91 8 HUMAN ANATOMY. 



The internal iliac veins may become involved in infections of any of the 

 numerous plexuses from which their tributaries arise. Thus, puerperal metritis 

 mav not only lead to pelvic cellulitis (page 2014), but may set up a thrombo-phlebitis 

 in the intra-uterine veins which, spreading to the internal and common iliac veins, 

 will obstruct the venous current from the whole lower extremity, bringing about a 

 wide-spread oedema, with aching and tenderness (phlegmasia alba dolens, milk leg). 

 Similar conditions sometimes follow septic infection of the prostatic vesical and 

 hemorrhoidal plexuses. The practical relations of these venous channels have been 

 described in connection with the prostate, bladder, and rectum. The branches 

 of the internal iliac vein aid indirectly in supporting the pelvic viscera. They are 

 apt to be varicose in the aged, especially in females. They supply the blood in 

 cases of pelvic haematocele. 



The external iliac vein is frequently involved in femoral phlebitis, the 

 continuity of direction and calibre between it and the femoral being practically 

 unbroken. 



The femoral vein is not infrequently the subject of thrombo-phlebitis, descend- 

 ing, as a result of some form of pelvic infection {vide supra), or ascending, following 

 septic infection of the soft parts or bones of the lower extremity ; or occasionally 

 directly caused by contusion of the vessel just below the groin, or by its bruising 

 during forced flexion of the thigh. Femoral phlebitis is not uncommonly a sequel 

 of enteric fever and of other exhausting diseases, and is a familiar post-operative 

 complication of operations for the removal of the appendix, the uterus, the tubes and 

 ovaries, and other abdomino-pelvic procedures, even when apparently unattended by 

 infection. The predisposing causes are thought to be the relative immobility of the 

 patient and the consequent sluggishness of the circulation, especially in the lower 

 extremities, the dependent position of the limb in bed, and the altered constitution 

 of the blood (in the case of fever) ; the exciting cause is probably a very slight 

 degree of infection. Pain and oedema follow, but such cases almost always do well. 

 On account of its nearness to the artery, both vessels are often wounded at the same 

 time, with the resulting formation — if the communication between ihem is direct — 

 of an aneurismal varix ; or if it is indirect — an aneurismal sac intervening — of a 

 varicose aneurism. Wounds requiring ligation and sudden occlusion of the vein 

 from any cause are dangerous from the risk of development of moist gangrene. 

 Lateral suture of wounds in this vein has been successfully employed in a number of 

 instances. The femoral vein is not infrequently involved in ulcerative malignant 

 or phagedenic processes implicating the skin of the groin and upper thigh, or the 

 inguinal lymphatic nodes. 



After ligation, the collateral circulation is established between the veins of the 

 buttocks and the internal circumflex veins, and between the veins of the pelvis and 

 the external pudic veins. 



The practical relations of the femoral vein to femoral hernia have been described 

 (page 1773)- 



The popliteal vein, together with the artery (which is closer to the bone, and 

 therefore more easily compressed or torn), has been lacerated in supracondyloid 

 fracture of the femur. It has been so compressed by a popliteal aneurism as to cause 

 thrombosis and enormous distention of the veins and of the leg. Owing to the 

 unyielding character of the boundaries of the ham, it may also be sufificiently com- 

 pressed by inflammatory exudates, by abscess, or by enlarged bursae, to cause 

 swelling and oedema of the foot and leg. The vein is so exceptionally thick-walled 

 that in spite of its more superficial position it is never ruptured alone, but only when 

 the force is sufficient to tear the artery also. The involvement of both may be favored 

 by the fact that the two vessels are so closely united that it is difficult to separate them, 

 and this also favors the occasional production of aneurismal varix or varicose 

 aneurism after stab-wounds. This close connection makes the denudation of the 

 artery difficult in the operation for its ligation. 



The veins of the leg are, with the possible exception of the veins of the 

 pampiniform and hemorrhoidal plexuses, more often the subject of varicosity than 

 any other veins of the body. This is due to ( i ) the high blood-pressure in these 

 veins, resulting from {a) the erect posture of the human species and the consequent 



