This chapter is designed to present information on the musculoskeletal system in childhood and adolescence and to relate this information to pediatric disorders commonly seen by the physical therapist. The chapter is divided into three main sections. The first section contains information on developmental biomechanics, including principles of growth and musculoskeletal development during childhood and adolescence. The second section reviews the histology and anatomy of the main musculoskeletal tissue systems—connective tissue, bone, and muscle—relating each to specific pediatric disorders. The third section discusses the comprehensive pediatric musculoskeletal examination process, including specific procedures and their evaluation.
Developmental biomechanics is defined as “the effects of forces on the musculoskeletal system during the entire life span” (LeVeau & Bernhardt, 1984, p. 1874). Understanding how the musculoskeletal system changes and reacts to internal and external forces provides a framework to evaluate musculoskeletal examination data and develop a plan of care. This section highlights the major principles of musculoskeletal growth and discusses the changes that occur from birth and throughout childhood.
Principles of Growth and Development
In this section, the basic structure and function of three key tissues in the musculoskeletal system—connective tissue, bone, and muscle—are discussed as they affect child development and function. During development and, to a lesser extent, throughout life, biological tissue is created, shaped, and remodeled through external or internal forces. Tissues respond not only to the different types of forces to which they are exposed in the intrauterine and extrauterine environments, but also to the direction and amount of force. In addition to force, which is only one factor that influences body size, shape, genetics, nutrition, drugs, and hormones also influence body structure. An appreciation of the typical sequence of development and the impact of pathological influences on these tissues will assist the physical therapist in identifying deviations from typical development and may allow prevention or remediation of impairments and limit disability. Principles of growth and development will also be applied to the key musculoskeletal tissue systems.
Musculoskeletal Tissue Systems
There are two general types of connective tissue—dense ordinary connective tissue and cartilage. Dense ordinary connective tissue can have a regular or irregular arrangement. Tendons and ligaments have regular arrangements of dense ordinary connective tissue, which is best suited to withstand tension only in the direction of the fibers. This arrangement makes them strong to resist the pull of muscles. The connective tissue that surrounds the bones, muscles, heart, and other areas is irregularly aligned and withstands tension in a number of directions.
Tendons are composed of tightly packed bundles of parallel collagen fibers. If the tendon rubs over a bone or other friction-producing surface, synovia (synovial fluid) acts as a lubricant. The synovial sheath is made up of an inner sheath that ...