Chapter 9

1. Chapter 9 Articulations

2. Articulations • Point of contact between bones. • Joint- mostly very movable but some are immovable or only allow limited motions. • Movable joints allow complex, highly coordinated movements.

3. Classifications • Structural classification- joints are named according to: • Type of connective tissue • Presence of fluid filled joint capsules • Functional classification- • Synarthroses- immovable • Amphiarthroses- slightly movable • Diarthroses- freely movable

4. Fibrous Joints • Synarthroses • Bones of joints fit together closely, allowing little or no movement. • Syndesmoses- joints in which ligaments connect two bones. • Sutures- found only in skull; toothlike projections from adjacent bones interlock with each other. • Gomphoses- between root of a tooth and the alveolar process of mandible and maxilla.

5. Cartilaginous joints • Bones of joints are joined together by hyaline cartilage of fibrocartilage; allow very little motion.

6. Synovial joints • Freely movable joints • Structures: • Joint capsule • Synovial membrane • Articular cartilage • Joint cavity • Menisci • Ligaments • Bursae

7. Types of Synovial Joints • Uniaxial joints • Hinge joints- knee, elbow • Pivot joints- neck/vertebrae, radius • Biaxial joints • Saddle joints- thumbs • Condyloid joints- hips, shoulders

8. Types of Synovial Joints • Multiaxial joints • Ball and socket joint- shoulder, femur • Gliding joint- wrists, vertebrae

9. Humeroscapular Joint • Shoulder joint • Most mobile joint because of glenoid cavity • Glenoid labrum

10. Elbow Joint • Humeroradius joint • Humeroulnar joint • Both components of elbow joint surrounded by single joint capsule and stabilized by collateral ligaments.

11. Hip Joint • Stable joint

12. Knee Joint • Largest and one of the most complex and most frequently injured joints. • Tibiofemoral joint- supported by joint capsule, cartilage, ligaments, and tendons. • Permits flexion and extension

13. Ankle Joint • Hinge type of synovial joint • Articulation between lower ends of tibia and fibula and upper part of talus. • Joint is “mortise” or wedge-shaped. • Lateral malleolus lower than medial.

14. Measuring Range of Motion • Range of motion (ROM) assessment used to determine extent of joint injury. • ROM can be measured actively or passively; results of both by instrument called goniometer.

15. Angular Movement • Change in the size of angle between articulating bones. • Flexion- decreases angle between bones; bends or folds one part on another. • Extension- increases angle between two bones. • Hyperextension- extension between bones of a joint that is greater than normal. • Plantar flexion- increases angle between top of foot and front of leg.

16. Angular Movement • Dorsi flexion- decreases angle between top of foot and front of leg. • Abduction- moves part away from median plan of body. • Adduction- moves a part toward median plane of body.

17. Circular Movements • Rotation- pivoting a bone on its own axis. • Circumduction- moves a part so that its distal end moves in a circle. • Supination- turns the hand palm side-up. • Pronation- turns the hand palm side-down.

18. Gliding Movements • Simplest of all movements; articular surface of one bone moves over articular surface of another without any angular or circular movement.

19. Special Movements • Inversion- turning sole of foot inward. • Eversion- turning sole outward. • Protraction- moves a part forward. • Retraction- moves part backward. • Elevation- moves part up. • Depression- lowers a part.