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FIG. 90621 Deep lymph nodes and vessels of the thorax and abdomen (diagrammatic). Afferent vessels are represented by continuous lines, and efferent and internodular vessels by dotted lines. (Cunningham.) |
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The deep lymphatic vessels of the thoracic wall (Fig. 90621) consist of: |
1. The lymphatics of the muscles which lie on the ribs: most of these end in the axillary glands, but some from the Pectoralis major pass to the sternal glands. 2. The intercostal vessels which drain the Intercostales and parietal pleura. Those draining the Intercostales externi run backward and, after receiving the vessels which accompany the posterior branches of the intercostal arteries, end in the intercostal glands. Those of the Intercostales interni and parietal pleura consist of a single trunk in each space. These trunks run forward in the subpleural tissue and the upper six open separately into the sternal glands or into the vessels which unite them; those of the lower spaces unite to form a single trunk which terminates in the lowest of the sternal glands. 3. The lymphatic vessels of the diaphragm, which form two plexuses, one on its thoracic and another on its abdominal surface. These plexuses anastomose freely with each other, and are best marked on the parts covered respectively by the pleuræ and peritoneum. That on the thoracic surface communicates with the lymphatics of the costal and mediastinal parts of the pleura, and its efferents consist of three groups: (a) anterior, passing to the gland which lie near the junction of the seventh rib with its cartilage; (b) middle, to the glands on the esophagus and to those around the termination of the inferior vena cava; and (c) posterior, to the glands which surround the aorta at the point where this vessel leaves the thoracic cavity. |
The plexus on the abdominal surface is composed of fine vessels, and anastomoses with the lymphatics of the liver and, at the periphery of the diaphragm, with those of the subperitoneal tissue. The efferents from the right half of this plexus terminate partly in a group of glands on the trunk of the corresponding inferior phrenic artery, while others end in the right lateral aortic glands. Those from the left half of the plexus pass to the pre- and lateral aortic glands and to the glands on the terminal portion of the esophagus. |
The visceral lymph glands consist of three groups, viz.: anterior mediastinal, posterior mediastinal, and tracheobronchial. |
The Anterior Mediastinal Glands (lymphoglandulæ mediastinales anteriores) are placed in the anterior part of the superior mediastinal cavity, in front of the aortic arch and in relation to the innominate veins and the large arterial trunks which arise from the aortic arch. They receive afferents from the thymus and pericardium, and from the sternal glands; their efferents unite with those of the tracheobronchial glands, to form the right and left bronchomediastinal trunks. |
The Posterior Mediastinal Glands (lymphoglandulæ mediastinales posteriores) lie behind the pericardium in relation to the esophagus and descending thoracic aorta. Their afferents are derived from the esophagus, the posterior part of the pericardium, the diaphragm, and the convex surface of the liver. Their efferents mostly end in the thoracic duct, but some join the tracheobronchial glands. |
The Tracheobronchial Glands (Fig. 90622) form four main groups: (a) tracheal, on either side of the trachea; (b) bronchial, in the angles between the lower part of the trachea and bronchi and in the angle between the two bronchi; (c) bronchopulmonary, in the hilus of each lung; and (d) pulmonary, in the lung substance, on the larger branches of the bronchi. The afferents of the tracheobronchial glands drain the lungs and bronchi, the thoracic part of the trachea and the heart; some of the efferents of the posterior mediastinal glands also end in this group. Their efferent vessels ascend upon the trachea and unite with efferents of the internal mammary and anterior mediastinal glands to form the right and left bronchomediastinal trunks. The right bronchomediastinal trunk may join the right lymphatic duct, and the left the thoracic duct, but more frequently they open independently of these ducts into the junction of the internal jugular and subclavian veins of their own side. |
In all town dwellers there are continually being swept into these glands from the bronchi and alveoli large quantities of the dust and black carbonaceous pigment that are so freely inhaled in cities. At first the glands are moderately enlarged, firm, inky black, and gritty on section; later they enlarge still further, often becoming fibrous from the irritation set up by the minute foreign bodies with which they are crammed, and may break down into a soft slimy mass or may calcify. |
The lymphatic vessels of the thoracic viscera comprise those of the heart and pericardium, lungs and pleura, thymus, and esophagus. |
The Lymphatic Vessels of the Heart consist of two plexuses: (a) deep, immediately under the endocardium; and (b) superficial, subjacent to the visceral pericardium. The deep plexus opens into the superficial, the efferents of which form right and left collecting trunks. The left trunks, two or three in number, ascend in the anterior longitudinal sulcus, receiving, in their course, vessels from both ventricles. On reaching the coronary sulcus they are joined by a large trunk from the diaphragmatic surface of the heart, and then unite to form a single vessel which ascends between the pulmonary artery and the left atrium and ends in one of the tracheobronchial glands. The right trunk receives its afferents from the right atrium and from the right border and diaphragmatic surface of the right ventricle. It ascends in the posterior longitudinal sulcus and then runs forward in the coronary sulcus, and passes up behind the pulmonary artery, to end in one of the tracheobronchial glands. |
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FIG. 90622 The tracheobronchial lymph glands. (From a figure designed by M. Hallé.) |
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The Lymphatic Vessels of the Lungs originate in two plexuses, a superficial and a deep. The superficial plexus is placed beneath the pulmonary pleura. The deep accompanies the branches of the pulmonary vessels and the ramifications of the bronchi. In the case of the larger bronchi the deep plexus consists of two net-worksone, submucous, beneath the mucous membrane, and another, peribronchial, outside the walls of the bronchi. In the smaller bronchi there is but a single plexus, which extends as far as the bronchioles, but fails to reach the alveoli, in the walls of which there are no traces of lymphatic vessels. The superficial efferents turn around the borders of the lungs and the margins of their fissures, and converge to end in some glands situated at the hilus; the deep efferents are conducted to the hilus along the pulmonary vessels and bronchi, and end in the tracheobronchial glands. Little or no anastomosis occurs between the superficial and deep lymphatics of the lungs, except in the region of the hilus. |
The Lymphatic Vessels of the Pleura consist of two setsone in the visceral and another in the parietal part of the membrane. Those of the visceral pleura drain into the superficial efferents of the lung, while the lymphatics of the parietal pleura have three modes of ending, viz.: (a) those of the costal portion join the lymphatics of the Intercostales interni and so reach the sternal glands; (b) those of the diaphragmatic part are drained by the efferents of the diaphragm; while (c) those of the mediastinal portion terminate in the posterior mediastinal glands. |
The Lymphatic Vessels of the Thymus end in the anterior mediastinal, tracheobronchial, and sternal glands. |
The Lymphatic Vessels of the Esophagus form a plexus around that tube, and the collecting vessels from the plexus drain into the posterior mediastinal glands. |