Table of Contents

• What Exactly is a Joint?
• How are Joints Classified?

What Exactly is a Joint?

A joint, in general, refers to the point where two or more elements intersect. In the context of anatomy, it is where two bones meet. It is a strong connection or articulation that binds the bones, teeth, and cartilage. It plays a crucial role in all kinds of bone-related movements. The force produced by muscles facilitates movement through various joints. The extent and flexibility of movement at distinct joints depend on several factors. Joints can be classified based on two main aspects.

How are Joints Classified?

The classification of a joint is largely determined by its functionality, specifically how much movement it enables:

• Immovable : Also known as synarthrosis, these joints do not permit any movement. The joints between the plates of a tortoise shell serve as an example of synarthrosis.
• Slightly movable : These joints, termed as amphiarthrosis, allow minimal movement. The joints between the vertebrae in a snake's body serve as an example of amphiarthrosis.
• Freely movable : These joints, known as diarthrosis, have the most range of motion. Examples of diarthrosis include the hip, wrist, and shoulder joints in humans.

Joints can also be classified based on the material composition within them.

• A fibrous joint is composed of tough collagen fibres , which do not permit any kind of movement. For instance, the joints in the skull of a human.
• Cartilaginous joints are composed of bones held together by cartilage. An example of this is the joints between the vertebrae in the human body .
• The most prevalent type of joint, the synovial joint , is characterized by a fluid-filled space between the smooth cartilage pads at the ends of the articulating bones. This arrangement facilitates movement. The synovial membrane that lines the capsule produces an oily fluid that lubricates the joints, reducing friction and wear & tear.