Bend Me, Shape Me — Joints At Work

A gymnast raises her arm and takes a deep breath. She takes off running. Her feet pound the floor before her knees flex, jumping onto a springboard. She flies through the air. Her wrists bend as she hits the vault. Pushing hard, her shoulders shrug. Her hips bring her legs to her chest. She points her toes. She lands. Her ankles and knees bend once more. She raises her arms, cheering that she stuck the landing. Twisting, bending, she has made a perfect tumble — all thanks to her joints.

You know that your body can move in many different ways and hopefully, by now, that your bones can’t bend! It’s your joints, where two or more bones come together, that do most of the work. Your head is the only place in your body where joints don’t move. For the rest of your body, joints help you do everything from brush your teeth to sticking a complicated landing.

Sounds straightforward, right? But what you might not know is that your joints have different parts that help them work. Ligaments are stretchy material that connect bones to other bones. Have you ever used a rubber band to keep a set of items together? Ligaments keep joints together, just like rubber bands. When you move, your muscles pull on bones. Then the joint turns in the way it needs to. Both synovial (say sih-NO-vee-uhl) fluid, a thick liquid that acts as a cushion between your joints and cartilage (say CAR-till-edge), a strong flexible tissue material, make it easier for bones to slide past one another.

There are many different types of joints in the body, and a gymnast uses each kind!

When the gymnast begins to sprint down the runway, she bends her knees and her elbows. These are both hinge joints. They work just like a door swinging open and closed.

When she lands with her hands on the vault, her wrists have bent. The joints where the two bones of your lower arm meet are called condyloid (say CON-duh-loyd) joints. This type of joint allows your wrist to make a circular motion along with swinging like a hinge joint.

The gymnast then pushes off the vault and tucks her legs up to her chest. Both her shoulder and hip joints are called ball-and-socket joints. These joints allow for motion in any direction.

She lands and triumphantly straightens her back. The bones making up her spine are called vertebrae (say VER-tuh-bray). These move against each other when she bends and straightens her back. This is an example of gliding joints.

With her hands raised high in a salute, her thumbs are pressed against her other fingers. The thumb joint is an example of a saddle joint. This joint lets her thumb cross over her palm and back.

The gymnast looks from the judges to her coach and team. They’re all cheering her on! When she turned her head, she used a pivot joint at the very top of her neck. Pivot joints allow rotation.

These six types of joints give us the ability to move any way we need. Unfortunately, sometimes joints get hurt.

Have you ever had a sprain? This happens when one or more ligaments are stretched too far. You might get better by following the acronym RICE: Rest, Ice, Compression, Elevation. You might also wear a brace. This will keep your joint from moving. Then the ligaments will have time to heal.

Another type of joint injury is called arthritis (say arth-RYE-tis). One type of arthritis happens when cartilage is worn away through disease or over-use. Cartilage is a thin, very slippery material. When it disappears, bone rubs against bone. This is painful and makes movement difficult. There is no way to replace cartilage. Medication can help to ease pain. Sometimes surgeons will replace an entire joint with an artificial one. This often happens with older people who need hip joint or knee joint replacements.

Old or young, joints let every person move.