Bone Up on Your Joints

Your knees get the prize for largest joints. They're also the most complex joints in your body. Three bones -- your thighbone, your shinbone, and your kneecap -- meet to form them. They’re held together by strong ropes called ligaments.

Noisy knees? Fingers that crack or pop? You may not need to excuse yourself, but that racket you're making may be your joints letting out gas. It escapes from liquid that helps keep your joints moving. But more serious things can make your joints sound off, too. Make sure to call a doctor if your noisy joints hurt and are swollen.

You couldn’t swing a tennis racket, run a mile, or even eat a slice of pizza without your joints. But not all of them help you do things. The joints in your skull are fixed in place to protect your brain. The same kind of joints holds your teeth in your jawbone.  

If you can bend, twist, or fold your fingers or arms in odd ways, you may be double-jointed. You have the same number of joints as everyone else, but yours are just more flexible. This tends to run in families and can come in handy if you’re a gymnast, ballet dancer, or musician. Sometimes having very loose joints can be a sign of a medical condition, so talk to your doctor about it, especially if it is causing you trouble.

Joints connect the bones in your back, arms, legs, jaw, and other places. Some, like those in your hips and shoulders, are ball and socket joints: A round end of bone fits into a small, cup-shaped area of another bone.  This type of joint gives you the greatest range of motion.

Your front door only opens one way, right? That's because it’s on a hinge. Your elbow and knee joints work the same way. You have lots of smaller hinge joints in your fingers and toes.

Don't take offense, but you couldn’t get your nose out of joint if you tried. It has no joints. No one really knows for sure how this expression came about, but it’s been around since the 1500s.

Surgery to replace knees, hips, and shoulders is common. In the 1970s, when knee replacement surgeries were first being done, doctors thought the new joints would last about 10 years. Now, most people get 20 years out of them. The new knee joints are made of titanium, stainless steel, and other materials. Doctors sometimes use cement to attach them to the bone.

Show your joints some love. You can get a great workout and burn off breakfast with a swim or a bike ride. These activities are easier on your joints than pounding exercises like running, kickboxing, and step aerobics.