What anatomical structure is located at the distal end of the femur?

The anatomical structure located at the distal end of the femur is the patella, commonly known as the kneecap. The femur, which is the longest bone in the body, has a distinct articulation at its distal end that connects with the patella and the other two bones of the lower leg: the tibia and fibula.

The patella serves various important functions, including protecting the knee joint and improving the leverage of the quadriceps muscle, which enhances the efficiency of leg extension movements. It is situated anteriorly to the knee joint, essentially acting as a shield for the underlying joint structures.

Other structures mentioned, such as the acetabulum, are located in different areas of the anatomy. The acetabulum is part of the pelvis and serves as the socket for the hip joint; therefore, it is not located at the distal end of the femur. The tibia and fibula are both bones of the lower leg but connect with the femur at the knee joint rather than at the distal extremity of the femur itself. Thus, the patella is indeed the correct answer as it directly interacts with the distal end of the femur in the knee joint.