The femur, also known as the thigh bone, is the longest, strongest, and heaviest bone in the human body. It is the only bone in the upper portion of the leg and runs from the hip to the knee. The femur has several important jobs, including weight-bearing, gait stability, and supporting important muscles, tendons, ligaments, and parts of the circulatory system. The femur is critical in helping you maintain stability so you don’t fall over easily. The femur is made up of several parts, including the head, neck, shaft, greater and lesser trochanters, intertrochanteric line, trochanteric crest, and medial and lateral condyles. The head of the femur articulates with the acetabulum of the pelvis to form the hip joint, while the bottom of the femur connects to the shinbone (tibia) and kneecap (patella) to form the knee. The femur is covered all around by thigh muscles. The femur is constantly changing, and you build strong and healthy bones in your childhood and adolescent years so that.