1 A blood clot that forms inside one of your veins or arteries is called a thrombus. A thrombus may also form in your heart.  A thrombus that breaks loose and travels from one location in the body to another is called an embolus.
The kidneys. The kidneys do vital work in the body filtering blood removing waste into urine, and balancing electrolyte levels. Our blood in our bodies passes through the kidneys several times a day. The kidneys are located at the back of the abdomen. Each kidney is about the size of a fist - 10-12.5cm long.
The right kidney is located under the diaphragm and behind the liver. The left kidney is also located under the diaphragm but behind the spleen. Your kidneys are on your back sides just below your ribcage, yet above your waist.