Information on this page is mapped to national science and health education standards and is for students in grades 4 through 6 who are learning about the human body. Teachers may also use these resources to inform their lesson plans.
On This Page
- For Students: Find all classroom materials and activities about joints
- Kahoot! Quiz: Test your knowledge about joints on your own or as a class!
- Vocabulary: See all of the medical terms in this lesson defined
- Teacher's Corner: See the National Education Standards covered in these lessons
For Students
What do joints do? Joints connect the bones in your body. On this page, you can learn about joints, what happens when they get hurt, and how to keep them healthy.
What are joints?
A joint is where two or more bones connect. Since bones don’t bend, without joints, it would be impossible for you to move around! The different types of joints are based on how much they can move.
- Freely movable, or synovial (suh-NOW-vee-uhl), joints can move a lot and are the most common joints in the body. Your elbows and hips are two examples of this type of joint.
- Partially movable, or cartilaginous (kaar-tuh-LA-juh-nuhs), joints can move a little. These are found in your spine and give it some flexibility.
- Immovable, or fibrous (FAI-bruhs), joints don’t move. For example, the bones in your skull were once flexible when you were born but have since fused (or joined) together to prevent movement.
What are joints made of?
Many types of tissue work together to form a movable joint. These tissues include:
- Bones, which come together at the joint.
- Ligaments (LI-guh-muhnts), which connect bones together.
- Tendons (TEN-dnz), which attach muscles to bones and control movement of the joint.
- Cartilage (KAAR-tuh-luhj), which covers the surface of a bone at a joint and reduces friction. Friction happens when bones rub against each other, which can wear bones down and cause pain.
- Bursae (BUR-say), which are fluid-filled pods within the joint that help cushion bones where they meet.
- Synovial membrane, which lines the joint, seals it into a capsule, and produces synovial fluid to lubricate the joint.
How do joints move?
Joints that move can do so in a few different ways. For example:
- Hinge joints like elbows and knees only allow movement in one direction.
- Pivot joints like the one in your neck allow rotating or twisting motion.
- Ball-and-socket joints like your shoulders and hips allow movement in many directions.
Try this!
Make a fist with one hand and cup it with the other hand. Move your fist around while keeping it within the grasp of your other hand. This is how ball-and-socket joints work!
- Condyloid (KON-dl-oyd) joints like your jaw consist of an egg-shaped bone that can move back and forth and side to side within an egg-shaped cavity in another bone.
- Saddle joints like the one at the base of your thumb allow movement back and forth and side to side, but do not allow rotation.
- Gliding joints like the ones in your wrists and ankles are made of two bones that slide past each other.
What happens when joints get hurt?
Sprains
Sprains happen when the ligaments in your joint stretch or tear. The most common place for a sprain is the ankle.
Most of the time, simple actions like resting and putting ice on the sprain at home are enough to help the sprain heal. People with really serious sprains may need surgery.
Dislocation
Dislocation means that one of your joints was knocked or pushed out of place.
If this happens to you, don’t try to pop your joint back into place on your own. Only a doctor or other health care provider should do this. Most people feel better as soon as the joint is back in place.
Arthritis
Arthritis (aar-THRAI-tuhs) is a group of diseases that cause damage to joints leading to swelling, stiffness, and pain. There are several different types of arthritis.
- Juvenile Idiopathic arthritis (JOO-vuh-nile i-dee-uh-PA-thuhk aar-THRAI-tuhs). The most common type of arthritis in children is called juvenile idiopathic arthritis (JIA). There are several types of JIA, many of which are autoimmune (aa-tow-uh-MYOON) in nature. In autoimmune diseases, the body mistakenly attacks its own cells and tissues. Taking specific medicines and having a healthy lifestyle can help kids with JIA feel better.
- Rheumatoid (ROO-muh-toyd) arthritis (RA). Another type of arthritis that is similar to JIA is called rheumatoid (ROO-muh-toyd) arthritis (RA). RA is an autoimmune disease, which mostly affects adults. In RA, the immune system attacks healthy joint cells, causing swelling and pain.
- Osteoarthritis (aa-stee-ow-aar-THRAI-tuhs). Sometimes, placing repeated stress on a joint, getting injured, or being overweight can put extra stress on the joint and cause the cartilage to become damaged. This type of arthritis is generally called osteoarthritis (aa-stee-ow-aar-THRAI-tuhs), which is more common as people age.
Arthritis can affect old or young people, but keeping your joints healthy as a young person may help reduce your risk of getting osteoarthritis.
How can I help keep my joints healthy?
Avoid joint injuries.
- Stretch and warm up before playing sports or working out.
- Wear the right protective equipment and shoes to support and protect your joints.
- Cool down and stretch after physical activity.
- Give your body time to rest and recover after intense activity.
Exercise.
Being physically active is one of the most important things you can do to keep your joints healthy. Regular activity helps keep the muscles around your joints strong and working the way they should.
Children and teenagers should get 60 minutes or more of physical activity each day. That may sound like a lot, but there are so many ways to be active!
Explore
Check out these videos to see how kids can find ways to move throughout the day.
Eat a balanced and healthy diet and maintain a healthy weight. Being healthy puts less stress on your joints and reduces wear and tear.
Go to the doctor regularly for check-ups.
Ask your doctor any questions you have about your joints. If you think something could be wrong, ask a parent, caregiver, or other trusted adult for help to schedule a doctor’s appointment.
Test your knowledge about joints with this Kahoot! quiz
This Kahoot! quiz tests your knowledge about joints and how to keep them healthy.
Vocabulary
Arthritis (aar-THRAI-tuhs). A group of diseases that cause damage to joints, leading to swelling, stiffness, and pain.
Autoimmune (aa-tow-uh-MYOON) disease. A type of disease where the body’s immune system mistakenly attacks its own healthy cells.
Ball-and-socket joint. Joints that allow movement in many directions. Examples: Shoulders and hips.
Bones. The tissues that make up your skeleton. Bones help you move, protect your organs, and even store energy and minerals. Learn more about bones.
Bursae (BUR-say). Fluid-filled pods within the joint that help cushion the friction.
Cartilage (KAAR-tuh-luhj). Tissue that covers the surface of a bone at the joint and reduces friction.
Condyloid (KON-dl-oyd) joint. Joints made of an egg-shaped bone that can move back and forth and from side to side within a cavity of another bone. Example: Jaw.
Dislocation. An injury that happens when a joint is knocked or pushed out of place.
Freely movable or synovial (suh-NOW-vee-uhl) joint. Joints with a big range of motion, like elbows and hips.
Gliding joint: Joints made of two bones that slide past each other. Examples: Wrists and ankles.
Hinge joint. Joints that only allow movement in one direction. Examples: Knees and elbows.
Immovable or fibrous (FAI-bruhs) joint. Joints that do not move, like joints between bones in your skull that were once flexible but have since fused together.
Juvenile Idiopathic arthritis (JOO-vuh-nile i-dee-uh-PA-thuhk aar-THRAI-tuhs). The most common type of arthritis found in children.
Ligaments (LI-guh-muhnts). Tissues that connect bones together.
Membrane. A thin sheet of tissue that acts as a boundary or lining.
Osteoarthritis (aa-stee-ow-aar-THRAI-tuhs). A type of arthritis caused by using a joint too much, getting injured, or being overweight that damages the cartilage.
Partially movable or cartilaginous (kaar-tuh-LA-juh-nuhs) joint. Joints that can move around a little, like the joints in your spine that give it some flexibility.
Pivot joint. Joints that allow a rotating or twisting motion. Example: Neck joints.
Rheumatoid (ROO-muh-toyd) arthritis. A type of arthritis where the immune system attacks healthy joint cells, causing swelling and pain.
Saddle joint. Joints that allow movement back and forth and side to side, but not rotation. Example: Joint at the base of the thumb.
Sprain. An injury that happens when ligaments in a joint stretch or tear.
Synovial fluid. A fluid produced by the synovial membrane that helps lubricate the joint.
Synovial membrane. A membrane that lines the joint, seals it into a capsule, and produces fluid to lubricate the joint.
Tendons (TEN-dnz). Tissues that attach muscles to bones and control movement of the joint.
Tissue. A group of cells working together to accomplish a specific job, like movement.
Teacher’s Corner
The content on this NIAMS webpage aligns with the following national standards:
Next Generation Science Standards
- NGSS Standard 4-LS1-1 “Animals have internal and external structures that serve various functions in growth, survival, behavior, and reproduction.”
- NGSS MS-LS1-1 “All living things are made up of cells, which are the smallest units that can be said to be alive. An organism may consist of one single cell (unicellular) or many different numbers and types of cells (multicellular).”
- NGSS MS-LS1-3 “In multicellular organisms, the body is a system of multiple interacting subsystems. These subsystems are groups of cells that work together to form tissues and organs that are specialized for particular body functions.”
National Health Education Standards
- NHES 1.5.1 “Describe the relationship between healthy behaviors and personal health.”
- NHES 1.5.4 “Describe ways to prevent common childhood/adolescent injuries and health problems.”
- NHES 1.5.5 “Describe when it is important to seek health care.”
CDC Healthy Schools
- CDC Characteristics of an Effective Health Education Curriculum, Characteristic 4: “Address social pressures and influences”