The document discusses thrombosis and embolism. It defines thrombosis as the formation of a blood clot within a blood vessel and embolism as a detached blood clot that travels through the bloodstream. It covers topics like the mechanisms of hemostasis (clot formation), factors that predispose to thrombosis, morphology of arterial and venous thrombi, types of thrombosis like deep vein thrombosis and their clinical presentations.