The Articular System: Joints, Classification, and Movements

2. Chapter 8 The Articular System

3. Introduction • Articulation: union between two or more bones • Can be mobile or immobile • Examples • Sutures between skull bones • Knee or elbow joint

4. The Classification of Joints: Structure and Function

5. Introduction • Joints are classified into three major groups based on: • Degree of movement allowed (function) • Type of material holding bones together (structure)

6. Synarthroses • No movement • Suture: bones connected by thin layer connective tissue (skull) • Syndesmosis: connected by ligaments between bones (radius and ulna) • Gomphosis: conical process in a socket (teeth)

7. Amphiarthroses • Slight movement • Symphysis: connected by disk of fibrocartilage (pubic symphysis) • Synchondrosis: connected by hyaline cartilage (growth plate between diaphysis and epiphyses)

8. Diarthroses or Synovial Joints • Free movement • Capsule with internal cavity • Capsule composition: fibrous cartilage, ligaments, tendons, muscle, synovial membranes • Functions: weight bearing and movement

9. Diarthroses or Synovial Joints (cont’d.)

10. Movements at Synovial Joints

11. Movements at Synovial Joints (cont’d.) • Flexion/Extension • Hyperextension: abnormal extension • Dorsiflexion/Plantar flexion • Abduction/Adduction • Rotation • Circumduction

12. Movements at Synovial Joints (cont’d.) • Supination/Pronation • Eversion/Inversion • Protraction/Retraction • Opposition/Reposition

13. The Six Types of Diarthroses or Synovial Joints

14. The Six Types of Diarthroses or Synovial Joints (cont’d.) • Ball-and-socket • Widest range of movement • Movement can occur in all planes and directions • Shoulder • Hip

15. The Six Types of Diarthroses or Synovial Joints (cont’d.) • Hinge • Convex surface fits into concave surface • Flexion and extension only • Knee • Elbow

16. The Six Types of Diarthroses or Synovial Joints (cont’d.) • Pivot • Rotation in one plane • Atlas and axis (cervical spine) • Rotation of the head

17. The Six Types of Diarthroses or Synovial Joints (cont’d.) • Condyloid (ellipsoidal) • Oval-shaped condyle fits into elliptical cavity • Motion in two planes at right angles • Radius and carpal bones

18. The Six Types of Diarthroses or Synovial Joints (cont’d.) • Saddle • Motion in two planes at right angles • Permits opposition of the thumb

19. The Six Types of Diarthroses or Synovial Joints (cont’d.) • Gliding • Gliding motion • Intervertebral joints in spine

20. Animation – Synovial Joints • [Insert synovial joints.swf]

21. Bursae

22. Bursae (cont’d.) • Closed sacs prevent friction between tissues • Synovial membrane lining • Subcutaneous: between skin and underlying bony processes • Subfascial: between overlying muscles • Subtendinous: between overlying tendons or bony projections

23. Summary • Discussed the three types of joints (synarthroses, amphiarthroses, and diarthroses or synovial joints) • Described the movements possible at synovial joints • Named the six types of synovial joints • Discussed the functions and types of bursae