The Articular System Joints Chapter 8 The Articular System Joints

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

The Classification of Joints: Structure and Function

Introduction Joints are classified into three major groups based on: Degree of movement allowed (function) Type of material holding bones together (structure) 1-synarthroses 2- Amphiarthroses 3- Diarthroses or synovial joints

Diarthroses or Synovial Joints (cont’d.)

Movements at Synovial Joints

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

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

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.

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

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.

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.

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.

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.

The Six Types of Diarthroses or Synovial Joints

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

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

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

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

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

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

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

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

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

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

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

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