The femur is a free lower extremity bone and is the longest long tubular bone in the human body. The femur is located in the femoral region of the body, which is bounded in the upper part of the body by the groin and abdomen, and in the lower part by the two transverse fingers above the patella. The length of the femur is about 1/4 of the height of the body. it is divided into two ends of the body, with the femoral head at the upper end, the neck as the narrow, thin part of the head below the outer side, and the greater trochanter of the femur visible as a square bulge above the outer part of the neck where it meets the body and palpable about 10 cm below the anterosuperior iliac spine. There is an inward angle between the neck of the femur and the long axis of the body, which is called the cervical stem angle, and the normal adult angle ranges from 125° to 130°, with an average of 127°. When the angle is greater than 130°, it is hip exostosis; and when it is less than 125°, it is hip endostosis.