15 Facts About Your Bones and Skeletal System

Make no bones about it: Your skeletal system is a huge part of what helps keep your body at peak performance. But did you know that you lose bone density as you age? Or that your longest bone is in your thigh? What about the idea that your bones are living tissue?

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

We cover these fun facts about your skeletal system and more with orthopaedist Meredith Konya, MD.

15 facts about the skeletal system

1. Babies have more bones than adults

If you’re feeling a little hollow today, there’s a good reason. You’ve got 206 bones right now, but you were born with around 300.

“Babies have more bones than adults because your skeleton fuses together as you grow older,” says Dr. Konya. “That’s how you end up with a solid skull instead of soft spots between bones, called fontanelles.”

2. Babies aren’t born with traditional kneecaps

A baby’s knees are made of cartilage, which hardens over time. Kneecaps aren’t fully developed until around age 10 or 12.

3. More than half of your bones are in your hands and feet

Each hand has 27 bones, while each foot has 26. Together, that’s a total of 106 bones that allow you to run a race, kick a ball, give a high five and so much more.

4. You grow until your growth plates close

You have growth plates at the ends of the bones in your arms and legs. These plates are made of cartilage. They’re usually fully developed in the late teens for boys and within two years of a girl’s first menstrual cycle.

5. Bones are living tissue

The collagen in bone constantly replenishes itself. It’s also the most prominent protein in your entire body, making up about 30% of your body’s total protein. Bones repair themselves so quickly that you have a new skeleton about every seven years.

6. Your legs contain your longest bones

Your femur (thigh bone) is the upper leg bone that runs from your hip to your knee.

“It’s the longest and largest bone in your body because it’s responsible for supporting your entire body weight,” notes Dr. Konya.

And that’s no easy feat when you’re doing high-impact exercises, like burpees or jumping rope.

7. Your smallest bones are in your ears

The stapes is a stirrup-shaped bone in your middle ear that measures only 0.11 inches, making it the shortest bone in your body. It’s part of your ossicles, a three-bone structure in your middle ear responsible for sending sound from your outer ear to your inner ear. Without the stapes, you wouldn’t be able to hear.

8. Your funny bone isn’t a bone at all

You might find this humorous, but it’s true: Your upper arm bone is called the humerus. That’s what gives your “funny bone” its name. But in reality, anytime you bang your elbow on something, it’s the ulnar nerve that triggers that tingling, prickly pain.

9. Your joints hold everything together

Your joints are like the hinges on a door — they exist as a connection between two different bones. Some, like your knee joint, move a lot. Others, like the joints in your skull, don’t move at all. Muscles and ligaments support your joints, and cartilage helps cushion them. But when cartilage wears out, you develop arthritis in your joints.

10. You have a floating bone just below your lower jaw

There’s a crescent-shaped bone that anchors your tongue and helps you speak and swallow. It’s called the hyoid, and it’s not connected to any other bone. Instead, it’s held in place by ligaments, muscles and cartilage.

11. Your skeleton protects you in several ways

Your skeleton shields your brain, heart, lungs and other major organs from harm. But it also plays a vital role in your immune system:

Bone marrow, located in the spongy center of most of your bones, makes white and red blood cells.
White blood cells help protect you from infections.
Red blood cells help transport oxygen throughout your entire body.

So, your bones defend your body on many fronts — often without you even realizing it.

12. Your bones can be self-healing

Most broken bones can heal on their own (with proper medical attention). Blood vessels form in the area almost immediately after you break a bone to help the healing process begin. Within 21 days, collagen forms to harden and hold the broken pieces in place. The damaged surfaces knit together to form new bone.

To activate this bone superpower, it’s essential to seek medical care for a broken bone. Otherwise, it might not heal properly.

13. Men and women have different bone structures

Women tend to have a smaller skeletal system than men. They’re also at higher risk for low bone density and bone loss. But their pelvic bones are also wider to allow for the possibility of childbirth. As a fetus grows, a woman’s pelvis and hip bones shift to provide more space.

14. Tooth enamel is harder than your bones

Your teeth aren’t bones, but they’re mostly made up of the same materials, like calcium. Tooth enamel, the outer layer of your teeth, is the hardest substance in the human body. In fact, your enamel is so strong and durable that it’s resistant to decomposition after death. And as the bacteria that cause tooth decay no longer survive after you die, your teeth are left behind along with your bones.

15. Nutrition keeps your bones strong and healthy

Keep your bones healthy and strong by providing them with the nutrients they need. The trick is to get adequate amounts of calcium, vitamin A, vitamin K and vitamin D from the foods you eat as early in life as possible. Once you stop growing and begin to lose some bone density with age, these vitamins and minerals continue to strengthen your bones and keep them healthy.

“Your bones and your skeleton are truly amazing,” says Dr. Konya. “They grow, repair themselves and keep your entire body positioned as you move through life.”

That’s why it’s so important to do your best to keep your bones healthy.

“Eat well and exercise as often as you can so your bones can support you as long as you need them to,“ Dr. Konya encourages.