230 



LYMPHATIC AND LACTEAL SYSTEM. 



are received into the principal branches. These 

 latter pass upwards in front of the transverse 

 vein, to empty themselves on the left side into 

 the termination of the thoracic duct; on the 

 right, into the right lymphatic trunk, or they 

 join the large veins separately, close to the en- 

 trance of the two trunks of the system. 



The lymphatics of the lungs are of large 

 size, and are divided, as in other parts of 

 the body, into a superficial and deep-seated 

 set. The latter accompany the ramifications 

 of the bloodvessels and air-tubes throughout 

 the texture of the organ, and communicate at 

 various points with the superficial vessels. The 

 principal branches escape from the lung at its 

 root, where they are joined by the superficial 

 vessels, and pass with them through the large 

 bronchial glands. The superficial lymphatics 

 of the lung are larger than those of any other 

 viscus ; they are situated in the interlobular 

 fissures immediately under the pleura, and are 

 injected with greater facility than the lymphatics 

 of other parts of the body; their principal 

 branches pass from the surface of the lung 

 towards the inner edge and root of the organ, 

 where they unite with the deep-seated ves- 

 sels, and pass with them through the bron- 

 chial glands. The vasa erTerentia of these 

 glands having communicated with the glands 

 in the posterior mediastinum pass upwards on 

 the trachea, where they meet with other glands 

 with which they interchange branches; having 

 entered the cervical region with the trachea, 

 they unite freely with other lymphatics, espe- 

 cially with those of the thyroid gland, and 

 ultimately terminate, on the left side, in the 

 thoracic duct; on the right, in the right lym- 

 phatic trunk, or separately in the large veins. 



The lymphatics of the heart are neither large 

 nor numerous ; they proceed both from the sub- 

 stance and from the surface of the organ ac- 

 companying the principal bloodvessels; their 

 appropriate glands are chiefly situated on the 

 ascending thoracic aorta and trunk of the pul- 

 monary artery ; where these vessels are covered 

 by the pericardium, they ascend in front of the 

 arch of the aorta, pass between the sternum 

 and transverse veins, communicate freely with 

 the large vessels of the anterior mediastinum, 

 and terminate with them on either side in the 

 trunks of the system, the greater number, 

 however, passing on the left sides to the tho- 

 racic duct. 



The deep-seated lymphatics of the upper ex- 

 tremity successively accompany the digital arte- 

 ries, the superficial and deep palmar arches, 

 the radial, ulnar, and interosseous arteries. At 

 least two lymphatic vessels accompany each ar- 

 tery ; they communicate by short transverse 

 branches with each other, and also at different 

 points with the superficial lymphatics. At the 

 bend of the elbows they unite into three or four 

 vessels which pass up the arm with the bra- 

 chial artery to gain the axillary glands, into 

 which they empty themselves. The small 

 glands which not unfrequently may be found 

 accompanying the brachial artery, and even, 

 but more rarely, the ulnar or radial vessels do 

 not generally intercept the deep lymphatic 



Fig. 57. 



a 



Superficial lymphatics of the upper extremity. 



( After Maacagni. ) 



a, a, Commencing lymphatic vessels ascending 

 in the forearm with branches of the median vein. 



6, c, d, The continuations of the vessels similarly 

 marked in the former woodcut. 



e, A vessel passing from the posterior to the an- 

 terior surface of the arm over its outer edge. 



f, Branches of the basilic vein. 



g, Cephalic vein. 

 h, Axillary glands. 



i, Two small glands situated above the internal 

 condyle. 



vessels, but the latter rather receive the efferent 

 vessels from these glands, they having collected 

 their afferent vessels from the surrounding tex- 

 tures. 



