Joints come in many shapes, sizes and types throughout your body. They give your skeleton its shape and help you move. No matter what you’re doing throughout your day, your joints make it possible. Talk to a healthcare provider as soon as you notice any changes (especially pain) in your joints.
A joint is any place in your body where two bones meet. They’re part of your skeletal system. You might see joints referred to as articulations.
You have hundreds of joints throughout your body, and many ways healthcare providers group them together (classification). Joints are usually classified based on:
Joints support your body from head to toe. Whether it’s a joint you’re aware of (like your ankle) or some you’ve maybe never heard of (like the joints that hold your skull together), all of your joints help you use your body every day.
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Joints support your body. They help you sit, stand and move.
Some joints provide structural support. Others let you move. Depending on how much a joint moves, it fits into one of three categories:
Your joints are made of bones and the connective tissues that hold them together, including:
Healthcare providers classify joints into three categories depending on how much connective tissue they contain:
Fibrous joints aren’t very flexible. Some of them don’t move at all. Their name reflects what they’re made of — thick connective tissue that’s tightly woven together like fiber. Fibrous joints usually contain a lot of collagen.
There are three types of fibrous joints, including:
Cartilaginous joints are cushioned by a layer of cartilage that joins the bones together. Most cartilaginous joints have some movement, but don’t move far or in many directions.
The joints where your ribs meet your sternum (breastbone) are cartilaginous. The pubic symphysis joint that joins your left and right pelvic bones together is another cartilaginous joint.
Synovial joints have the most freedom to move. They’re made of a cavity in one bone that another bone fits into. Slippery hyaline cartilage covers the ends of bones that make up a synovial joint. A synovial membrane — a fluid-filled sac that lubricates and protects the joint — lines the space between the bones. This extra cushioning helps synovial joints move with as little friction as possible.
There are six types of synovial joints:
Joints can be affected by anything that damages your bones or connective tissue, including:
People with autoimmune diseases often experience symptoms in their joints. Some of the most common include:
Your joints can also be damaged by traumas like falls and car accidents. Injuries that affect joints include:
Which symptoms you’ll have depends on which condition or injury you’re experiencing. Many joint issues cause symptoms like:
Which tests you’ll need depends on the symptoms you’re experiencing. Visit a healthcare provider as soon as you notice changes or new pain in one of your joints. Some of the most common tests providers use to diagnose joint issues include:
The best way to take care of your joints is to maintain good overall health, including:
Experts often disagree on exactly how many joints are in the human body. Most experts define a joint as any place two bones meet. Others define joints differently, saying joints should only be considered places where two bones meet that move.
Depending on which definition you use, adults have around 350 joints.
A note from Cleveland Clinic
You use your joints every time you do anything, from sitting down after a long day to scrolling through this article on your phone. They’re the nuts and bolts that help your body hold its shape and perform any movement you need it to.
Because they’re so vital to your daily routine, any issue with your joints can be a huge pain (sometimes literally). Visit a healthcare provider if you’re experiencing new pain or other symptoms in your joints.
Last reviewed by a Cleveland Clinic medical professional on 07/18/2023.
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