The femur, commonly known as the thigh bone, is the longest and strongest bone within the human body. It extends from the hip down to the knee, serving as a foundational structure that supports the body’s weight and enables various movements. This bone facilitates activities such as standing, walking, and running, contributing to human mobility and stability.
The Femur’s Divisions
The femur is separated into three main sections: the proximal end, the shaft, and the distal end. The proximal end forms the ball part of the hip joint, connecting with the pelvis. The shaft is the long, cylindrical middle portion, providing structural support. The distal end, located near the knee, is the specific focus of this discussion. Each part contributes to the femur’s overall function.
Pinpointing the Distal Femur
The distal femur is the lower, wider extremity of the thigh bone, situated just above the knee joint. It expands in width as it approaches the knee. This section positions itself directly above the patella (kneecap) and the two lower leg bones: the tibia (shin bone) and fibula. Its location is key to the knee’s mechanics, forming the upper part of this complex joint. The distal femur is the widest part of the bone, designed to interact with both the shin bone and the kneecap.
Anatomical Landmarks
The distal femur features several distinct anatomical structures. The most prominent are the medial and lateral condyles, two rounded, smooth projections at the end of the bone. These condyles are separated by a deep groove on the posterior side called the intercondylar fossa or notch. Slightly above and to the sides of the condyles are smaller bumps known as the medial and lateral epicondyles, which serve as attachment points for ligaments that stabilize the knee. On the front surface of the distal femur, between the condyles, lies the patellar surface, a smooth, grooved area where the kneecap glides during knee movement.
Forming the Knee Joint
The distal femur plays a primary role in forming the knee joint, one of the body’s largest and most complex articulations. Its medial and lateral condyles articulate with the top surface of the tibia (tibial plateaus), creating the tibiofemoral joint. This connection is responsible for bearing the body’s weight and enabling the primary movements of the knee. The patellar surface on the front of the distal femur interacts with the posterior surface of the patella, forming the patellofemoral joint. These articulations allow for the knee’s range of motion, primarily flexion (bending) and extension (straightening) of the leg.