Precava is a medical term used to describe the superior vena cava, the large vein in the body that carries de-oxygenated blood from the upper body back to the heart. This term is commonly used in medical textbooks and literature. Some synonyms for precava include the superior vena cava, upper vena cava, and cranial vena cava. Other terms that may be used to refer to this vein include the venae cavae, which encompasses both the superior and inferior vena cava, and the right atrial appendage, which is the chamber of the heart that receives blood from the superior vena cava.