TYPHOID FEVER 41 



is more common in the lower limbs and in the left femoral vein or 

 its popliteal and saphenous tributaries than elsewhere. This 

 proclivity of the left side is partly explained by the fact that the 

 left common iliac vein, which receives the blood from the left 

 lower extremity, is crossed near its termination by the right 

 common iliac artery, and thus the circulation may be impeded. 

 Clot extending along one common iliac vein may ultimately block 

 the veins of both lower limbs. 



When arterial thrombosis occurs it is usually in the femoral or 

 popliteal arteries, both of which may be considered liable to slight 

 injury where they cross the joint flexures. From obstruction 

 in smaller vessels peripheral gangrene may occur. Parts liable 

 from their anatomical situation to suffer in this way are the feet, 

 ears, nose, penis, labia, corneae, etc. 



Clots detached from the veins may be carried through the right 

 heart and produce pulmonary embolism, and the same accident 

 may occur when a thrombus in the right heart is detached by 

 some undue exertion and becomes impacted in the pulmonary 

 artery in a coiled-up form. 



Diffuse arteriosclerosis may show itself in later life as the 

 result of the vascular infection which occurs in typhoid fever. 



The lenticular .rose spots are of vascular origin. They probably 

 depend upon capillary infections and paralysis. The bacilli can 

 be obtained from the spots and the eruption is not seen after 

 death. 



Typhoid osteitis and periostitis is said to occur by preference 

 in the regions of the epiphyses in young people in whom these 

 parts have an extraordinarily free blood supply. In adults, the 

 tibiae, femora, sternum and ribs are most frequently attacked 

 because the tibiae in particular are exposed to injury, and the 

 sternum and ribs are very vascular. The spine is sometimes 

 invaded. 



Laryngeal ulceration in typhoid fever is found in those parts 

 of the larynx which are said to be freely supplied with lymphoid 

 tissue. The ulcers are apt to occur at the base of the epiglottis, 

 on the posterior wall of the larynx, on the false cords, between 



