The Skeletal System Part 4 Joints

1. The Skeletal SystemPart 4Joints Honors Anatomy & Physiology

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. Parts of a Synovial Joint

11. 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

12. 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

13. 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

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

15. 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

16. Bursae

17. 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

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

20. 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

22. 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

24. 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)

26. 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

28. 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

30. 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

32. 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

34. 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

36. Identify Movements

37. 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

40. 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

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