Thoracic vessels

First level of thoracic vessels Aorta, pulmonary trunk, ductus arteriosus, atria, bronchus, pulmonary vein and arteries, and vena cava (see Note 11). 

Second level of thoracic vessels—aortic arch arteries, common carotid and subclavian arteries, and innominate/brachiocephalic artery. 

It was emphasized that any thoracic penetration may result in acute life-threatening injuries such as tension pneumothorax, hemothorax, massive cardiac injury with tamponade, great vessel injury, hemoptysis, and lung coUapse. Thermoset mbber bullets can also cause serious injuries, as shown in Figure 7.2. 

Microorganisms that escape phagocytosis in a local lesion may now be transported to the regional lymph nodes via the lymphatic vessels. If massive invasion occurs with which the resident macrophages are unable to cope, microorganisms may be transported through the thoracic duct into the bloodstream. The appearance of viable microorganisms in the bloodstream is termed bacteraemia and is indicative of an invasive infection and failure of the primary defences. 

Chylomicrons leave the absorptive cell by way of exocytosis. Because they are unable to cross the basement membrane of the blood capillaries, the chylomicrons enter the lacteals, which are part of the lymphatic system. The vessels of the lymphatic system converge to form the thoracic duct that drains into the venous system near the heart. Therefore, unlike products of carbohydrate and protein digestion that are transported directly to the liver by way of the hepatic portal vein, absorbed lipids are diluted in the blood... 

Chylomicrons are discharged from the enterocytes by exocytosis into lacteals, which are lymphatic vessels that originate in the intestinal villi, drain into the cisternae chyli, and follow a course through the thoracic ducts to enter the bloodstream through the left subclavian vein. 

Fig. 17.3. Selective spinal DSA in a 59-year-old woman, p.a. projection. Injection of the 12th left thoracic segmental artery. Filling of the radiculomedullary arteries T12 and T10 on the left side (arrows) and the anterior spinal artery system. Collateral filling of the right-sided segmental arteries via retrocorpo-ral anastomoses (arrowheads). These extradural anastomoses can compensate for focal vessel occlusions at the level of the radicular artery...

AVMs of the perimedullary fistula type are direct AV shunts that are located on the ventral or dorsal surface of the spinal cord or the conus medullaris, usually in the thoracolumbar area, occasionally thoracic, and rarely cervical. Their location thus is intradural, intra- or extramedullary. They are always supplied by spinal cord vessels, either by the anterior spinal artery (ventrally) or by a posterolateral artery (dorsally), depending on their location. They drain into spinal cord veins (Fig. 17.12). Drainage may even ascend up to the foramen magnum or into the posterior fossa. 

The LCX is punctuated distal to the flow probe with a chrome-vanadium-steel electrode (3 mm length, 1 mm diameter). The electrode (anode) is placed in the vessel in contact with the intimal lining and connected over a Teflon coated wire to a 9 Volt battery, a potentiometer and an amperemeter. A disc electrode (cathode) is secured to a subcutaneous thoracal muscle layer to complete the electrical circuit. The intima is stimulated with 150 pA for 6 h. During this time, gradually an occluding thrombosis is formed. 

The newly synthesized triacylglycerol becomes organized into chylomicrons (a type of lipoprotein see next section), which are secreted by the intestinal epithelial cell into the lacteals, small lymph vessels in the villi of the small intestine. Then from the lymphatics, the chylomicrons pass into the thoracic duct, from which they enter the blood and thus contribute to the transport of lipid fuel to various tissues. A feature of chylomicron metabolism is their ability to deliver lipid fuels to extrahepatic tissues. 

Lymphatic vessels infiltrate tissues that are bathed in fluid released from blood into those tissues. Pockets of fluid collect in the tissues, and increased pressure allows the fluid to seep into the lymphatic vessels. Whereas blood vessels return deoxygenated blood to the heart to be pumped to the lungg for oxygen, lymphatic vessels return fluid that has leaked out of the capillaries into various tissues. However, before this lymphatic fluid is rejoined with venous fluid at the thoracic duct, it is filtered through the lymph nodes to remove infectious agents. 

The total blood flow from the vessels of the splanchnic bed through the portal vein as well as the chyle and lymph flow through the thoracic duct must pass the liver. The same applies to the systemic blood flow. Therefore, the liver is indeed the central organ for checking the blood for foreign particles and substances as well as for endogenous substances which must be eliminated for physiological reasons. For these vital functions, the RES cells are provided with special capabilities (2, 48, 64, 69, 73, 85, 86, 88, 91) ... 

In cases of obstructive jaundice, bilirubin enters the lymphatic vessels, so that the lymphatic fluid is already icteric when it enters the thoracic duct. Exudates and transudates are always yellow-coloured in a certain correlation to the serum bilirubin values, although they contain less bilirubin (in accordance with their lower protein content) than the serum itself. Due to their larger protein content, exudates are more icteric in colour than transudates. Icteric colouring is hardly or not at all evident on paralyzed parts of the body. It would appear that bilirubin concentration also depends on normal nerve function. As a rule, jaundice is not detected in the region of an oedema (J. Meakins, 1927 J.H. Page, 1929). 

If acupuncture, which entails tissue trauma, is performed properly and on the correct acupuncture points, trauma will affect only the skin and the connective tissue below. If, however, acupuncture needles are inserted at the wrong site or penetrate too deeply, other tissues or organs can be affected. Traumatic complications of acupuncture have been reviewed (108). They have been described in relation to the thoracic and abdominal viscera, in the peripheral and central nervous systems, and in blood vessels. Several deaths have been reported from pneumothorax and cardiac tamponade. The anatomical tissues at several acupuncture points are such that needles can injure vulnerable structures. Thus, good knowledge of anatomy is an essential precondition for acupuncturists. 

FIGURE 2.37 Thoracic duct and other vessels of the thorax. Lymphatic capillaries are most numerous just beneath body surfaces, such as the skin and the mucus membranes of the gastrointestinal and respiratory tracts. The mucus membrane of the gastrointestinal tract is called the gut mucosa. The general function of these capillaries is to absorb interstitial fluid that has leaked from the circulatory system and to return it to the bloodstream. The function of the l)miphatic capillaries that end in the lacteals of the small intestine is to transport absorbed dietary lipids. These capillaries coalesce and eventually deliver their contents to the thoracic duct. The lymph collected from other parts of the body, as indicated by the "collecting trunk," also is transferred to the thoracic duct. [Redrawn with permission, from "Grant s Atlas of Anatomy," Williams Wilkins Co., Baltimore, 1978.]... 

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