What is lower leg and upper leg?
upper leg- thigh
lower leg- calf
There is no scientific name other than "thigh", which is in such common usage that it just doesn't sound very scientific, but it is. Note that the lower leg's scientific name is "crus". In anatomical terminology the "leg" is only that part of the body between the knee and the ankle and what we commonly called the leg is "the lower extremity".