Student Objectives When you have completed the exercises in this chapter, you will have accomplished the following objectives: Classification of Joints 1. Define joint or articulation. 2. Classify joints structurally and functionally. Fibrous Joints 3. Describe the general structure of fibrous joints. Name and give an example of each of the three common types of fibrous joints. Cartilaginous Joints 4. Describe the general structure of cartilaginous joints. Name and give an example of each of the two common types of cartilaginous joints. Synovial Joints 5. Describe the structural characteristics of synovial joints. 6. Compare the structures and functions of bursae and tendon sheaths. 7. List three natural factors that stabilize synovial joints. 8. Name and describe (or perform) the common body movements. 9. Name and provide examples of the six types of synovial joints based on the type of movementis) allowed. 10. Describe the elbow, knee, hip, jaw, and shoulder joints in terms of articulating bones, anatomical characteristics of the joint, movements allowed, and joint stability. Homeostatic Imbalances of Joints 11. Name the most common joint injuries and discuss the symptoms and problems associated with each. 12. Compare and contrast the common types of arthritis. 13. Describe the cause and consequences of Lyme disease. Developmental Aspects of Joints 14. Discuss factors that promote or disturb joint homeostasis. 172
Chapter 8 Joints 173 Joints are structures that connect adjoining bones. Except for the hyoid bone, and sesamoid bones like the patella, each bone contacts at least one other bone at a joint. A typical joint includes the adjacent surfaces of the bones and the fibrous tissue or ligaments that bind the bones together. In addition to binding the bones together, joints provide the skeleton with the flexibility to permit body movements. Because joints vary in structure and range of motion, it is convenient to classify them on the basis of their structure (fibrous, cartilaginous, or synovial) and function (the degree of joint movement allowed). Topics for review in Chapter 8 include the classification of joints, the structures of selected synovial joints, joint impairment, and changes in the joints throughout life. BUILDING THE FRAMEWORK Classification of Joints 1. Write your answers to the following questions in the answer blanks. 1. What are the two major functions of joints? 2. List three criteria used to classify joints. 3. For each of the structural joint categories-fibrous, cartilaginous, and synovial-give the most common functional classification and describe the degree of movement.
174 Study Guide for Human Anatomy & Physiology Fibrous, Cartilaginous, and Synovial Joints 1. For each joint described below; select an answer from Key A. Then, if the Key A selection is other than C (synovial joint), classify the joint further by making a choice from Key B. KEY A: A. Cartilaginous KEY B: 1. Gomphosis 4. Syndesmosis B. Fibrous 2. Suture 5. Synchondrosis C. Synovial 3. Symphysis 6. Synostosis 1. Characterized by hyaline 10. Costosternal joints 2-7 cartilage connecting the bony portions 11. Joint providing the most protection to underlying 2. All have a fibrous capsule structures lined with a synovial membrane surrounding a 12. Often contains a fluid-filled joint cavity cushion 3. Bone regions united by 13. Child's epiphyseal plate made fibrous connective tissue of hyaline cartilage 4. Joints between skull bones 14. Most joints of the limbs 5. Joint between atlas and axis 15. Teeth in body alveolar sockets 6. Hip, elbow; knee, and intercarpal joints 7. Intervertebral joints (between vertebral bodies) 16. Joint between first rib and manubrium of sternum 17. Ossified sutures 8. Pubic symphysis 18. Distal tibiofibular joint 9. All are reinforced by ligaments 2. Which structural joint type is not commonly found in the axial skeleton and why not? -----------------------------
Chapter 8 Joints 175 3. Figure 8.1 shows the structure of a typical synovial joint. Select different colors to identify and color the following areas. Then label the following: the more proximal epiphyseal line, the more distal epiphyseal line, spongy bone, periosteum. o Articular cartilage of bone ends o Fibrous capsule o Synovial membrane o Joint cavity Figure 8.1 4. Match the key choices with the descriptive phrases below, to properly characterize selected aspects of synovial joints. Key Choices A. Articular cartilage C. Ligaments and fibrous capsule B. Synovial fluid D. Muscle tendons 1. Keeps bone ends from crushing when compressed; resilient 2. Resists tension placed on joints 3. Lubricant that minimizes friction and abrasion of joint surfaces 4. Keeps joints from overheating 5. Helps prevent dislocation
176 Study Guide for Human Anatomy & Physiology 5. Match the body movement terms in Column B with the appropriate description in Column A. (More than one choice may apply.) Column A Column B I. Movement along the sagittal plane that A. Abduction decreases the angle between two bones B. Adduction 2. Movement along the frontal plane, away from the body midline; raising the C. Circumduction arm laterally D. Depression 3. Circular movement around the longitudinal bone axis; shaking the head "no" E. Dorsiflexion 4. Slight displacement or slipping of F. Elevation bones, as might occur between the carpals of the wrist G. Eversion 5. Describing a cone-shaped pathway with H. Extension the arm I. Flexion 6. Lifting or raising a body part; shrugging the shoulders J. Gliding t, " ~.. 7. Moving the hand into a palm-up (or K. Inversion forward) position L. Plantar flexion 8. Movement of the superior aspect of the foot toward the leg; standing on M. Pronation the heels N. Protraction 9. Turning the sole of the foot medially O. Retraction 10. Movement of a body part anteriorly; jutting the lower jaw forward p. Rotation II. Common angular movements Q. Supination 6. Figure 8.2 illustrates types of movements allowed by synovial joints. Match the letters on the figure with the types of movements listed below. Insert your answers in the answer blanks. Then color the drawing to suit your fancy. 1. Flexion 6. Protraction 2. Plantar flexion 7. Circumduction 3. Abduction 8. Adduction 4. Rotation 9. Extension 5. Pronation 10. Dorsiflexion
Chapter 8 Joints 177,~dJC _~E Figure 8.2