Joints

1. Joints AKA Articulations

2. Kinds of joints • Synarthroses – no movement • Amphiarthroses – slight movement • Diarthroses – free movement

3. synarthroses • Fibrous connective tissue grows between the bones • No significant movement between bones • Ex.sutures

4. amphiarthroses • Cartilage connects the bones • Ex. Symphysis pubis, vertebrae • Herniated disk – when the disk between the vertebrae is pushed into the spinal canal and pushes on the spinal cord

5. diarthroses • Includes most joints, allows for movement

6. Types of diarthrotic joints • Ball and socket – hip and shoulder, widest range of motion • Hinge – movement in 2 directions (flexion and extension), elbow, knee, fingers • Pivot – small projection of 1 bone pivots in an arch of another (rotation) atlas/axis • Saddle joints – metacarpal bone of thumb and carpal bone, only 1 pair, opposable thumb • Gliding – least movable, gliding movements between vertebrae • Condyloid – oval projection fits in elliptical socket, wrist

7. Diarthrotic Joint – the Knee

8. Diartrotic joint structure • Joint capsule – fibrous connective tissue, fits over 2 connecting bones, lined with synovial fluid. • Ligament – connect bone to bone, fibrous connective tissue • Articular cartilage – layer over ends of bones, protection • Synovial membrane – secretes fluid, allows for easier movement, less friction

9. Joint movements • Flexion – reduce angle of joint • Extension –increase angle of joint • Rotation – spin a bone relative to another • Circumduction- moving distal end while keeping proximal end stable • Abduction – move away from midline, increase angle of joint • Adduction – moving part toward midline, decrease angle of joint