OF THE THORAX. 571 



terior mediastinum, forming a continuous chain by the side of the aorta and 

 oasophagus ; they communicate on each side with the intercostal, below with 

 the lumbar glands, and above with the deep cervical. 



The Superficial Lymphatics of the Front of the Thorax run across the great 

 Pectoral muscle, and those on the back part of this cavity lie upon the Trapezius 

 and Latissimus Dorsi ; they all converge to the axillary glands. The lymphatics 

 from the mamma run along the lower border of the Pectoralis Major, through a 

 chain of small lymphatic glands, and communicate with the axillary glands. 



The Deep Lymphatics of the Thorax are the intercostal, internal mammary, 

 and diaphragmatic. 



The intercostal lymphatics follow the course of the intercostal vessels, receiving 

 lymphatics from the intercostal muscles and pleura; they pass backwards to 

 the spine, and unite with lymphatics from the back part of the thorax and 

 spinal canal. After traversing the intercostal glands, they incline down the 

 spine, and terminate in the thoracic duct. 



The internal mammary lymphatics follow the course of the internal mammary 

 vessels; they commence in the muscles of the abdomen above the umbilicus, 

 communicating with the epigastric lymphatics, ascend between the fibres of the 

 Diaphragm at its attachment to the ensiforrn appendix, and in their course behind 

 the costal cartilages are joined by the intercostal lymphatics, terminating on 

 the right side in the right lymphatic duct, on the left side in the thoracic duct. 



The lymphatics of the Diaphragm follow the course of their corresponding 

 vessels, and terminate, some in front, in the anterior mediastinal and internal 

 mammary glands, some behind in the intercostal and hepatic lymphatics. 



The bronchial glands are situated round the bifurcation of the trachea and 

 roots of the lungs. They are ten or twelve in number, the largest being placed 

 opposite the bifurcation of the trachea, the smallest round the bronchi and their 

 primary divisions for some little distance within the substance of the lungs. 

 In infancy, they present the same appearance as lymphatic glands in other situa- 

 tions, in the adult they assume a brownish tinge, and in old age a deep black 

 color. Occasionally they become sufficiently enlarged to compress and narrow 

 the canal of the bronchi ; and they are often the seat of tubercle or deposits of 

 phosphate of lime. 



The lymphatics of the lung consist of two sets, superficial and deep: the former 

 are placed beneath the pleura, forming a minute plexus, which covers the outer 

 surface of the lung ; the latter accompany the bloodvessels, and run along the 

 bronchi : they both terminate at the root of the lungs in the bronchial glands. 

 The efferent vessels from these glands, two or three in number, ascend upon 

 the trachea to the root of the neck, traverse the tracheal and oesophageal glands, 

 and terminate on the left side in the thoracic duct, and on the right side in the 

 right lymphatic duct. 



The cardiac lymphatics consist of two sets, superficial and deep ; the former arise 

 in the subserous areolar tissue of the surface, and the latter beneath the inter- 

 nal lining membrane of the heart. They follow the course of the coronary ves- 

 sels ; those of the right side unite into a trunk at the root of the aorta, which, 

 ascending across the arch of that vessel, passes backwards to the trachea, upon 

 which it ascends, to terminate at the root of the neck in the right lymphatic 

 duct. Those of the left side unite into a single vessel at the base of the heart, 

 which, passing along the pulmonary artery, and traversing some glands at the 

 root of the aorta, ascends on the trachea to terminate in the thoracic duct. 



The thymic lymphatics arise from the spinal surface of the thymus gland, and 

 terminate on each side in the internal jugular veins. 



The thyroid lymphatics arise from either lateral lobe of this organ; they con- 

 verge to form a short trunk, which terminates on the right side in the right 

 lymphatic duct, on the left side in the thoracic duct. 



The lymphatics of the oesophagus form a plexus round that tube, traverse the 

 glands in the posterior mediastinum, and, after communicating with the pulmo- 

 nary lymphatic vessels near the roots of the lungs, terminate in the thoracic duct 



