PRACTICAL CONSIDERATIONS: MAMMARY GLANDS. 2035 



ward from the nipple so that the larger lactiferous ducts converging to that point 

 may not be wounded. 



Carcinoma of the breast is the most important of the diseases affecting that 

 gland, about 85 per cent, of the neoplasms involving the female mamma being can- 

 cerous. About 99 per cent, of all neoplasms of the breast occur in the female, only 

 i per cent, in the male, " illustrating the law of which many other instances might 

 be cited that functionless, obsolete structures have but little tendency to take on 

 the neoplastic process" (Williams). It begins most often in the cuboid (glandular) 

 epithelium of the alveoli acinous cancer ; but not uncommonly in the columnar 

 epithelium of the ducts duct cancer. In either case it is usually at first a dense 

 nodule of small size, growing by infiltration of the neighboring tissues. In tracing 

 the methods of extension and dissemination from the original nodule in the gland 

 substance, the various structural relationships must be borne in mind. The ana- 

 tomical routes along which such a growth may spread, and the chief symptoms 

 thereby produced, are as follows : 



1. By way of the lymphatic vessels that empty into the lymph nodes (pectoral 

 or anterior) overlying the digitation of the serratus magnus arising from the third 

 rib. This is the most frequent form of lymphatic dissemination, because (#) these 

 vessels include the great majority of the mammary lymphatics ; (b) the nodes first 

 involved in cancer are those into which is emptied the lymph from the part of the 

 gland affected by the primary growth ; and (c) cancer originates most frequently in 

 the upper and outer quadrant of the breast, possibly because that area is most 

 exposed to minor traumatism ; or possibly because the alveoli are much more 

 numerous in the peripheral than the central part of the gland, the majority of mam- 

 mary neoplasms arising in the seats of the greatest development of postembryonal 

 activity where cells still capable of growth and development most abound (Williams) 

 i.e., in the vicinity of the alveoli. Williams calls attention to the fact that the 

 " axillary tail" of the mamma lies close to the pectoral nodes and might be mistaken 

 for the enlarged gland. By placing the flat of the hand or the palmar surfaces of 

 the fingers against the inner (thoracic) wall of the axilla and moving the superficial 

 structures to and fro, enlargement of the pectoral nodes may easily be detected. 



2. From these pectoral nodes situated along the anterior border of the axilla, 

 carcinoma may invade (a) the central nodes, receiving the lymph from the upper 

 extremity, and lying on the inner side of the axillary vein, on either the superfi- 

 cial or deep aspect of the axillary fascia, embedded in a quantity of fat, and half- 

 way between the anterior and posterior folds of the axilla. The inner portion of the 

 axillary tuft of hair overlies this group of glands. The axillary fascia at this place 

 may present an opening very similar to the saphenous opening of the thigh (Poirier, 

 Leaf) and the nodes may occupy this. These nodes may be palpable, but if only 

 slightly enlarged cannot readily be felt in stout persons. If no axillary opening is 

 present and the nodes lie on the superficial aspect of the fascia, they can best be felt 

 by pressing them against the unyielding fascia, with the arm in the abducted posi- 

 tion ; if, on the other hand, an opening is present, the arm should be adducted so 

 as to relax the fascia, when the nodes may be recognized by pressing them against 

 the thoracic wall. For these reasons, in examining for enlarged axillary nodes, the 

 arm should always be placed in both these positions (Leaf). As this set of nodes is 

 traversed by the intercosto-humeral nerve, carcinoma involving them often causes 

 pain down the inner and posterior aspect of the arm. As they receive the lymph 

 vessels of the upper limb, the structures in the deltoid region and down the arm may 

 become infiltrated. Or the disease may invade () the deep axillary nodes, lying 

 along the inner and anterior aspect of the axillary vessels, and communicating with 

 both the pectoral and the lower deep cervical nodes; extensive implication of this group 

 results in oedema and swelling of the upper limb, compression of the axillary vein, and 

 in widely distributed pain in the regions supplied by the brachial plexus; (c] the infra- 

 clavicular (cephalic) nodes, lying just below the clavicle, between the deltoid and pec- 

 toralis major muscles and, like the deep axillary nodes, communicating below with 

 the pectoral nodes, and above with the supraclavicular or inferior cervical nodes, the 

 disease often reaching these latter ; (</) the subscapular nodes, lying along the sub- 

 scapular vessels and receiving lymph from the scapular region, and often, when the 



