Chapter 4 The Skeletal System 157 bone at the site, resulting in repair of the injury. However, with repeated overuse, the remodeling process cannot keep up with the damage being done by the overuse. When this happens, the condition progresses to a stress fracture. Runners and athletes in sports such as soccer, basketball, gymnastics, and tennis are prone to stress fractures, particularly in the tibia and the metatarsals. Common causes are increasing running mileage or playing time too abruptly, running or repetitive landing on a hard surface, and wearing shoes with inadequate cushioning. Diagnosis of stress fractures is not always as straightforward as diagnosis of other types of fractures. The primary symptom is pain with activity. X-rays are the first tool for diagnosing a stress fracture. However, very small stress fractures may only be visible with a computed tomography (CT) scan or magnetic resonance imaging (MRI). The treatment for a stress fracture is rest. Resuming activity too soon can prevent healing. Epiphyseal Injuries Epiphyseal injuries include injuries to the epiphyseal plate, articular cartilage, and apophysis. An apophysis (a-PAHF-i-sis) is a site where a tendon attaches to a bone. Both acute and overuse- related injuries can damage the growth plate, potentially resulting in premature closure of the epiphyseal junction and termination of bone growth. Osteochondrosis (ahs-tee-oh-kahn-DROH-sis), also known as Osgood-Schlatter disease, is inflammation of the apophysis and growth plate at the superior end of the tibia. This apophysis is the site where the powerful quadriceps muscle group on the front of the thigh attaches to the tibia through a tendon extending down from the patella. The apophysis is positioned over the tibial growth plate. When the quadriceps is used a lot in running, jumping, and other sports activities during the adolescent growth spurt, the tibial growth plate and apophysis can become inflamed, swollen, and painful. Osteochondrosis is common in adolescents who play soccer, basketball, and volleyball, and who participate in gymnastics, with more boys affected than girls. The primary symptom is a painful region of swelling at the muscle attachment site, which can occur on one or both legs, as shown in Figure 4.35. The pain worsens with physical activity. tenderness around the fracture site. There may also be bruising, and in the case of a complete fracture, the limb may look deformed or out of place. A compound fracture, with a bone fragment protruding through the skin, is accompanied by bleeding and extreme pain. The most common treatment is application of a plaster or fiberglass cast to completely immobilize the fracture after the doctor has properly aligned the bone. Avulsions and incomplete fractures may be treated with a functional cast or brace, such as a walking boot. If the doctor cannot readily align the bone ends, traction may be applied to gently pull on opposite ends of the fractured bone to achieve proper realignment. With more serious, complicated fractures the doctor may elect to use external fixation. This is a surgical procedure in which metal pins or screws are placed into the broken bone above and below the fracture site. The pins or screws are connected to a metal bar outside the skin to hold the bones in the proper position while they heal. Figure 4.34 displays a variety of bone fractures. Stress fractures are tiny, painful cracks in bone that result from overuse. Under normal circumstances, bone responds to stress-related injury by remodeling. Osteoclasts resorb the damaged tissue, and osteoblasts deposit new Puwadol Jaturawutthichai/Shutterstock.com Figure 4.34 X-rays are an important diagnostic tool for finding bone fractures. Copyright Goodheart-Willcox Co., Inc.