What term describes a clot that is attached to a vessel wall?

The correct term for a clot that is attached to a vessel wall is "thrombus." A thrombus forms when blood components aggregate and clot at a specific site within a blood vessel, which can occur in both veins and arteries. This process can happen in response to various factors, including injury to the vessel wall, slow blood flow, or an imbalance of clotting components in the blood.

The distinction between a thrombus and an embolus is important. An embolus refers to a clot or other material that can travel through the bloodstream to another location, whereas a thrombus is stationary, remaining attached to the vessel where it formed. Understanding this terminology is crucial in fields related to circulatory health and pathology, as the implications for treatment and prognosis can differ greatly depending on whether a clot is a thrombus or an embolus.

The remaining options refer to different medical conditions not related to the attached clot concept. Shock is a life-threatening condition from inadequate blood flow and oxygenation to tissues, while lymphedema is the buildup of fluid in tissues, often due to lymphatic system obstruction.