A thrombus is a blood clot that is located within a blood vessel in the body or within the heart. The development of a thrombus is referred to as thrombosis. There are a variety of factors that can cause thrombosis, including injury, dehydration, and certain genetic conditions.
A thrombus usually develops when platelets deposit on plaques within blood vessels formed by atherosclerosis. A thrombus refers to a blood clot that stays in one place in the body. It can limit or completely obstruct blood flow, causing affected organs and tissues to be deprived of nutrients.

