Chapter 1: The Musculoskeletal System

CHAPTER OBJECTIVES

At the completion of this chapter, the reader will be able to:

1. Describe the various types of biological tissue of the musculoskeletal system.

2. Describe the tissue mechanics and structural differences and similarities between the muscle, tendons, fascia, and ligaments.

3. Describe the different types of joints and their various characteristics.

4. Define the various terminologies used to describe the joint position, movements, and relationships.

5. Give definitions for commonly used biomechanical terms.

6. Describe the different planes of the body.

7. Define the body’s center of gravity and its location.

8. Describe the different axes of the body and the motions that occur around them.

9. Define the terms osteokinematic motion and arthrokinematic motion.

10. Differentiate between the different types of motion that can occur at the joint surfaces.

11. Describe the basic biomechanics of joint motion in terms of their concave–convex relationships.

12. List the different types of levers found within the body and provide examples of each.

13. Describe the difference between a closed and open kinematic chain and how each can influence an exercise prescription.

14. Define the terms close-packed and open-packed and the significance of each.

OVERVIEW

The correct embryonic development of the musculoskeletal system requires a coordinated morphogenesis of the body’s fundamental tissues. Throughout the human body, there are four major types of tissues:

• Epithelial. Epithelial tissue covers all internal and external body surfaces and includes structures such as the skin and the inner lining of the blood vessels.

• Connective. Connective tissue (CT) includes four classes: CT proper, bone, cartilage, and blood tissue. In the embryo, muscle tissue and its fascia form as a differentiation of the paraxial mesoderm that divides into somites on either side of the neural tube and notochord. The cartilage and bone of the vertebral column and ribs develop from the anterior (ventral) part of the somite, the sclerotome. The dermomyotome, which is the posterior (dorsal) part of the somite, gives rise to the overlying dermis of the back and the body’s skeletal muscles and limbs. CT provides structural and metabolic support for other tissues and organs of the body.

• Muscle. Muscles are classified functionally as voluntary or involuntary, and structurally as smooth, striated (skeletal), or cardiac. There are approximately 430 skeletal muscles in the body, each of which can be considered anatomically as a separate organ. Of these 430 muscles, about 75 pairs provide the majority of body movements and postures.

• Nervous. Nervous tissue provides a two-way communication system between the central nervous system (brain and spinal cord) and muscles, sensory organs, and various systems (see Chapter 3).