Often referred to as the thigh muscle, the quadriceps femoris runs along the length of the femur bone in the upper leg. It is vulnerable to a variety of injuries, especially those caused by compression forces. These injuries may range in severity from simple strains to serious muscle ruptures. The most common quadriceps injury is contusion, which is usually caused by a direct blow to the thigh, either by an object or another person. In rare cases, this injury can develop into acute compartment syndrome. Other common quadriceps injuries include strains of the quadriceps tendon, complete and partial tears of the quadriceps tendon, and rupture of the muscle or tendon. Strains are common and often are associated with participation in certain sports, including rugby, karate, and football. The incidence of rupture is higher in older patients and young athletes, especially those participating in high jumping, basketball, and weightlifting. In addition to rest, icing, and compression, treatment of most quadriceps injuries will include a physical therapy program to promote strength and flexibility in the region. In some cases—especially those involving compartment syndrome, hematomas, bony avulsion, and complete tendon rupture—surgery may be necessary. Note that torn ligaments and tendons typically require the same amount of healing time as do fractured bones. For mild strains, healing may take two to ten days; for moderate strains, ten days to six weeks; and for severe strains, six to ten weeks.