The femur, commonly known as the thigh bone, is the longest and strongest bone in the human body. It supports the body’s structure and facilitates movement. Like all long bones, the femur is divided into distinct sections, each with specialized characteristics. This article focuses on the lower, or distal, portion of the femur, covering its location, functions, and common problems.
Where is the Distal Femur?
The distal femur is the lower, widened end of the thigh bone, positioned just above the knee joint. It forms the upper part of the knee, connecting with the shin bone (tibia) and kneecap (patella). Its flared shape provides a broad surface for articulation.
Key anatomical landmarks in this region include the medial and lateral condyles, two rounded eminences that form the primary articulating surfaces with the tibia. Between these condyles is a deep notch, the intercondylar fossa, which serves as an attachment site for knee ligaments. The patellar surface, a smooth, shallow depression on the front of the distal femur, articulates with the kneecap.
What Does the Distal Femur Do?
The distal femur primarily supports body weight and enables knee movement. It bears a significant portion of the body’s weight, transferring forces from the torso through the leg to the ground during activities like standing, walking, and running. This weight-bearing capacity is essential for upright posture and stability.
The smooth articular surfaces of the distal femur, covered by articular cartilage, allow efficient, low-friction movement within the knee. This enables knee movements like flexion (bending) and extension (straightening). The distal femur also provides attachment points for various muscles and ligaments that contribute to knee strength and stability.
Common Problems with the Distal Femur
The distal femur can be affected by various injuries and conditions, given its role in weight-bearing and movement. Fractures in this region are common, often resulting from high-impact trauma like falls or motor vehicle collisions. These fractures can range from simple cracks to complex breaks, sometimes extending into the knee joint itself.
Specific types of fractures include supracondylar fractures, occurring just above the condyles, and intercondylar fractures, involving the area between the condyles. Osteoarthritis, a degenerative joint disease, is another common issue affecting the articular cartilage covering the distal femur. This condition leads to pain, stiffness, and reduced mobility as the cartilage wears away. Other issues include osteochondritis dissecans, where cartilage and underlying bone separate, and ligament injuries that can compromise knee stability.