The femur (thighbone) is the longest and strongest bone in the body. Although strong, it can still be broken, most typically for the general population in motor vehicle accidents. It is categorized as a long bone because it is longer than it is wide, bears weight, and supports movement. The major features of the femur include the femoral head and neck, greater and lesser trochanters, femoral shaft, and the medial and lateral condyles.
Biomechanically, the femur supports the weight of the body during activities such as walking, running, and jumping. Forces during high-impact activities can easily exceed 3 times body weight. The femur is a major component of the kinematic chain of the leg, along with the shank and the foot.
The femur is part of two major body joints, the hip and the knee. The head of the femur lies at the proximal (nearer to the center of the body) end and articulates with the concave acetabulum (hip socket) of the pelvis to form the ball-and-socket hip joint. The distal (farther from the center of the body) end of the femur contains the femoral condyles that articulate with the plateau of the proximal tibia to form the knee joint. These joint surfaces are covered in hyaline cartilage, which is referred to as “articular” cartilage when it is on the bones at joints, because it assists articulation. It provides some cushioning and a smooth, low-friction surface. Several ligaments support the hip and knee joints, allowing movement while keeping the bones together.
