Arthritis – Structure And Function of Joints

The structure of our body makes it possible for many bones to meet with each other and their meeting place is called a joint. The main components of a joint are

• Bones
• Cartilages
• Membranes
• Capsules and Ligaments
• Muscles, tendons and bursa
• Fibrous Joints

Bones

Bones are living tissues. They are made up of calcium phosphate and other minerals. They can change shape or break under abnormal stress. Diseases like arthritis can also damage them. The shape of the bone and type of joint decides the movement. In hinge joints like in elbow, the movement is in one direction only while in case of a ball socket joint as in hip, the movement is in many directions.

Cartilages

Cartilages are white tissues. They act as shock absorbers and allow smooth movement between two bone ends. Some complex joints like knees have extra pads of cartilage. Cartilages also make up the dishes between the vertebrae. Once damaged, cartilages are usually difficult to be repaired.

Membranes

Membrane surrounding the joint is called synovium. It produces small amount of sticky fluid of proper consistency, which lubricates the joint and provides nutrition to cartilages.