THE LYMPHATICS OF THE LOWER EXTREMITY. 995 



Popliteal abscess will follow pyogenic infection of the popliteal nodes. The 

 pressure effects due to the density and rigidity of the popliteal fascia and the conse- 

 quent necessity for early and free incision and drainage have already been described 

 (pages 646). Enlargement of the popliteal nodes has been mistaken for enlarged 

 bursse — though the nodes are deeper and nearer the median line— for popliteal aneur- 

 ism, and for neoplasms. 



The inguinal nodes are numerous and, on account of their frequent involvement 

 in diseases of the lower extremity and of the genitals, are important. The arrange- 

 ment into a superficial and deep set, and the division of the former into two groups, 

 the horizontal, parallel with and close to Poupart's ligament, and the vertical, p2iX2i\\e\ 

 with and close to the long saphenous vein, is of convenience. The deep set is found 

 to the inner side of the femoral vein and may be said to include one group which is 

 embedded in the fatty layer at the saphenous opening and bears the same relation to 

 the fascia lata that the central group of axillary glands bears to the axillary fascia 

 (Leaf) (page 581). The inguinal nodes receive lymph through the superficial lym- 

 phatics as follows : Lower limb — vertical set of superficial nodes ; lower half of 

 abdomen— middle nodes of horizontal set ; outer surface of buttock — external nodes 

 of horizontal set ; inner surface of buttock — internal nodes of horizontal set, (a few 

 of these vessels go to the vertical nodes ; external genitals — horizontal nodes, a few 

 going to the vertical set ; perineum-vertical set. The deep lymphatics of the^ lower 

 limb enter the deep set of nodes (Treves). The deep lymphatics of the penis and 

 those that are found with the obturator, gluteal, and sciatic vessels enter the pelvic 

 nodes. The inguinal nodes communicate with the external and common iliac nodes, 

 the pelvic lymphatics with the internal iliac nodes, and both the iliac groups with the 

 lumbar nodes. The deep node lying in the crural canal and upon the septum crurale 

 is variously described as one of the obturator (pelvic) group (Leaf) and as one of 

 the deep set of inguinal nodes (Treves). It should be remembered that when it is 

 inflamed it may not only simulate strangulated hernia, but, on account of the density 

 of the structures by which it is surrounded and their participation in the movements 

 of the thigh, may give rise to pain suggesting coxalgia. 



The relations 'of branches of the anterior crural nerve to the inguinal nodes 

 may, in cases of inflammation or enlargement, give rise to pain or spasm in the region 

 supplied by that nerve. Filariasis (elephantiasis arabum) of the femoral lymphatics, 

 which are obstructed by the worms, gives rise to very great swellmg of the lower 

 extremity (Cochin leg, Barbadoes leg). 



In addition to what has been stated above the practical application of a knowl- 

 edge of the lymphatics of the lower extremity embraces the following considerations : 



(«) The lymphatic vessels may be inflamed without involvement of the veins, 

 when the course of some of the main vessels can be distinctly traced under the skin. 

 When chronically inflamed, and obstruction exists at the nearest lymphatic gland, the 

 vessels may become thickened, dilated, and tortuous. The lymphatic vessels of the 

 sheath of the penis are, perhaps, more frequently involved in diseased action than 

 those of any other portion of the skin surface. Inflamed lymphatic vessels often 

 co-exist with a chancre. In cases of neglected chancre, associated with an indurated 

 condition of the lymphatic nodes of the groin, they may even form buUa-like swell- 

 ings which sometimes rupture and permit the lymph to escape externally. Rarely 

 dilatation of the lymphatic vessels occurs without apparent cause. 



{b) The lymphatic vessels may, from causes imperfectly understood, become 

 filled with chylous fluid. In one (Petters), remarkable dilatation of the lymphatics 

 existed in the right groin and in the abdomen, in a patient the subject of valvular 

 heart disease. The glands were converted into cyst-like cavities filled with a yellow 

 fluid. Rosary-like dilatations, similar to those seen at the elbow, occur infrequently 

 below the groin. 



The inguinal lymphatic glands are the common seat of diseased action dependent 

 upon the transmission of the virus of syphilis, or of any other irritant whose point of 

 entrance is through the external genitals. In the nonsyphilitic infections they 

 frequently suppurate or excite suppurative cellulitis in the parts about them. Acute 

 inflammatory engorgement of one of them has been known to induce fatal peritonitis 

 by direct continuity through the lymphatic vessels of the abdominal wall (Allen). 



