2036 HUMAN ANATOMY. 



central group of nodes lies on the deep surface of the axillary fascia, forming one 

 large group with it. Involvement of these nodes with their afferent lymph vessels 

 probably accounts for the extensive infiltration of the structures over the upper 

 lateral and posterior aspects of the thoracic parietes occasionally seen in advanced 

 cases. 



3. The nodes at the summit of the axilla may be involved through lymph vessels 

 passing above the pectoralis minor and through Mohrenheim's fossa without entering 

 the pectoral nodes. 



4. The anterior mediastinal glands may be invaded — especially if the inner 

 segment of the breast is affected — by way of the lymph vessels following the per- 

 forating arteries and emptying into the nodes along the internal mammary artery. 

 In this manner, as well as by direct extension through the inframammary tissue, the 

 pectoral fascia and muscles, and the chest wall, the pleura and lung may become 

 invoked. Other symptoms due to mediastinal growth have been described in rela- 

 tion to that region (page 1833). 



5. The free communication in the subareolar plexus between the glandular 

 lymphatics, deep and superficial, (paramammary) and the subcutaneous and thoracic 

 lymphatics, together with the connection established between the periglandular 

 tissue below and the skin above by the ligaments of Cooper (suspensory ligaments), 

 explains the frequency with which mammary carcinoma extends to the overlying 

 skin. As a result of its infiltration the latter becomes dense, inelastic, brawny, 

 dusky, and adherent. It cannot be picked up between the thumb and finger in a 

 fold; and often quite early and before it has become adherent, and as a result of con- 

 traction of the growth pulling on the fibrous bands uniting it to the deeper parts, it 

 is drawn into a number of little depressions or dimples like those on the skin of an 

 orange. When such infiltration is diffuse and spreads largely through the subcu- 

 taneous net-work of lymph vessels, the condition known as cancer en cuirasse is pro- 

 duced. In the later stages ulceration, infection, hemorrhage, and foul discharge are 

 frequent results of the cutaneous involvement. 



6. If the growth is central it may extend to the lactiferous ducts or to the peri- 

 acinous tissue continuous with that surrounding the ducts, and through its own or 

 their cicatricial contraction it may depress or retract the nipple or pull it so that it 

 deviates from its normal direction. This is not so valuable a symptom as the dim- 

 pling of the skin above described, as it may be caused by injury or by chronic disease, 

 such as abscess, tubercle, or mastitis. Moreover, it may not be present if the growth 

 is peripheral. 



7. The carcinoma may extend through the lymph communications between the 

 gland and the underlying connective tissue and pectoral fascia and muscle, so as to 

 become fi.xed to or incorporated with those structures, the breast losing much of its 

 mobility, especially in a direction parallel with the pectoralis major fibres. It may 

 thence continue through the thoracic wall and invade the pleural or mediastinal cavity 

 directly. 



8. Through the intercommunication of the lymph system of the two breasts 

 through the subcutaneous thoracic lymphatics, cancer of one breast may extend to the 

 other (Moore), or to the glands of the opposite axilla (Volkmann, Stiles), or to the 

 glands of both axillae fScarpa, Cooper ; quoted by Williams). 



9. General dissemination of the cancerous disease may also take place through 

 detached cells or particles (emboli) from the primary growth entering the blood 

 stream. The liver is the organ most frequently affected by metastasis in cases of 

 breast cancer. The bones, the lungs, and the pleurae come next, but almost no 

 organ or structure of the body is exempt. 



In removal of the breast the following anatomical points should be borne in mind : 

 (a) The intimate connection between the skin and the gland itself by means of lymph- 

 and blood-vessels, by the suspensory ligaments, and by glandular processes accom- 

 panying or contained within these ligaments (Stiles), shows the necessity for free 

 sacrifice of the skin overlying the breast. 



(b) The irregular shape of the breast, which has two extensions that frequently 

 reach into the axilla, and one that reaches to or overlaps the border of the sternum, 

 and not uncommonly similar processes that spring from other parts of the surface of 



