THE LYMPHATICS OF THE UPPER EXTREMITY. 961 



to be of lymphatic origin, because (a) they are often associated, and sometimes 

 anatomically connected with other congenital defects of the lymphatic system, 

 such as niacroglossia (cavernous lymphangioma of the tongue) and macrocheilia 

 (labial lymphangioma) ; and {&) they are in communication with the lymphatic 

 trunks (Rolleston). 



THE LYMPHATICS OF THE UPPER EXTREMITY. 



The Lymphatic Nodes. 



The lymphatic nodes of the arm are for the most part confined to its upper 

 portions, the principal group occurring in the axilla and consisting of a considerable 

 number of nodes united by connecting stems to form a plexus axillaris. A few 

 scattered nodes also occur in the brachial region and some are occasionally to be 

 found in the antibrachium, but they are entirely lacking in the hand. An especial 

 interest attaches to the axillary nodes on account of the extensive area from which 

 they receive aflterents, for, in addition to almost the entire lymphatic drainage of the 

 arm, they also receive the vessels from the anterior and lateral thoracic walls, from 

 the mammary gland, and from the scapular region. The brachial and antibrachial 

 nodes, on the other hand, are rather to be regarded as "intercalated" nodes inter- 

 posed in the course of certain of the lymphatic vessels ; some of them lie superficial 

 to the deep fascia, while others are situated more deeply along the course of the 

 principal blood-vessels, and, consequently, it is convenient to divide them into two 

 sets according as they are superficial or deep. 



The superficial brachial nodes (lymphoglandulae cubitales superficiales) are 

 arranged in two principal groups. One of these rests upon the brachial fascia imme- 

 diately over the internal condyle of the humerus, and may be termed the epitrochlear 

 group (Fig. 809). It consists of from one to four nodes, of which one, the lowest of 

 the group, is especially constant and is termed the epitrochlear node. The remaining 

 nodes, if present, are situated along the course of the basilic vein, one frequently 

 lying almost in the median line of the arm a short distance above the bend of the 

 elbow. The ajferents of the epitrochlear nodes are the superficial vessels of the 

 forearm and hand, especially those which pass upward along the ulnar border of 

 the forearm ; their efferents pass upward along the basilic vein and join the deep 

 vessels where the basilic vein dips down to join the brachial. 



A second group, which may be termed the delto-pector'al group, consists of from 

 one to four nodes situated, along the course of the cephalic vein, in the groove 

 between the deltoid muscle and the clavicular portion of the pectoralis major 

 (Fig. 8og). They are not always distinguishable and are usually quite small. 

 They are interposed in the course of the delto-pectoral lymphatic stem which passes 

 upward in the groove and opens into the subclavicular group of axillary nodes 

 or opcasionally into the inferior deep cervical nodes. 



The deep brachial nodes sometimes include some small nodes occurring on 

 the lymphatic stems which accompany the ulnar and radial blood-vessels, but these 

 nodes are relatively inconstant. Of more frequent occurrence is a group of two 

 or three small nodes (lymphoglandulae cubitales profundae) which occur upon the stems 

 accompanying the brachial artery and are situated at about the middle part of its 

 course. Their afferents are the deep lymphatics of the forearm and their efferents 

 pass upward to terminate in the humeral nodes of the axillary group. 



The axillary nodes, which are embedded in the areolar tissue occupying the 

 axillary space, vary in number from si.xteen to thirty-six. Some of them are usually 

 of considerable size, especially in those cases in which their number approaches the 

 lower limit mentioned, for it is a general rule that the size of the nodes in any group is 

 inversely proportional to their number ; but it seems probable that in addition to those 

 which may be observed macroscopically, exceedingly small ones, approaching micro- 

 scopic size, also occur, and that these, under pathological conditions or after removal 

 of the larger ones, may increase in size and form additional or new foci of infection. 



Although united by connecting stems to form a plexus, the axillary nodes m.ay 

 be divided, according to their position and the source from which their af?erents 

 come, into a number of more or less distinct subgroups (Figs. 808, 814), and of 



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