636 THE LYMPHATIC SYSTEM 



caecum, ascending and transverse colon, which, after passing through their proper 

 glands, enter the mesenteric glands ; and those of the descending colon, sigmoid 

 flexure, and rectum, which pass to the lumhar glands. 



THE LYMPHATICS OF THE THORAX. 



The Lymphatic Glands of the Thoracic Wall are the intercostal, internal mam- 

 mary, anterior mediastinal, and posterior mediastinal. 



The intercostal glands are small, and situated on each side of the spine, near 

 the costo- vertebral articulations ; they vary from one to three in each space. 



The sternal or internal mammary glands are placed at the anterior extremity 

 of each intercostal space, by the side of the internal mammary vessels. 



The anterior mediastinal glands are placed in the loose areolar tissue of the 

 anterior mediastinum, some lying upon the Diaphragm in front of the pericardium, 

 and others round the great vessels at the base of the heart. 



The posterior mediastinal glands are situated in the areolar tissue in the poste- 

 rior mediastinum, forming a continuous chain by the side of the aorta and oesoph- 

 agus ; they communicate on each side with the intercostal, below with the lumbar, 

 and above with the deep cervical glands. 



The Superficial Lymphatic Vessels 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 greater part of the mammary gland pass outward to the 

 lower border of the Pectoralis major muscle, where they enter a chain of small 

 glands situated in the axillary space along the lower border of its anterior 

 boundary. Some few lymphatics from the inner side of the mammary gland pass 

 through the intercostal spaces to reach the anterior mediastinal glands. 



The Deep Lymphatic Vessels of the Thoracic Wall are the intercostal, internal 

 mammary, and diaphragmatic. 



The intercostal lymphatic vessels follow the course of the intercostal vessels, 

 receiving lymphatics from the intercostal muscles and pleura ; they pass backward 

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

 canal. After traversing the intercostal glands, they pass down the spine and 

 terminate in the thoracic duct. 



The internal mammary lymphatic vessels 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 ensiform appendix, and in their 

 course behind the costal cartilages are joined by the intercostal lymphatics; they 

 terminate on the right side in the right lymphatic duct, on the left side in the 

 thoracic duct. 



The lymphatic vessels of the Diaphragm follow the course of their correspond- 

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

 mammary glands, some behind, in the intercostal and posterior mediastinal lymph- 

 atics. 



The Lymphatic Glands of the Viscera of the Thorax are the bronchial 

 glands. 



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 situations ; 

 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 tuberculous deposits. 



The superior mediastinal or cardiac glands lie in front of the transverse aorta 



