1116 



Obstruction of the Lar^e Venous Trunks. 



(Ktippel found this to have been the case in 12 out of 38 instances), 

 difficult resijiration occurred, like dyspnea or sudden asphyxia which 

 sometimes caused rapid death. — (Kiippel, Z. f. Tm., 1904. VIII. 321. — 

 Prevot, Bull., 1908, 625.). 



4. Obstruction of the Large Venous Trunks. Thrombosis 



Venarum. 



Obstruction of the large venous trunks is rare and is usually 

 due to compression (by enlarged lymph glands, tumors, 

 abscesses), less often it occurs in connection with endophlebitis 

 or slowing of the circulation. 



Cases of thrombosis of the venae cavae have been observed 

 especially in horses and cattle, once also in a dog. In the horse 

 thrombosis of the portal vein has been known to occur. 



l''ig. 198. t^tciiosis of the anterior vena cava. Edematous infiltration of the region 

 of neck and shoulder ; tlic swelling is sharply arrested near the xiphoid cartilage. 



The symptoms are easily interpreted by the anatomical 

 arrangement of the venous trunks, because stenosis or obstruc- 

 tion of one vena cava produces venous stasis in that part of 

 tlie body from which the vein returns the blood to the heart. 

 Thus thrombosis of the anterior vena cava produces strong- 

 filling of the veins of head, neck, anterior extremities, and 

 thorax, also edematous infiltration of these regions or dropsy 

 of the chest (Fig. 198). If the obstruction is incomplete a neg- 

 ative 2)ulsation may become evident in the jugular veins. 



