



THE LYMPHATICS OF THE THORAX 71' 



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 pleurae 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; (6) 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 anasto- 

 moses 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 

 iexus 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 (lymphoglandulce 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 pericar- 

 dium, and from the sternal glands; their efferents unite with those of the tracheo- 

 bronchial glands, to form the right and left bronchomediastinal trunks. 



The Posterior Mediastinal Glands (lymphoglandulce 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. 622) form four main groups: (a) tracheal, 

 on either side of the trachea; (6) bronchial, in the angles between the lower part 

 of the trachea and bronchi and in the angle between the two bronchi ; (c) broncho- 

 pulmonary, 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 broncho- 

 mediastinal 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. 





