Specifically, trace the path of a clot from the leg leading to the lung
A clot that forms in the leg then breaks loose and travels to the lung (pulmonary embolism) would likely take the following route: Saphenous vein in the lower leg possibly to the popliteal vein to the femoral vein in the thigh/groin. The femoral vein joins the inferior vena cava in the abdomen which empties into the right atrium of the heart. The right atrium pumps the blood (with the clot in it) into the right ventricle which in turn pumps the blood out to the pulmonary vasculature via the pulmonary arteries.
I don't know what you want, by the time I tell you, it's already there.
Step 1: open textbook
Step 2: read associated material
Step 3: formulate answer
See...homework isn't so hard!
The embolus will pass up through the leg, via the femoral vein. It will continue into the iliac vein, and then into the inferior vena cava. It will enter the heart at the right atrium, pass into the right ventricle, and into a pulmonary artery. The pulmonary artery will branch multiple times, becoming smaller with each bifurcation, eventually becoming small enough that the clot cannot pass through.
Up the femoral vein, into the inferior vena cava, then to the right atrium of the heart, then to the right ventricle, then to the pulonary artery
Blood goes all around the body. Lets say you start tracking it in the heart. It goes to the lungs to pick up oxygen. Then back to the heart (the pump) to get pushed out to the body. It will give up its oxygen along the way and needs to return to the heart for another boots, sending it to the lungs again.
So you have a clot in the leg and it breaks away from the wall of the vein. It will travel along the blood stream like a little boat in a river until it gets to a vein so small it cant go any farther. When it clogs the vein or artery, you have a pulmonary embolism.