DISEASES OF THE GREAT VENOUS TRUNKS. 429 



On the other hand, it is tolerably common even when the aorta is 

 sound in cases of deficience of the mitral valve, with consecutive hyper- 

 trophy of the right ventricle. To it Dittrich attributes the frequence 

 of hsemorrhagic infarction in tne lungs of persons with heart-disease. 



Aneurisms of the pulmonary artery are exceedingly rare, and never 

 attain any considerable size. In a case observed by Skoda there was 

 found in this artery an aneurism as large as a goose-egg. During life 

 the patient had labored under signs of grave circulatory disturbance, 

 was cyanotic and dropsical; but no diagnosis could be formed by 

 physical exploration. 



Diffuse dilatation of the pulmonary artery occurs with extraordi- 

 nary frequence in cases which cause hypertrophy and dilatation of the 

 right heart. It never produces any change in the percussion-sound 

 over the chest (Skoda\ but not unfrequently, and usually upon dias- 

 tole, we perceive a shock, and, indeed, a distinct pulsation, in the 

 vicinity of the root of the pulmonary artery. 



While treating of metastases of the lung, we have already learned 

 that the minuter branches of the pulmonary artery may become ob- 

 structed by the intrusion into them of wandering emboli. When one 

 of the larger branches is thus occluded, intense dyspnoea arises, and 

 even death may suddenly ensue from the extent of breathing-surface 

 thus thrown out of action from interruption of its circulation. Within 

 the last few years I have seen two cases in which death occurred in the 

 course of a few hours, with all the signs of extreme dyspnoea and col- 

 lapse, and in which it was found post mortem that a large thrombus 

 had been detached from the femoral vein, had passed into the circula- 

 tion, and, by obstruction of the main branch of the pulmonary artery, 

 had occasioned this peculiar kind of suffocation. One of these cases 

 is reported in the WUrtemberger Correspondenzblatt by my then as- 

 sistant, Dr. Spath. 



CHAPTER VI. 



DISEASES OF THE GREAT VENOUS TRUJtfKS. 



IT is of disorders affecting the vena cava and the pulmonary veins 

 alone that we now treat, as diseases of the peripheral veins are 

 treated of in the hand-books of surgery ; those of the portal vein and 

 veins of other organs are more appropriately discussed as diseases of 

 the liver, etc. 



Primary inflammation does not occur in the vena cava, and it is 

 rare to observe inflammation and perforation of the coats of the as- 

 cending portion of it by an abscess of the liver, or of the cellular tissue 



