left body, abdomen, and both lower extremities. The thoracic catheter generally forms an initial part in front of the 1st to 2nd lumbar vertebrae, which is called "cisternal chyle" here. Pass up the diaphragmatic aortic hiatus into the thoracic cavity and inject into the left venous angle. In the event of blockage or rupture, it can lead to chylothorax and chylothorax.

1. Anatomy of the thoracic catheter

(1) thoracic catheter

The thoracic catheter is the largest lymphatic vessel in the body, also known as the left lymphatic duct. The total length is about 30 to 40 cm. Generally, it is formed by the confluence of the left and right lumbar trunks and the intestinal trunk in front of the 1st to 2nd lumbar vertebrae. The beginning is a cystic enlargement called the cisterna chyli. After the beginning of the thoracic catheter, it is close to the front of the spine, ascends along the right rear of the abdominal aorta, passes through the aortic hiatus of the diaphragm, enters the posterior mediastinum of the thoracic cavity, and continues to ascend along the right front of the spine to the height of the fifth thoracic vertebra, through the aortic arch and esophagus It goes obliquely from the back to the left front of the spine, then rises along the left side of the esophagus, exits the upper thoracic mouth to the root of the neck, and arches to the left front and lower into the left venous angle. There are a pair of valves at the entrance to prevent lymphatic reflux. . Before being injected into the venous angle, the thoracic catheter received the left cervical, subclavian, and left bronchomediastinum. There are generally no valves at the entrances of these three trunks, which is one of the important factors for cancer cells to metastasize to the lymph nodes at the root of the neck through the thoracic catheter when there is a tumor in the thoracic and abdominal organs. The thoracic catheter collects lymph from the left upper body and the entire lower body, that is, the lymph in 3/4 of the human body flows into the veins through the thoracic catheter.

(2) Lymphatic ducts

Lymphatic ducts are the terminal part of the lymphatic system. The right cervical trunk, the right subclavian trunk, and the right bronchial-mediastinal trunk merge into the right lymphatic duct; the left cervical trunk, the left subclavian trunk, the left bronchial-mediastinal trunk, the intestinal trunk, and the left and right lumbar trunks merge into the thoracic catheter (the left lymphatic duct). The right lymphatic duct into the right venous angle and the thoracic catheter into the left venous angle. The wall structure of lymphatic ducts is similar to that of veins, but the three-layer structure is not as clear as the layering of the walls of large veins.

2. Morphological structure of the thoracic catheter and its surrounding structures

The thoracic catheter, also known as the "left lymphatic duct", is the longest and thickest lymphatic duct in the body. The catheter is 30 to 40 cm long and collects lymph from the lower limbs, pelvis, abdominal wall and its internal organs, left lung, left half heart, left half chest wall, left upper limb, and left half head. The lower end of the thoracic catheter originates from the fusiform enlarged cisterna chyle, ascends through the aortic hiatus into the thoracic cavity, and connects with the medial crus of the diaphragm at the hiatus. Therefore, the contraction of the diaphragmatic angle during breathing can promote the flow of lymph. The thoracic catheter is located in the thoracic cavity behind the posterior mediastinal esophagus, between the thoracic aorta and the azygos vein, ascends along the front of the spine, moves to the left at the 4th and 5th thoracic vertebrae. It crosses the back of the aortic arch and bends upward at the 7th cervical vertebra into a convex arch, and then enters the left internal jugular vein or the left venous angle, and three lymphatic trunks at the end are injected.