The Thorax. 115 



anterior set of the axillary glands, and then on, towards 

 the set around the axillary vein. Some, piercing the in- 

 tercostal muscles go to the thoracic duct in the posterior 

 mediastinum, while others, entering the anterior media- 

 stinum through the second and fourth interspaces, pass 

 through glands in this mediastinum and, after communi- 

 cating with the lymphatics ascending from the surface of 

 the liver, empty into the junction of the internal jugular 

 and the subclavian veins. This arrangement of the lym- 

 phatics explains the dissemination of malignant disease 

 to the axilla when the outer quadrant of the breast is 

 affected, and the possible involvement of the ribs, pleura 

 and liver, when the inner quadrant is diseased. Gross 

 states, that, out of 128 post-mortems, the axillary glands 

 were affected in 90%, the pleura in 23%, and the liver in 

 43% (some of the subjects having more than one region 

 affected). The dimpling and puckering of the skin in 

 mammary cancer is due to the disease extending along the 

 ligamenta suspensoria, and the subsequent contraction of 

 the newly- formed fibrous tissue. The rich lymphatic sup- 

 ply of the mammary gland and the early involvement 

 thereof, warrant Halsted's operation a very radical pro- 

 cedure and consisting of the complete removal of all the 

 tissues of this region down to the ribs. The nerves sup- 

 plying the gland are the anterior thoracics, the anterior 

 divisions of the lateral cutaneous branches of the inter- 

 costals, the terminations of the intercostals, a few fila- 

 ments of the supraclavicular nerve, twigs from the 

 fourth, fifth and sixth intercostal trunks to the deep sur- 

 face of the gland, and, lastly, the sympathetic. This ner- 

 vous distribution explains the reference of the pain in 

 mastitis, or inflammation of the mammary gland, to the 

 region of the sternum in front (anterior divisions of the 

 intercostal nerves) ; to the area over and between the scap- 



