THE LYMPHATICS OF THE UPPER EXTREMITY. 



963 



come from the integument and muscles of the lower part of the neck, from the 

 dorsal surface of the thorax, and from the scapular region ; the effereyits pass mainly 

 to the nodes of the intermediate subgroup. 



5. The intermediate subgroup consists of a number of rather large nodes 

 imbedded in the adipose tissue which occupies the interval between the lateral wall 

 of the thorax and the upper part of the long thoracic vein as it bends outward to 

 open into the terminal part of the axillary vein. It receives afferents from all the 

 terminal subgroups of the axillary plexus, and its effcrents pass to the nodes of the 

 subclavicular subgroup. 



6. The subclavicular subgroiip consists of from six to twelve nodes situated 

 near the apex of the axillary space, partly beneath the pectoralis minor and partly 

 above the upper border of that muscle. They constitute the final link in the 

 axillary chain, since they receive as affereyits, either directly or indirectly through the 

 intermediate nodes, the efferents from all the other subgroups. Their efferents unite 

 to form a trunk of considerable size, the subclavian trunk (truncus subdavius), 

 which, from its origin opposite the lirst intercostal space, passes almost vertically 

 upward over the subclavian vein to open into it near its junction with the <?xi:ernal 

 jugular, or else to unite with the jugular trunk on the right side or .0 open into the 

 arch of the thoracic duct, on the left side. In addition to this principal termination 

 one or more of the subclavicular efferents usually pass to one of the lower nodes of 

 the interior deep cervical group. 



The independent termination of the subclavian trunk in the subclavian vein is probably the 

 most frequent arrangement, but the e.xact position of its junction with the vein is variable. Most 

 frequently it empties at the angle formed by the junction of the subclavian and internal jugular 

 veins, but it may terminate upon the superior surface of the subclavian vein some distance ( i cm. ) 

 away from the angle, and quite frequently it opens upon the anterior surface of the vein, or, in 

 rarer instances, upon its posterior surface. Not unfrequently two or even more subclavian 

 trunks occur, and in such cases one may unite with the jugular trunk, or, if on the left side, open 

 into the arch of the thoracic duct, while the other terminates directly in the vein. 



Delto-pectoral 

 node 



The Lymphatic Vessels. 



The lymphatic vessels of the upper limb are divisible into two groups according 

 as they lie superficial to or beneath the deep fascia. 



The superficial vessels, which are far more numerous than the deep ones, have 

 their origin in the subcutaneous net-work which occurs throughout 

 the entire extent of the limb, but is especially developed upon the ^^^- ^°9- 



palmar surface of the hand and upon the fingers (Fig. 8ioj. The ^ 



net-work of each digit tends toward its sides and at its base unites V- 

 with those of the adjacent digits to form a number of 

 stems which pass upward upon the dorsal surface of the 

 hand, for the most part over the intermetacarpal spaces, 

 although abun- 

 dant anasto- 

 moses occur 

 between the 

 vessels of 

 neighboring 

 spaces so that 



an open dorsal net-work is formed. The 

 stems which arise from the net-works of the 

 inner border of the little finger and of the outer border of the 

 index also pass upward upon the dorsum of the hand, lying 

 respectively toward its inner and outer borders, and the net- 

 work of the thumb is drained by vessels which pass upward 

 on its dorsal surface. From the central portion of the palmar 

 net-work some small stems pass deeply, penetrating the 

 palmar aponeurosis to join the deep lymphatic vessels, but 

 its remaining portions radiate in all directions to join the 

 stems of the dorsal net-work. Thus, the distal portions of the net-work converge 



Superficial lymphatic vessels of 

 upper limb; semidiag:rammatic. 

 (leased on figures of Sappey.) 



