Skeletal System 4

1. Skeletal System 4 Honors Anatomy to be copied

2. Joints & Homeostasis • Joints contribute to homeostasis by holding bones together in ways that allow movement & flexibility

3. Joints • aka: “articulation” or “arthrosis” • a point of contact between 2 bones, a bone & cartilage, or between a bone & tooth

4. Joint Classification • 1. structural classification • based on anatomical characteristics • Fibrous joints • Cartilagenous joints • Synovial joints • 2. functional classification • based on type of movement they permit • Synarthrosis • Amphiarthrosis • Diarthrosis

5. Fibrous Joints • Articulating bones held very closely together by fibrous CT • 3 types: • Sutures • skull bones • Syndesmoses • interosseous membrane • Gomphoses • dentoalveolar joint

6. Gomphoses

7. Cartilagenous Joints • allows little or no movement • bones are tightly connected by either hyaline cartilage or fibrocartilage • 2 types: • Synchondoses • hyaline cartilage connects bones • epiphyseal plate • Symphyses • fibrocartilage connects bone • pubic symphysis

8. Symphyses

9. Synovial Joints • distinguishing characteristics: • synovial joint cavity • filled with synovial fluid • bones covered by articular cartilage • reduces friction

10. Synovial Fluid • secreted by synovial membrane • viscous, clear, pale yellow fluid • forms film over surfaces w/in articular capsule • functions: • reduce friction • absorbing shocks • supporting chondrocytes in w/in articular cartilage

11. By the way…. • cracking sounds heard as joints move or popping sounds people make when the “crack” their knuckles explanation: • When synovial cavity expands  creates partial vacuum  suction from that draws CO2 & O2 out of blood vessels in synovial membrane  form bubbles in synovial fluid  bubbles pop

12. Sprains • a forcible wrenching or twisting of a joint that stretches or tears ligaments but does not dislocate the bones • occurs when ligaments are stressed beyond their capacity • may have associated damage to surrounding blood vessels, muscles, tendons, or nerves

13. Strains • stretched or partially torn muscle • often due to muscle contracting suddenly & powerfully

14. Bursae • saclike structures situated to alleviate friction in some joints • filled with fluid similar to synovial fluid • located between: • skin & bones • tendons & bones • muscles & bones • ligaments & bones

15. Bursitis • inflammation of a bursa • usually caused by irritation from repeated, excessive exertion of a joint • or by: trauma, infection (syphilis or TB), RA • symptoms: pain, swelling, tenderness, limited movement

16. Types of Movements @ Synovial Joints • 1. Gliding • relatively flat surfaces move back-and-forth & side-to-side

17. Types of Movements @ Synovial Joints • 2. flexion/extension/ hyperextension: • opposite movements • flexion: decrease in angle between articulating bones • extension: increase in angle between articulating bones • hyperextension: continuation of extension beyond the anatomical position

19. Types of Movements @ Synovial Joints • 3. abduction/adduction/ circumduction • abduction: movement of bone away from midline • adduction: movement of bone toward midline • circumduction: movement of distal end of a body part in a circle

21. Types of Movements @ Synovial Joints • 4. elevation/depression: • elevation: upward movement of part of body (closing mouth, shrugging shoulders) • depression: downward movement of part of body (opening mouth, returning elevated shrugged shoulders to anatomical position)

23. Types of Movements @ Synovial Joints • 5. protraction/retraction • protraction: movement of part of body anteriorly in transverse plane • retraction: returning a protracted part of body to anatomical position

25. Types of Movements @ Synovial Joints • 6. inversion/ eversion • inversion: movement of soles medially @ intertarsal joints (soles face each other) • eversion: movement of soles laterally @ intertarsal joints

27. Types of Movements @ Synovial Joints • 7. dorsiflexion/ plantar flexion • dorsiflexion: bending foot @ ankle in direction of dorsum (superior surface) • plantar flexion: bending foot @ ankle in direction of plantar surface

29. Types of Movements @ Synovial Joints • 8. supination/pronation • supination: movement of forearm in which palm is turned anteriorly • pronation: movement of forearm in which distal end of radius crosses over distal end ulna & palm is turned posteriorly

31. Types of Movements @ Synovial Joints • 9. opposition • movement of thumb in which thumb moves across palm to touch tips of the fingers on same hand

33. Ball - & - Socket Joint • ball-like surface of one bone fits into a cuplike depression of another bone • permits movement around 3 axis + all directions in between • flexion • extension • abduction • adduction • circumduction • rotation

35. Homeostatic Imbalances • Rheumatoid Arthritis (RA) • autoimmune disease: immune system attacks joint linings • characterized by: • inflammation of joint  swelling, pain, loss of function • usually bilateral joints involved but may not be to same degree

36. Medical Terminology • arthralgia: pain in a joint • subluxation: partial or incomplete dislocation of a joint