5 Copyright Goodheart-Willcox Co., Inc. 120 The Skeletal System Chapter 5 Outline Section 5.1 Bone • Functions of the Skeletal System • Bone Classification and Structure Section 5.2 Development of Bones • Bone Growth and Development • Bone Remodeling Section 5.3 The Axial Skeleton • Skull • Vertebral Column • Thoracic Cage Section 5.4 The Appendicular Skeleton • Upper Extremity • Lower Extremity Section 5.5 Joints • Types of Joints • Articular Tissues Section 5.6 Injuries and Disorders of the Skeletal System • Common Bone Injuries • Osteoporosis • Common Joint Injuries • Arthritis P eople tend to think of bone as a hard, dried-up chunk of mineral that a dog would enjoy chewing. While this is true of dead bone, the living bones inside the human body are made up of amazing, complex living tissues. Bones are not only hydrated (containing water), but also very dynamic, continually changing in size, shape, and strength over time. How and why do these processes and changes occur? This chapter explores the characteristics of living bone and describes the well-tailored functionality of the major bones and joints in the human skeleton. It also discusses some of the common injuries and disorders of the bones and joints, how these problems tend to occur, and in some cases, how their likelihood can be reduced. Clinical Case Study Fifteen-year-old Dan is a healthy adolescent who eats a balanced diet and gets plenty of sleep. He is also the star player on both his high- school JV soccer team and his travel soccer team. His team plays for 10 months per year, and while the seasons overlap between the two teams, he attends soccer practices at least five days per week and typically has two games per week. For about the last six months, Dan has been experiencing pain and swelling around the anterior aspect of his right knee that worsens with activity and has prevented him from finishing many of his games. He does not recall having had an injury to the knee, and other than the pain and swelling, he has no observable symptoms. Dan’s travel coach frankly wonders if Dan might be faking his pain for some reason, since his play is not affected during the first half of his soccer matches. But the pain is real, and Dan finally sees a physician. The physician questions Dan about his activities, the nature of the pain he is experiencing, and the length of time that this has been a problem. She also orders an X-ray of the leg to rule out a fracture. When the results of the X-ray come back negative, she is able to make a diagnosis based on the symptoms and case history. Among the conditions and injuries discussed in the chapter, which ones might Dan have, and which do you think is most likely? sutisakphoto14/Shutterstock.com