Synovial fluid is a natural lubricant in some of your joints. It fills up a special membrane and helps reduce friction in joints where two bones move past each other. Your body regulates synovial fluid on its own, but health conditions that affect your joints can also affect the fluid in them.
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Synovial fluid is liquid lubricant in some of your joints. It’s also called joint fluid.
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Cleveland Clinic is a non-profit academic medical center. Advertising on our site helps support our mission. We do not endorse non-Cleveland Clinic products or services. Policy
Synovial fluid is held in place by the synovial membrane (synovium). They work together to protect your joints and help them move safely.
Synovial fluid’s main job is to lubricate your joints. The fluid slides between pieces of bone or cartilage to help them move smoothly and without rubbing against each other.
It’s like the oil in a car’s engine. The parts of an engine that move wouldn’t work well (and could even get damaged) without oil surrounding them to reduce friction. It’s the same way in your joints. Synovial fluid helps cushion the space between your bones. It also prevents them from rubbing together when you move.
Synovial fluid also helps transfer nutrients from your body to the cartilage and other tissues it touches.
Synovial fluid fills the inner layer of all the synovium in your body. It’s in any joint where two bones move together, including your:
Your body makes joint fluid from the plasma in your blood. It contains proteins and enzymes. Synovial fluid also has a lot of hyaluronic acid, which helps make it slick.
Synovial fluid is thick and slippery, kind of like egg whites. Your body automatically creates it to keep your joints lubricated.
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Anything that affects your joints can damage your synovial membranes and the fluid in them.
Arthritis is the most common issue that will affect your synovium and the joint it protects. Arthritis can cause more friction than your synovial fluid can cushion. Your body might try to make extra fluid, which can lead to swelling called effusion.
Other issues can affect your joint, including:
Visit a healthcare provider if you notice any changes or symptoms in your joints, including:
A healthcare provider may do a synovial fluid analysis to diagnose issues inside one of your joints. They’ll insert a thin needle into your affected joint and remove a sample of synovial fluid. This is also known as joint aspiration.
The sample of your synovial fluid can show signs of infections or other clues about damage or issues inside your joint.
A provider might do an aspiration to treat certain issues. Removing extra synovial fluid can relieve pain and swelling inside your joint.
You might remember learning how much water we’re made of in elementary school science class. But did you know some of the liquid in your body is in your joints? Synovial fluid helps your joints move smoothly. Injuries and conditions that affect your joints can throw your synovial fluid out of whack, too.
Visit a healthcare provider if you notice new or worsening joint pain, or if you have any symptoms that stop your joints from working like they should.
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Cleveland Clinic’s health articles are based on evidence-backed information and review by medical professionals to ensure accuracy, reliability and up-to-date clinical standards.
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