The fascia lata is the broad fascial envelope of the proximal region of the lower limb, from the iliac crest, sacrum, and inguinal ligament proximally to the boney anatomy around the knee distally. It is thin posteriorly and medially and becomes thicker anteriorly. It reaches its greatest thickness on the lateral aspect where it is called the iliotibial tract. It is thick and reinforced around the knee as it associates with the tendons that attach in this region. It has two strong intermuscular septa that project from the fascia to compartmentalize the thigh muscles and attach to the linea aspera of the femur.