1. The Articular System Joints
Chapter 8
The Articular System
Joints

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

3. The Classification of Joints: Structure and Function

4. Introduction Joints are classified into three major groups based on:
Degree of movement allowed (function)
Type of material holding bones together (structure)
1-synarthroses( joints that do not allow movements)
2- Amphiarthroses(joints that allow only slight movement.
3- Diarthroses or synovial joints( Freely moving joints or articulations)

5. Movements at Synovial Joints

6. Movements at Synovial Joints (cont’d.)
Flexion/extension
Hyperextension: abnormal extension
Dorsiflexion/plantar flexion
Abduction/adduction
Rotation
Circumduction

7. Movements at Synovial Joints (cont’d.)
Supination/pronation
Eversion/inversion
Protraction/retraction
Opposition/reposition

9. Flexion and extension
Flexion : The act of bending or decreasing the angle between bones.
Extension: The act of increasing the angle between bones and is the opposite of flexion.

10. Hyperextension
Hyperextension : It increases the joint angle beyond the anatomic position.

11. Abduction and adduction
Abduction: Is moving the bones away from the midline of the body.
Adduction: Is moving the bone toward the midline of the body.

12. Rotation and circumduction
Rotation: Is the act of moving the bone around a central axis.
Circumduction: Is moving the bone in such a way that the end of the bone describe the circle in the air and the sides of the bone describe a cone in the air.

13. Supination and pronation
Supination: Is moving the bones of the forearm so that the radius and ulna are in parallel.
Pronation :Is moving the bones of the forearm so that the radius and ulna are not parallel.

14. Eversion and inversion
Eversion : Is the moving the sole of the foot outward at the ankle.
Inversion: Is moving the sole of the foot inward at the ankle.

16. Other movements
Protraction : Is moving a part of the body forward on a plane parallel to the ground.
Retraction : Is moving a part of the body backward on a plane parallel to the ground.
Elevation :Is raising a part of the body.
Depression : Is lowering a part of the body.

17. Opposition
Opposition : Is movement that occurs only with the thumb. It occurs when the tip of the thumb and the fingers are brought together.

18. Reposition
Reposition : When the digits return their normal positions.

19. Dorsiflexion and plantar flexion
Dorsiflexion : Is raising the foot up at the ankle joint.
Plantar flexion: Is pushing the foot down at the ankle joints, actions we do when walking.

20. Diagrams

23. The Six Types of Diarthroses or Synovial Joints

24. 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

25. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Ball-and-socket

26. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Hinge
Convex surface fits into concave surface
Flexion and extension only
Knee
Elbow
 Hinge joints are formed between two or more bones where the bones can only move along one axis to flex or extend.

27. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Hinge

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

29. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Pivot

30. 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
This permits movement in two planes, allowing flexion, extension, adduction, abduction, and circumduction.

31. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Condyloid (ellipsoidal)

32. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Saddle
Motion in two planes at right angles
Permits opposition of the thumb
Saddle joints provide stability to the bones while providing more flexibility than a hinge or gliding joint.

33. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Saddle

34. The Six Types of Diarthroses or Synovial Joints (cont’d.)
A gliding joint, also known as a plane joint or planar joint, formed between bones that meet at flat or nearly flat articular surfaces. Gliding joints allow the bones to glide past one another in any direction along the plane of thejoint – up and down, left and right, and diagonally.
Gliding motion
Intervertebral joints in spine

35. The Six Types of Diarthroses or Synovial Joints (cont’d.)
Gliding