CONTUSIONS 47 



CONTUSIONS. 



Define a contusion. 



An injury due to pressure by a blunt body, rending 

 asunder subcutaneous tissue elements, but witliout a visible 

 skin wound. 



Differentiate between a contused wound and a contusion. 



In a contused wound there is a primary visible infected 

 cutaneous wound. In a contusion there is no primary visible 

 infected wound. The distinction between them is one ' of 

 degree and not of kind. 



Name causes of contusions ? 



In the horse, saddle and harness pressure about the back, 

 breast and head ; in the hoof by shoes and crowding nails; 

 blows, falls, etc. In cattle, blows from horns ; and in the 

 dog, bites, blows. 



According to the extent and severity of the subcutaneous 

 lesions, what degrees of contusion are recognized ? 



1. Contusion of the first degree. Limited hemorrhage, 

 the bruised tissues are uniformly infiltrated by the extrava- 

 sation (hemorrhagic infiltration), or the extravasation ac- 

 cumulates in small circumscribed patches (ecchymosis, sug- 

 gilation). 



2. Contusion of the second degree. The effused blood 

 collects in a subcutaneous cavity and forms a blood tumor 

 (hematoma). When the blood effusion spreads over a 

 diffused area it is termed a suffusion. 



3. Contusion of the third degree. The bruised parts 

 undergo necrosis, not as the direct result of the bruising, but 

 due to (1) circulatory disturbances caused by the injury to 

 the blood vessels, this process being termed primary anemic 



