THE LYMPHATICS OF THE THORAX S03 



A knowledge of the lymphatics of the breast and of the nodes into which the lymphatics drain 

 is of the first importance to a surgeon. Certain surgical deductions from the anatomy of this 

 region are perfectly obvious viz.: (1) If the skir/of the mammary gland is involved in carci- 

 noma, the thoracic group of axillary nodes of the same side is involved. If the skin over the 

 sternal margin of the gland is involved, the nodes of the opposite axilla may be cancerous, as 

 from this point lymph vessels rise and pass across the midline. If the skin of the sternal margin 

 is involved the prognosis is worse than if it is free, the opposite axilla may be cancerous, and the 

 opposite breast may become diseased. (2) When lymphatic vessels become blocked by cancer 

 cells the lymph backs up, flows backward instead of in its proper direction, and may cause infec- 

 tion in the most unsuspected situations. For instance, a block in the cutaneous lymphatics of 

 a portion of the breast may lead to infection of the opposite breast and axilla, though, of course, 

 it is not so likely to as is cancer of the skin of the sternal margin. By regurgitattoa of lymph 

 the head of the humerus or the retrosternal structures tnay become diseased in mammary cancer. 

 (3) If the nipple or areola is cancerous, the entire gland is sure to be diseased, as the lymphatic 

 network of this region empties into the subareolar plexus, and most of the trunks coming from 

 the gland also enter this plexus. (4) If the mammary gland is cancerous, all of the axillary 

 nodes are regarded as diseased, as the main lymphatic channel from the breast reaches the 

 nodes on the inner wall of the axilla upon the third digitation of the Serratus magnus. Further- 

 more, in many cases an accessory lymph channel comes off from the lower portion of the mam- 

 mary gland and passes directly to the axilla. (5) The subclavian nodes are to be regarded 

 as diseased, because in a certain proportion of cases (the exact proportion being uncertain) an 

 accessory lymph channel comes off from the posterior surface of the mammary gland, passes 

 through the great Pectoral muscle, and ascends between the greater and lesser Pectorals to reach 

 the subclavian nodes. (6) The element which greatly interferes with the cure of mammary 

 carcinoma is the existence of lymph channels which arise from the inner portion of the mam- 

 mary gland, pierce the greater Pectoral and Internal intercostal muscles, and reach the internal 

 mammary nodes. Mediastinal involvement is apt to be earlier in carcinoma of the inner por- 

 tion of the breast than in carcinoma of .other portions, and the prognosis is particularly bad 

 in cancer of the inner portion of the breast. What is known as the sternal symptom of Snow is 

 bulging of the sternum due to involvement of the thymus gland. (7) The sternal portion of 

 the great Pectoral and the tissue between it and the lesser Pectoral muscle are to be regarded 

 as diseased, because in some cases an accessory lymph channel from the breast penetrates the 

 greater Pectoral and ascends to the subclavian nodes. This trunk has several interrupting or 

 satellite nodes, the rctropectoral nodes, in the tissue back of the great Pectoral muscle. (8) 

 When the great Pectoral muscle is diseased, cancer cells soon spread widely through the sternal 

 portion of the muscle, and this entire portion of the muscle becomes cancerous. The clavicular 

 portion does not suffer early, but escapes until the cancer becomes extensive, as it is anatomically 

 distinct from the sternal portion. If the fibres of the great Pectoral are extensively diseased, 

 the thoracic group of axillary nodes, the subclavian nodes, and possibly the internal mammary 

 nodes are involved. (9) The only operation in cancer of the breast which offers any real hope 

 of cure is one which is done early and is radical. (10) It must be done early, because delay 

 permits involvement of the mediastinum, and if the disease has entered the mediastinum opera- 

 tion is hopeless. If the sternum is bulged operation is useless, and nothing short of amputation 

 at the shoulder-joint could be of help if the head of the humerus is enlarged by the disease. 

 Even this radical procedure is of no avail, because the mediastinum is certainly involved if the 

 head of the humerus is diseased. (11) If the lymph nodes above the clavicle are extensively 

 diseased operation is useless, as in such cases the mediastinum is sure to be involved. (12) A 

 radical operation means the removal of the skin of the breast with the nipple and areola, the 

 subcutaneous tissue of this region, the entire breast, the sternal portion of the great Pectoral 

 with its fascia, the retropectoral nodes and tissue, all the contents of the axilla except vessels 

 and nerves, the nodes and cellular tissue beneath the anterior margin of the Latissimus dorsi, 

 and the subclavian nodes. It is probably always wisest to open above the clavicle as well as 

 below to facilitate the removal of nodes. It is seldom necessary to remove the clavicular por- 

 tion of the greater Pectoral. The lesser Pectoral does not require removal, but it should be taken 

 away, because of the added safety and speed thus obtained in cleaning the great vessels and 

 because its retention does not improve the functional result. The surgeon must remember that 

 the breast is a much larger organ than we used to think, and all of its irregular projections and 

 outlying lobules must be removed (p. 787). Formerly, surgeons did not completely remove 

 the breast, but only got rid of a large portion of it. 



The visceral lymph nodes consist of three groups viz., anterior mediastinal, 

 posterior mediastinal, and tracheobronchial. 



The anterior mediastinal nodes (lymphoglaiidulae mediastinales anterwreti) are 

 placed in the antenior part of the superior mediastinum, in front of the arch of 

 the aorta and in relation to the innominate veins and the large arterial trunks 



