Copyright Goodheart-Willcox Co., Inc. Chapter 5 The Skeletal System 159 osteopenia, which is characterized by reduced bone mass without the presence of a fracture. The osteopenia often progresses to osteoporosis, with fractures present. Although once regarded as primarily a health issue for women, the increasing age of the general population means that osteoporosis is now also becoming a concern for older men as well. Type 1 osteoporosis, also known as postmenopausal osteoporosis, affects about 50% of women after age 50. Type 2 osteoporosis, or age-associated osteoporosis, affects most women and also affects men over the age of 70. The radius and ulna, femoral neck, and spine are all common sites of osteoporotic fractures. Epiphyseal Injuries Epiphyseal injuries include injuries to the epiphyseal plate, articular cartilage, and the apophysis. An apophysis is a site at which 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, also known as Osgood-Schlatter disease, is another form of bone injury. The powerful quadriceps muscle group on the front of the thigh attaches distally to the upper tibia. When the quad- riceps is used a lot in sports activities during the adolescent growth spurt, the area of the tibia around the attachment site becomes irritated or swollen, causing pain. The condition is believed to be a result of overuse injuries that occur before the area has finished growing. Osteochondrosis is common in adolescents who play soccer, basketball, and volleyball, and in those who participate in gymnastics. Males are more often affected than females. The primary symptom is a painful region of swelling at the muscle attachment site, which can occur on one or both legs. The pain worsens with physical activity. SELF CHECK 1. List and describe the following types of fractures: simple, compound, comminuted, avulsion, spiral, greenstick, stress, impacted, crush, and wedge. 2. Explain osteochondrosis. 3. Why is it important for children to avoid activities that could cause damage to an epiphyseal plate? Osteoporosis Osteoporosis is a condition in which bone mineral- ization and strength are so abnormally low that regular daily activities can result in painful fractures. With its honeycomb structure, trabecular bone is the most common site of osteoporotic fractures (Figure 5.37). Age-Related Osteoporosis Osteoporosis occurs in most elderly individuals, with earlier onset in women. The condition begins as A B Dee Breger/Science Source [both images] Figure 5.37 Compare the normal trabecular bone (A) with the brittle, degraded bone (B) characteristic of osteoporosis. As the bone becomes more brittle, it is more likely to fracture.