Joints!

Joints may be classified structurally or functionally.

Structural Classification focuses on the material binding the bones together and whether or not a joint cavity is present. There are three (3) structural classifications:

• Fibrous- i.e. skull joints, dense, fibrous connective tissue.
• Cartilaginous- have cartilage between bones, allowing more flexibility.
• Synovial- have joint cavities and allow free movement.

Functional Classification is based on the amount of movement allowed by the joint. There are three (3) functional classifications as well:

• Synarthroses- immovable.
• Diarthroses- slightly movable.
• Amphiarthroses- freely movable.

Examples:

Synarthroses/Fibrous Joints

• Sutures-skull.
• Syndesmoses- articulation between tibia and fibula.
• Gomphoses- teeth.

Cartilaginous/Amphiarthroses

• Epiphyseal Plate
• Pubic Symphysis

Synovial Joints

Synovial joints are diathroses. This is the most common joint type within our body, has several components, and just as many types possible.

5 Components:

1. Articular Cartilage-acts as shock absorbers for bones.
2. Fibrous Capsule- holds bones close to each other and helps prevent hyperextensions.
3. Joint Cavity- holds the synovial fluid.
4. Ligaments- prevent twisting and shearing forces. They connect bone to bone.
5. Synovial Fluid- lubricates the joint.

Types:

• Hinge joints- i.e elbow.
• Planar joints- i.e.
• Pivot Joints- i.e.
• Condyloid Joints- i.e.
• Saddle Joint- i.e. thumb.
• Ball & Socket Joints: i.e. leg/hip, shoulder/arm.