774 



THE VASCULAR SYSTEMS 



In an operation for cancer it is not sufficient to cut wide of the growth and remove it; it is 

 imperatively necessary to remove the lymph nodes which receive lymph from the diseased 

 area, and also, when possible, the lymphatic vessels between the cancer and the nodes. Nodes 

 are diseased very early in cancer, long before they are palpably enlarged, and are usually infected 

 . . by emboli of cancer cells. The 'rule is in 



any cancer, however recent, to regard the 



Right Vfl>!i*; associated nodes as diseased, whether en- 



lymphatic ^mlm f iia IW-lfm lai> g ed or n t, and to remove them thor- 



duct. ^/tt mm. f fl'J :.Er_hlH$ oughly, if possible, in one piece, with the 



intervening lymph vessels and the area of 

 primary malignant growth. 



THE THORACIC DUCT. 



The thoracic duct (ductus thorac- 

 icus} (Fig. 552) conveys the great 

 mass of lymph and chyle into the 

 blood. It is the common trunk of 

 all the lymphatic vessels of the body, 

 excepting those of the right side of 

 the head and neck, the right upper 

 extremity, the right lung, right side 

 of the heart, and part of the convex 

 surface of the liver. In the adult 

 it varies in length from fifteen to 

 eighteen inches, and extends from 

 the second lumbar vertebra to the 

 root of the neck. It commences in 

 the abdomen by a triangular or fusi- 

 form dilatation, the receytacuhim 

 chyli. which is situated 

 front of the bodies of the first and 

 of the second lumbar vertebrae, to 

 the right side and behind the aorta. 

 overlapped by the right crus of the 

 Diaphragm. It enters the thorax 

 through the aortic opening in the 

 Diaphragm, lying to the right of 

 the aorta, and is then placed in 

 the posterior mediastinum between 

 the aorta and vena azygos major. 

 Here it lies in front of the vertebral 

 column, from which it is separated 

 by the right intercostal arteries, 

 and by the azygos minor veins as 

 they cross the middle line to open 

 into the vena azygos major. Op- 

 posite the fifth thoracic vertebra it 

 inclines toward the left side, enters 

 the superior mediastinum, and 



FIG. 552. The thoracic and right lymphatic ducts. 



ascends behind the arch of the aorta 

 on the left side of the oesophagus, and behind the first portion of the left sub- 

 clavian artery, to the upper opening of the thorax. Opposite the seventh cervical 

 vertebra it turns outward in front of the vertebral artery and vein, behind the left 

 common carotid artery and vagus nerve, and -then curves downward over the 



