Is the superior end of the thigh bone joins with the knee cap?

No, the superior end of the thigh bone (femur) does not directly join with the knee cap (patella). Instead, the femur articulates with the tibia and fibula at the knee joint. The patella is located in front of the knee joint, serving as a protective bone that improves the leverage of the quadriceps muscle. It connects to the femur via the patellar tendon but does not form a direct joint with it.