THE LYMPHATICS OF THE THORAX. 



969 



around it, perforate the axillary fascia, and terminate in the anterior pectoral nodes 

 of the axillary plexus. Occasionally one finds along the course of one or other of the 

 stems a small intercalated node, and one or two small nodes, the paramammillaiy 

 nodes, may occur a short distance below the lower border of the gland on one of the 

 efferents which passes to the lower principal stem. 



The accessory paths of the mammary lymph are principally two in number, 

 r I ) In about ten per cent, of cases examined a stem issued from the deep surface of 

 the gland, perforated the pectoralis major, and passed upward between that muscle 

 and the pectoralis minor to terminate in the subclavicular nodes. (2) A varying 

 number of small stems leave the medial portion of the periphery of the gland and 

 perforate the sternal border of the pectoralis major and the intercostal muscles, to 

 terminate in the sternal nodes. 



It may be noted that the obstacle to the flow of lymph presented by enlarged axillary nodes 

 in severe affections of the mammary gland may lead to the development of accessory or 

 collateral paths other than those mentioned above. Thus, since the subareolar net-work is 



Delto-pectoral node 



Fig. S14. 



Brachial node 



Subclavian node 



Subscapular node 



Anterior pectoral node \i. 



Vessel passing to anterior 



pectoral node 



Vessel passing to 

 subclavian node 



Intermediate node 



Inferior pectoral node 



Subareolar plexus 

 over maminary 

 gland 



Lymphatics of mammary gland and axillary nodes. (Poirier and Cuneo.*) 



continuous with the general anterior thoracic subcutaneous net-work, and the latter is continuous 

 across the median line, affection of the gland of one side may cause enlargement of the axillary 

 nodes of the opposite side, and, furthermore, since the thoracic subcutaneous net-work is 

 continuous with that of the abdomen, there is a possibility for the establishment of a collateral 

 path leading to the inguinal nodes. 



Furthermore, it is to be remembered that, although the anterior pectoral nodes are the 

 termination of the principal mammary stems, yet the connection between these and other 

 axillary nodes, especially those of the intermediate and subclavicular subgroups, is so intimate 

 that practically all the axillary nodes may be involved, or are at least open to suspicion, in 

 cases of mammary carcinoma. 



The intercostal lymphatics are arranged in two sets corresponding to the 

 two intercostal muscles (Sappey). The vessels from each internal intercostal unite to 

 form a single stein which passes forward along the lower border of the rib forming 

 the upper boundary of its space. The stems of the upper spaces open independently 

 into the sternal nodes, while those from the lower spaces unite to form a common 

 ascending stem which terminates in the lowest node of the sternal chain. 



* Poirier et Charpy : Traite d'anatomie humaine, Tome ii., 1902. 



