136 



\i;ri:KiNARV ?athology. 



lernal pressure. If the external pressure is materially dimin- 

 islied, tliere will be arterial liyperemia of the cutaneous arteries 

 as is evidenced in liyperemia produced by cupping;. Collateral 

 ischemia mav cause I'lypcremia of the related parts for tlie same 

 reason tliat cdllateral hyperemia may cause ischemia. 



Appearance.— .l/(7(T()i-c«/';c.— An arterial hyperemic part is 

 scarlet red in cobir, usually feels dense, dry and has an increased 

 temperature. If the tissues are incised, blood escapes freely. 





"'Jii" 





• " • • ■ -a; •'X* ♦ * ■"- 







^-"L'JLJJS- 



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Fig. ST. — H.^ pert" inia i.iT Jvidnry, sh(j\viiig- Lngor^.d (.aplllarifS. 



Microscopic. — Ti:^sues affected with arterial liv])ereniia con- 

 tain dilated arteries and cap.illaries, the lymph spaces are en- 

 S'orged with lym]ih, the tissue cells iiia\' be considerably swollen 

 and diapcdesis ma\- be noted. 



Effects. — The eitects uf arterial hyperemia de])eiid upon 

 tlie cause, degree, and duration and organs affected. Arterial 

 hyperemia caused h)' infective agencies is more serious than 

 if caused by other means. Arterial liy])creniia of a stlienic 

 type is usually succeeded by inflammation and asthenic hyper- 

 emia iiia\' terminate in recovery. 



