Atheroma and thrombi.... I have read that atheromas usually result when a tear occurs in the endothelium occurs which allows phagocytes and LDL's to enter, etc. Why does this occur rather than a thrombus form first? Afterall, clots form when we cut ourselves as a result of the blood being exposed to collegen - surely this would be exposed when a tear occurs in the endothelium? Also, I have read that atheromas, as they are rigid, can break and this leads to formation of thrombi - is this because collegen in vessal walls is exposed, or something inside the atheroma? Thanks in advance.