122 VETERINARY PATHOLOGY. 



THROMBOSIS. 



DEFINITION. 

 ETIOLOGY. 



Injured endotlicliiim. 



Mechanical — Artery forceps. 

 Atheromatous dei/eneralion. 

 Insufficient nutrition. 

 Foreign bodies — Parasites, etc. 

 Retarded rate of blood Hozv. 

 Increased coagulability of blood. 

 PROCES.S OF FORMATION. 

 LOCATION. 



Occurs in all vessels, more prevalent in veins and heart. 

 VARIETIES OF THROMBI. 

 Color. 

 Red. 

 White. 

 Mi.red. 

 E.rtent. 

 Partial. 



Lateral. 



Parietal {annular'). 

 Complete (obstructive). 

 EXTEN.SION OF THROMBI. 

 APPEARANCE. 



SECONDARY CHANGES OF THROMBI. 

 Decolorization. 

 Softening. 

 Simple. 

 Infective. 

 Organization. 

 Calcification. 

 EFFECTS DEPEND UPON. 

 I'essels obstructed. 

 Secondary changes of thrombi. 



Thrombosis is the condition resulting from a coagulation 

 of blood within the vessels or heart during life. A thrombus 

 is the coagulated blood within a living vessel. The accumula- 

 tion and adhesion of leucocytes on the interior of vascular 

 channels is also spoken of as a thrombus. The term thrombus 

 should not be confused with a coagulum or a clot. A coagulum 

 is coagulated blood within a vessel formed after death of the 

 vessel wall, and a clot is coagulated blood formed outside of 

 the vessel. 



Tl.rombosis is of quite common occurrence. It is occa- 

 sionally a sequel of parturition. Thrombic formation of one 

 or both of the iliac arteries of the horse is a demonstrated 

 cause of lameness. Thrombo-embolic colic of the horse is 

 caused by thrombosis of the anterior mesenteric artery. The 

 appearance of ante-mortem clot is familiar to all post-mortem 

 examination observers. Intravenous or intra-arterial injections 

 are probably always succeeded bv thrombic formation at the 



