1. Articulations Chapter 6

2. Classification of Joints (Articulations):
Joint- Where two bones interact
Three functional classes of joints
Synarthroses
Immovable – e.g., sutures
Amphiarthroses
Slightly movable – e.g., pubic symphysis, distal radius/ulna
Diarthroses
Freely movable – e.g., shoulder, elbow etc.

3. Classification of Joints (Articulations):
Three structural classes of joints
Fibrous
No space between articulating bones; held together by dense connective tissue – e.g., sutures, distal radius/ulna
May be functionally synarthroses or amphiarthroses
Cartilagenous
No space between articulating bones; held together by cartilage – e.g., pubic symphysis
May be funtionally synarthroses or amphiarthroses
Synovial
Space (synovial/joint cavity) between articulating bones – e.g., shoulder, elbow etc.
Functionally are diarthroses

4. The Structure of Synovial Joints

5. The Structure of Synovial Joints

6. Movements ocurring at synovial joints
Flexion
Extension
Hyperextension

7. Lateral flexion Abduction Adduction Rt. lateral flexion
Lt. lateral flexion

8. Rotation:
Left/Right
Medial (internal)
Lateral (external)

9. Pronation
Supination

10. Dorsiflexion/Plantarflexion
Inversion/Eversion
Elevation/Depression
Protraction/Retraction
Opposition

11. Movement at synovial joints occurs through contraction of skeletal muscles
When skeletal muscles contract, they pull on bones of the skeleton at their attachment points, creating movement in a particular direction (or directions)

12. Origin - Muscle attachment that remains
fixed
Insertion - Muscle attachment that moves
Action - What movement a muscle produces. Movement usually occurs at joints i.e. flexion, extension, abduction, etc.

13. For muscles to create a movement, they can only pull, not push
Muscles in the body rarely work alone, & are usually arranged in groups surrounding a joint
A muscle that contracts to create the desired action is known as an agonist or prime mover
A muscle that helps the agonist is a synergist
A muscle that opposes the action of the agonist, therefore undoing the desired action is an antagonist

14. Skeletal muscle movements
Flexion/extension
Abduction/adduction
Rotation – left/right; internal(medial)/external(lateral)
Pronation/supination
Elevation/depression
Protraction/retraction
Dorsiflexion/plantarflexion
Inversion/eversion
*note: muscles of facial expression (e.g. orbicularis oculi; orbicularis oris) produce movements of the features of the face, and therefore the actions use more descriptive terminology