1. Honors Anatomy to be copied
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 intertarsal joints (soles face each other)
eversion: movement of soles intertarsal joints

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