The femur (Gray's Anatomy: anterior surface, posterior surface) is a long bone that runs from and forms part of the hip joint and extends distally to the knee joint. It is the longest bone in the body.
Proximally (Gray's Anatomy) is the femoral head, which articulates with the acetabulum of the pelvis. The femoral head forms approximately two thirds of a sphere. The fovea is a pit located slightly posteriorly to the center of the head. The head is completely covered with articular cartilage with the exception of the fovea. The ligamentum teres (or ligament to the head of the femur) runs from the transverse acetabular ligament to the fovea.
The femoral neck connects the femoral head to the shaft of the femur. The shaft of the femur has a medial inclination as it extends distally.
The shaft has a slight anterior convexity (Neumann, 2002). The intertrochanteric line is located more anteriorly, serving as attachment for the capsular ligaments. The greater trochanter projects laterally and posteriorly from the meeting of the femoral neck and shaft and serves as attachment for many muscles surrounding the hip. The trochanteric fossa is a small pit on the medial side of the greater trochanter and serves as an attachment site of the obturator externus.
