IIIG Obstruction of the Large Venous Trunks. 



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

 difificult respiration occurred, like dyspnea or sudden asphyxia which 

 sometimes caused rapid death.— (Kappel, 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 comi3ression (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 

 especiallj' 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. Stenosis of the anterior vena. cava. Edematous infiltration of the region 

 of neck and shoulder; the 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 

 the 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 pulsation may become evident in the jugular veins. 



