Joints are classified based on their structure and function, as detailed below:
Classification by Function
Based on their functional characteristics, joints can be categorized into three main types:
- Synarthroses: These are immovable joints. They are designed for stability and do not allow for movement between bones. These joints are also known as fibrous joints.
- Amphiarthroses: These are slightly movable joints. They allow limited movement and are connected by cartilage. These joints are also known as cartilaginous joints.
- Diarthroses: These are freely movable joints. They allow a wide range of motion and are characterized by the presence of a joint cavity filled with synovial fluid. These are also known as synovial joints.
The following table summarizes the functional classification of joints:
| Joint Type | Movement | Description |
|---|---|---|
| Synarthroses | Immovable | Provide stability, often found where bones are fused. Also called fibrous joints. |
| Amphiarthroses | Slightly Movable | Allow limited movement, often involve cartilage. Also called cartilaginous joints. |
| Diarthroses | Freely Movable | Allow a wide range of motion, contain synovial fluid. Also called synovial joints. |
Examples of each joint type
- Synarthroses (Fibrous Joints): Examples include sutures in the skull.
- Amphiarthroses (Cartilaginous Joints): Examples include the pubic symphysis or the intervertebral discs in the spine.
- Diarthroses (Synovial Joints): Examples include the knee, shoulder, and hip joints.
Understanding these classifications is crucial for comprehending the mechanics of movement and the overall function of the skeletal system. The functional classification directly relates to the type of tissue that connects the bones at the joint:
- Fibrous connective tissue for synarthroses
- Cartilage for amphiarthroses
- Synovial fluid and complex structures for diarthroses.
