Thrombus is defined as what?

• A. Bruising of tissue
• B. Systemic infection
• C. Inflammation of vein
• D. Blood clot due to insufficient pressure after needle

Answer: (D)

A thrombus is a blood clot that forms inside a blood vessel or the heart when the coagulation system activates and platelets and fibrin come together to seal a site of injury. It can stay attached to the vessel wall or grow and block blood flow, leading to problems like deep vein thrombosis or arterial occlusion. This is different from a bruise (hematoma), which is blood that pools outside vessels, a systemic infection, or inflammation of a vein. The idea of a clot forming after a needle because of insufficient pressure isn’t what defines a thrombus; inadequate pressure after venipuncture is more likely to cause a hematoma or continued bleeding, whereas a thrombus refers to clot formation within the circulation itself.