femuren

The femur, or thigh bone, is the longest and strongest bone in the human skeleton, extending from the hip to the knee. It typically measures about 45 cm in length in an average adult and can withstand substantial loads, acting as a primary weight-bearing lever. In Swedish, the bone is called femuren.

The proximal end includes the femoral head, which articulates with the acetabulum to form the hip joint, a neck, and the greater and lesser trochanters for muscle attachment. The shaft is cylindrical and thick-walled, with the linea aspera a prominent ridge on the posterior surface for muscle attachments. The distal end bears the medial and lateral condyles that articulate with the tibia and form part of the knee joint, and the anterior surface features the patellar groove (trochlear groove) for patellar articulation.

Blood supply comes mainly from the profunda femoris and its perforating branches, plus the medial and lateral circumflex femoral arteries. The retinacular arteries supply the femoral head, making intracapsular fractures a particular risk for avascular necrosis. Nerve supply to the bone and periosteum derives from nearby nerves, notably branches of the femoral nerve for the anterior aspects, with the obturator and sciatic nerves contributing to surrounding structures.

Development and function: The femur forms by endochondral ossification, with growth at the proximal and distal physes; the distal growth plate closes in late adolescence. Functionally, the bone transfers weight from the pelvis to the knee and serves as a lever for large, powerful leg muscles.

Clinical notes: Fractures commonly occur after high-energy trauma or in osteoporosis. Common sites include the femoral neck, intertrochanteric region, and subtrochanteric area. Treatment often involves surgical fixation with intramedullary nails or plates and screws, followed by rehabilitation. Potential complications include avascular necrosis of the femoral head and nonunion.