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9 Articulations

9 Articulations. An Introduction to Articulations. Learning Outcomes 9-1 Contrast the major categories of joints, and explain the relationship between structure and function for each category.

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9 Articulations

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  1. 9 Articulations

  2. An Introduction to Articulations Learning Outcomes 9-1 Contrast the major categories of joints, and explain the relationship between structure and function for each category. 9-2 Describe the basic structure of a synovial joint, and describe common synovial joint accessory structures and their functions. 9-3 Describe how the anatomical and functional properties of synovial joints permit movements of the skeleton. 9-4 Describe the articulations between the vertebrae of the vertebral column. 9-5 Describe the structure and function of the shoulder joint and the elbow joint. 9-6 Describe the structure and function of the hip joint and the knee joint. 9-7 Describe the effects of aging on articulations, and discuss the most common age-related clinical problems for articulations. 9-8 Explain the functional relationships between the skeletal system and other body systems.

  3. An Introduction to Articulations Articulations Body movement occurs at joints (articulations) wheretwo bones connect Joint Structure Determines direction and distance of movement (rangeof motion or ROM) Joint strength decreases as mobility increases Two Methods of Classification • Functional classification is based on range of motion of the joint • Structural classificationrelies on the anatomical organization of the joint

  4. 9-1 Classification of Joints Functional Classifications Synarthrosis (immovable joint) Amphiarthrosis (slightly movable joint) Diarthrosis (freely movable joint) Structural Classifications Bony Fibrous Cartilaginous Synovial

  5. Table 9-1 Functional and Structural Classifications of Articulations 1 Functinally, why are sutures classified as synarthroses, and syndesmoses as amphiarthroses?

  6. Table 9-1 Functional and Structural Classifications of Articulations

  7. Table 9-1 Functional and Structural Classifications of Articulations 2 What is the functional classification of synovial joints?

  8. 9-1 Classification of Joints Synarthroses (Immovable Joints) Are very strong Edges of bones may touch or interlock Four types of synarthrotic joints • Suture • Gomphosis • Synchondrosis • Synostosis

  9. 9-1 Classification of Joints Amphiarthroses More movable than synarthrosis Stronger than freely movable joint Two types of amphiarthroses • Syndesmosis Bones connected by ligaments • Symphysis Bones separated by fibrocartilage

  10. 9-1 Classification of Joints Synovial Joints (Diarthroses) Also called movable joints. Found at the ends of long bones. Within articular capsules (Pad articulating surfaces within articular capsules. They prevent bones from touching. They are lubricated by synovial fluid. They are lined with synovial membrane. They prevent friction. Synovial Fluid Contains slippery proteoglycans secreted by fibroblasts Functions of synovial fluid • Lubrication • Nutrient distribution • Shock absorption

  11. 9-2 Synovial Joints Accessory Structures Cartilages Cushion the joint Fibrocartilage pad called a meniscus (or articular disc; plural, menisci) Fat pads Superficial to the joint capsule Protect articular cartilages Ligaments Support, strengthen joints Sprain – ligaments with torn collagen fibers Tendons Attach to muscles around joint Help support joint Bursae Singular, bursa, a pouch Pockets of synovial fluid Cushion areas where tendons or ligaments rub

  12. 9-2 Synovial Joints Factors That Stabilize Synovial Joints Prevent injury by limiting range of motion Collagen fibers (joint capsule, ligaments) Articulating surfaces and menisci Other bones, muscles, or fat pads Tendons of articulating bones

  13. 9-2 Synovial Joints Injuries Dislocation (luxation) Articulating surfaces forced out of position Damages articular cartilage, ligaments, joint capsule Subluxation A partial dislocation

  14. 9-3 Movements Three Types of Dynamic Motion • Linear movement (gliding) • Angular movement • Rotation Planes (Axes) of Dynamic Motion Monaxial (1 axis) Biaxial (2 axes) Triaxial (3 axes) Types of Movement at Synovial Joints Terms describe: Plane or direction of motion Relationship between structures

  15. 9-3 Movements Types of Movement at Synovial Joints Gliding Movement (Two surfaces slide past each other. Between carpals and tarsals). Angular Movement Flexion (Angular motion. Anterior-posterior plane. Reduces angle between elements) Extension (Angular motion. Anterior-posterior plane. Increases angle between elements) Abduction (Angular motion. Frontal plane. Moves AWAY from longitudinal axis) Adduction (Angular motion. Frontal plane. Moves TOWARD longitudinal axis) Hyperextension (Angular motion. Extension past anatomical position)

  16. 9-3 Movements Types of Movement at Synovial Joints Rotation Direction of rotation from anatomical position Relative to longitudinal axis of body Left or right rotation Medial rotation (inward rotation). Rotates toward axis. Lateral rotation (outward rotation). Rotates away from axis. Pronation Rotates forearm, radius over ulna Supination Forearm in anatomical position

  17. 9-3 Movements Special Movements Inversion—twists sole of foot medially Eversion—twists sole of foot laterally Dorsiflexion—flexion at ankle (lifting toes) Plantar flexion—extension at ankle (pointing toes) Opposition—thumb movement toward fingers or palm (grasping) Reposition—opposite of opposition Protraction—moves anteriorly in the horizontal plane (pusing forward) Retraction—opposite of protraction. Moving anteriorly (pulling back) Elevation—moves in superior direction (up) Depression—moves in inferior direction (down) Lateral flexion—bends vertebral column from side to side

  18. Study Points Handout • 3 What are two examples of joints that permit gliding movements? • 4 What are two examples of flexion that do not occur along the sagittal plane? • 5 In what way is considering adduction as “adding your limb to your trunk” an effective learning device? • 6 Which movements in continuous sequence produce circumduction?

  19. 9-3 Movements Classification of Synovial Joints by Shape Gliding Hinge Pivot Condylar Saddle Ball-and-socket

  20. 9-3 Movements Gliding Joints Flattened or slightly curved faces. Limited motion (nonaxial) Hinge Joints Angular motion in a single plane (monaxial) Pivot Joints Rotation only (monaxial) Condylar Joints Oval articular face within a depression. Motion in two planes (biaxial) Saddle Joints Two concave, straddled (biaxial) Ball-and-socket Joints Round articular face in a depression (triaxial)

  21. 9-3 Movements Joints A joint cannot be both mobile and strong The greater the mobility, the weaker the joint Mobile joints are supported by muscles and ligaments, not bone-to-bone connections

  22. 9-4 Intervertebral Articulations Intervertebral Articulations C2 to L5 spinal vertebrae articulate: At inferior and superior articular processes (gliding joints) Between adjacent vertebral bodies (symphyseal joints) Intervertebral Discs Pads of fibrocartilage Separate vertebral bodies Anulus fibrosus Tough outer layer Attaches disc to vertebrae Nucleus pulposus Elastic, gelatinous core Absorbs shocks

  23. Figure 9-7 Intervertebral Articulations Superiorarticularfacet IntervertebralDisc Vertebral end plate Intervertebralforamen Anulus fibrosus Ligamentumflavum Nucleus pulposus Spinal cord Posteriorlongitudinalligament Spinal nerve Interspinousligament Supraspinousligament Anteriorlongitudinalligament

  24. 9-4 Intervertebral Articulations Damage to Intervertebral Discs Slipped disc Bulge in anulus fibrosus Invades vertebral canal Herniated disc Nucleus pulposus breaks through anulus fibrosus Presses on spinal cord or nerves Movements of the vertebral column: Flexion Extension Lateral Flexion Rotation

  25. 9-5 The Shoulder Joint TheShoulder Joint Also called the glenohumeraljoint Allows more motion than any other joint Is the least stable The Elbow Joint Humero-ulnar joint A stable hinge joint With articulations involving humerus, radius, and ulna Humeroradial joint Smaller articulation Capitulum of humerus and head of radius 8 Why does the shoulder joint have more freedom of movement than any other joint of the body?

  26. 9-6 The Hip Joint The Hip Joint Also called coxal joint Strong ball-and-socket diarthrosis Wide range of motion The Knee Joint A complicated hinge joint Transfers weight from femur to tibia Articulations of the knee joint Two femur–tibia articulations At medial and lateral condyles One between patella and patellar surface of femur

  27. 9-7 Effects of Aging on Articulations Degenerative Changes Rheumatism A pain and stiffness of skeletal and muscular systems Arthritis All forms of rheumatism that damage articular cartilages of synovial joints Osteoarthritis Caused by wear and tear of joint surfaces, or genetic factors affecting collagen formation Generally in people over age 60

  28. 9-7 Effects of Aging on Articulations Rheumatoid Arthritis An inflammatory condition Caused by infection, allergy, or autoimmune disease Involves the immune system Gouty Arthritis Occurs when crystals (uric acid or calcium salts) Form within synovial fluid Due to metabolic disorders

  29. 9-7 Effects of Aging on Articulations Joint Immobilization Reduces flow of synovial fluid Can cause arthritis symptoms Treated by continuous passive motion or CPM (therapy) Bones and Aging Bone mass decreases Bones weaken Increases risk of hip fracture, hip dislocation, or pelvic fracture Bone Recycling Living bones maintain equilibrium between: Bone building (osteoblasts) And breakdown (osteoclasts)

  30. 9-8 Integration with Other Systems Factors Affecting Bone Strength • Age • Physical stress • Hormone levels • Calcium and phosphorus uptake and excretion • Genetic and environmental factors

  31. 9-8 Integration with Other Systems Bones Support Body Systems Support and protect other systems Store fat, calcium, and phosphorus Manufacture cells for immune system Disorders in other body systems can cause: Bone tumors Osteoporosis Arthritis Rickets (vitamin D deficiency)

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