Your joints are places where two or more bones come together. Your shoulders, elbows, hips, knees, and knuckles are all joints. Your spine has joints, too.

But joints are more than bones. They include the soft tissues around them, such as cartilage, tendons and ligaments. Cartilage is the hard slippery flexible tissue that covers the ends of your bones at a joint. Tendons are tough, flexible bands that connect your muscles to your bones so you can move your joints. Ligaments connect the bones of the joint to each other to keep them stable when you move.

Joint disorders are diseases or injuries that affect your joints. Injuries can happen because of overuse of a joint. Or you could have a sudden injury, such as an accident or a sports injury.

Your ankle bone and the ends of your two lower leg bones make up the ankle joint. Your ligaments, which connect bones to one another, stabilize and support it. Your muscles and tendons move it.

The most common ankle problems are sprains and fractures. A sprain is an injury to the ligaments. It may take a few weeks to many months to heal completely. A fracture is a break in a bone. You can also injure other parts of the ankle such as tendons, which join muscles to bone, and cartilage, which cushions your joints. Ankle sprains and fractures are common sports injuries.

If you feel pain and stiffness in your body or have trouble moving around, you might have arthritis. Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Over time, a swollen joint can become severely damaged. Some kinds of arthritis can also cause problems in your organs, such as your eyes or skin.

Types of arthritis include

• Osteoarthritis is the most common type of arthritis. It's often related to aging or to an injury.
• Autoimmune arthritis happens when your body's immune system attacks healthy cells in your body by mistake. Rheumatoid arthritis is the most common form of this kind of arthritis.
• Juvenile arthritis is a type of arthritis that happens in children.
• Infectious arthritis is an infection that has spread from another part of the body to the joint.
• Psoriatic arthritis affects people with psoriasis.
• Gout is a painful type of arthritis that happens when too much uric acid builds up in the body. It often starts in the big toe.

A bursa is a small, fluid-filled sac that acts as a cushion between a bone and other moving parts, such as muscles, tendons, or skin. Bursitis occurs when a bursa becomes inflamed. People get bursitis by overusing a joint. It can also be caused by an injury. It usually occurs at the knee or elbow. Kneeling or leaning your elbows on a hard surface for a long time can make bursitis start. Doing the same kinds of movements every day or putting stress on joints increases your risk.

Symptoms of bursitis include pain and swelling. Your doctor will diagnose bursitis with a physical exam and tests such as x-rays and MRIs. He or she may also take fluid from the swollen area to be sure the problem isn't an infection.

Treatment of bursitis includes rest, pain medicines, or ice. If there is no improvement, your doctor may inject a drug into the area around the swollen bursa. If the joint still does not improve after 6 to 12 months, you may need surgery to repair damage and relieve pressure on the bursa.

Cartilage is the tough but flexible tissue that covers the ends of your bones at a joint. It also gives shape and support to other parts of your body, such as your ears, nose and windpipe. Healthy cartilage helps you move by allowing your bones to glide over each other. It also protects bones by preventing them from rubbing against each other.

Injured, inflamed, or damaged cartilage can cause symptoms such as pain and limited movement. It can also lead to joint damage and deformity. Causes of cartilage problems include

• Tears and injuries, such as sports injuries
• Genetic factors
• Other disorders, such as some types of arthritis

Osteoarthritis results from breakdown of cartilage.

Your connective tissue supports many different parts of your body, such as your skin, eyes, and heart. It is like a "cellular glue" that gives your body parts their shape and helps keep them strong. It also helps some of your tissues do their work. It is made of many kinds of proteins. Cartilage and fat are types of connective tissue.

Over 200 disorders that impact connective tissue. There are different types:

• Genetic disorders, such as Ehlers-Danlos syndrome, Marfan syndrome, and osteogenesis imperfecta
• Autoimmune disorders, such as lupus and scleroderma
• Cancers, like some types of soft tissue sarcoma

Each disorder has its own symptoms and needs different treatment.

Dislocations are joint injuries that force the ends of your bones out of position. The cause is often a fall or a blow, sometimes from playing a contact sport. You can dislocate your ankles, knees, shoulders, hips, elbows and jaw. You can also dislocate your finger and toe joints. Dislocated joints often are swollen, very painful and visibly out of place. You may not be able to move it.

A dislocated joint is an emergency. If you have one, seek medical attention. Treatment depends on which joint you dislocate and the severity of the injury. It might include manipulations to reposition your bones, medicine, a splint or sling, and rehabilitation. When properly repositioned, a joint will usually function and move normally again in a few weeks. Once you dislocate a shoulder or kneecap, you are more likely to dislocate it again. Wearing protective gear during sports may help prevent dislocations.

Your elbow joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the elbow joint move. When any of these structures is hurt or diseased, you have elbow problems.

Many things can make your elbow hurt. A common cause is tendinitis, an inflammation or injury to the tendons that attach muscle to bone. Tendinitis of the elbow is a sports injury, often from playing tennis or golf. You may also get tendinitis from overuse of the elbow.

Other causes of elbow pain include sprains, strains, fractures, dislocations, bursitis and arthritis. Treatment depends on the cause.

Your hip is the joint where your femur (thigh bone) meets your pelvis (hip bone). There are two main parts: a ball at the end of the femur, which fits in a socket in the pelvis. Your hip is known as a ball-and-socket joint. This is because you have a ball at the end of your femur, and it fits into a socket in your pelvis. This makes your hips very stable and allows for a wide range of motion. When they are healthy, it takes great force to hurt them. However, playing sports, running, overuse, or falling can sometimes lead to hip injuries such as:

• Strains
• Bursitis
• Dislocations
• Fractures (broken bones)

Certain diseases also lead to hip injuries or problems. Osteoarthritis can cause pain and limited motion. Osteoporosis of the hip causes weak bones that break easily. Both of these are common in older people.

Another problem is hip dysplasia, where the ball at the end of the femur is loose in the hip socket. It can cause hip dislocation. Babies who have hip dysplasia are usually born with it, but sometimes they develop it later.

Treatment for hip disorders may include rest, medicines, physical therapy, or surgery, including hip replacement.

Most kinds of arthritis cause pain and swelling in your joints. Joints are places where two bones meet, such as your elbow or knee. Infectious arthritis is an infection in the joint. The infection comes from a bacterial, viral, or fungal infection that spreads from another part of the body. Symptoms of infectious arthritis include

• Intense pain in the joint
• Joint redness and swelling
• Chills and fever
• Inability to move the area with the infected joint

One type of infectious arthritis is reactive arthritis. The reaction is to an infection somewhere else in your body. The joint is usually the knee, ankle, or toe. Sometimes, reactive arthritis is set off by an infection in the bladder, or in the urethra, which carries urine out of the body. In women, an infection in the vagina can cause the reaction. For both men and women, it can start with bacteria passed on during sex. Another form of reactive arthritis starts with eating food or handling something that has bacteria on it.

To diagnose infectious arthritis, your health care provider may do tests of your blood, urine, and joint fluid. Treatment includes medicines and sometimes surgery.

Juvenile arthritis (JA) is arthritis that happens in children. It causes joint swelling, pain, stiffness, and loss of motion. It can affect any joint, but is more common in the knees, hands, and feet. In some cases it can affect internal organs as well.

The most common type of JA that children get is juvenile idiopathic arthritis. There are several other forms of arthritis affecting children.

One early sign of JA may be limping in the morning. Symptoms can come and go. Some children have just one or two flare-ups. Others have symptoms that never go away. JA can cause growth problems and eye inflammation in some children.

No one knows exactly what causes JA. Most types are autoimmune disorders. This means that your immune system, which normally helps your body fight infection, attacks your body's own tissues.

JA can be hard to diagnose. Your health care provider may do a physical exam, lab tests, and x-rays. A team of providers usually treats JA. Medicines and physical therapy can help maintain movement and reduce swelling and pain. They may also help prevent and treat complications.

Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking.

Knee problems are very common, and they occur in people of all ages. Knee problems can interfere with many things, from participation in sports to simply getting up from a chair and walking. This can have a big impact on your life.

The most common disease affecting the knee is osteoarthritis. The cartilage in the knee gradually wears away, causing pain and swelling.

Injuries to ligaments and tendons also cause knee problems. A common injury is to the anterior cruciate ligament (ACL). You usually injure your ACL by a sudden twisting motion. ACL and other knee injuries are common sports injuries.

Treatment of knee problems depends on the cause. In some cases your doctor may recommend knee replacement.

What is osteoarthritis?

Osteoarthritis, sometimes called OA, is a type of arthritis that only affects the joints, usually in the hands, knees, hips, neck, and lower back. It's the most common type of arthritis.

In a healthy joint, the ends of the bones are covered with a smooth, slippery tissue called cartilage. The cartilage pads the bones and helps them glide easily when you move the joint. With osteoarthritis, the cartilage breaks down and becomes rough. Sometimes, all the cartilage wears away and the bones rub together. Bumps of extra bone called bone spurs may grow in the joint area.

There is no cure for osteoarthritis. It usually gets worse slowly. But there's a lot you can do to manage the symptoms.

What are the symptoms of osteoarthritis?

Osteoarthritis affects people in different ways, and not everyone has pain. The most common symptoms are:

• Pain when you move, which often gets better with rest
• Stiffness, especially for the first 30 minutes after you get up from resting
• Swollen joints, especially after using the joint a lot
• Less movement in the joint than normal
• A joint that feels loose or unstable

What causes osteoarthritis?

Researchers aren't sure what causes osteoarthritis. They think that it could be caused by a combination of factors in the body and the environment. Your chance of developing osteoarthritis increases with age. They also know that some people are more likely to develop it than others.

Who is more likely to develop osteoarthritis?

Things that make you more likely to develop osteoarthritis include:

• Aging. Osteoarthritis can happen at any age, but the chance of getting it increases in middle-aged adults and older. After age 50, it is more common in women than in men.
• Being overweight. Extra weight puts more stress on your joints.
• Having a past injury or surgery on a joint. This is often the cause of osteoarthritis in younger adults.
• Doing a lot of activities that overuse the joint. This includes sports with a lot of jumping, twisting, running, or throwing.
• Having a joint that doesn't line up correctly.
• A family history of osteoarthritis. Some people inherit genetic changes that increase their chance of developing osteoarthritis.

How is osteoarthritis diagnosed?

There is no specific test for osteoarthritis. To find out if you have osteoarthritis, your provider:

• Will ask about your symptoms and medical history
• Will do a physical exam
• May use x-rays or other imaging tests to look at your joints
• May order lab tests to make sure that a different problem isn't causing your symptoms

What are the treatments for osteoarthritis?

The goal of treating osteoarthritis is to ease your pain, help you move better, and stop it from getting worse.

Treatment usually begins with:

• Exercises to improve strength, flexibility and balance
• Weight loss, if needed, to improve pain, especially in your hips or knees
• Braces or shoe inserts (orthotics) that a health care provider fits for you

You can buy some pain relievers and arthritis creams without a prescription. They can be helpful, but it's best to talk to your provider about using them. If they don't help enough, your provider may prescribe injections (shots) into the joint or prescription pain relievers.

Complementary therapies may help some people. Massage can increase blood flow and bring warmth to the area. Some research shows that acupuncture may help relieve osteoarthritis pain. Simple things like heat and ice can help, too.

If none of these treatments help enough, surgery may be an option. You and your provider can decide if it's right for you.

Rheumatoid arthritis (RA) is a form of arthritis that causes pain, swelling, stiffness and loss of function in your joints. It can affect any joint but is common in the wrist and fingers.

More women than men get rheumatoid arthritis. It often starts in middle age and is most common in older people. You might have the disease for only a short time, or symptoms might come and go. The severe form can last a lifetime.

Rheumatoid arthritis is different from osteoarthritis, the common arthritis that often comes with older age. RA can affect body parts besides joints, such as your eyes, mouth and lungs. RA is an autoimmune disease, which means the arthritis results from your immune system attacking your body's own tissues.

No one knows what causes rheumatoid arthritis. Genes, environment, and hormones might contribute. Treatments include medicine, lifestyle changes, and surgery. These can slow or stop joint damage and reduce pain and swelling.

Your shoulder joint is composed of three bones: the clavicle (collarbone), the scapula (shoulder blade), and the humerus (upper arm bone). Your shoulders are the most movable joints in your body. They can also be unstable because the ball of the upper arm is larger than the shoulder socket that holds it. To remain in a stable or normal position, the shoulder must be anchored by muscles, tendons, and ligaments.

Because your shoulder can be unstable, it can be easily injured. Common problems include

• Sprains and strains
• Dislocations
• Separations
• Tendinitis
• Bursitis
• Torn rotator cuffs
• Frozen shoulder
• Fractures
• Arthritis

Health care providers diagnose shoulder problems by using your medical history, a physical exam, and imaging tests.

Often, the first treatment for shoulder problems is RICE. This stands for Rest, Ice, Compression, and Elevation. Other treatments include exercise and medicines to reduce pain and swelling. If those don't work, you may need surgery.