These BONE facts were brought to you by https://www.healthline.com/health/fun-facts-about-the-skeletal-system#3
Bones are filled with a spongy tissue
Bone marrow is a spongy substance that’s found inside large bones like your hips, pelvis, and femur. Bone marrow houses stem cells. Stem cells are responsible for producing many of your body’s most important cells, including blood, brain, heart, and bone cells.
The body has two types of bone
You may think of bone as a hard, dense material, but only one type of bone is like this. This dense, hard bone is called cortical bone. Cortical bones are primarily the “structure” bones.
The second type, trabecular bone, is soft and spongy. It’s often found inside large bones and in your pelvis, ribs, and skull. Though it’s less dense than cortical bone, it’s still quite hard and protective.
Bones are designed to take a beating
Yes, bones can break. But they’re designed to stand up to daily wear and tear. For example, some bones must be able to absorb two to three times your body weight in force. They must also be resilient. You take 1 to 3 million steps per year, so bones are built to take the constant use.
More than half your bones are in your hands and feet
You have 206 bones in total, and 106 of them are in your hands and feet.
One bone isn’t connected to any other bones
The hyoid bone, which is in your throat, is the only bone that doesn’t connect to a joint. The hyoid is responsible for holding your tongue in place.
Most people have 12 ribs, but some have 13
A 13th rib is rare — only 1 percent of people are born with it. In most people, this extra rib, called a cervical rib, can cause medical issues like neck pain. For that reason, people born with this extra rib often have it removed.
The biggest joint in your body is your knee
At the knee joint, three bones connect: your femur, tibia, and patella. Those three large bones require an equally large joint to connect them. That’s why your knee is the largest joint in your body.
A skeletal system isn’t that common in the world
Humans are part of a group of creatures called vertebrates. That means our bones are covered by a system of tissue and skin. Only 10 percent of the world’s animals (humans included) are vertebrates.
The other 90 percent are invertebrates. Their bones are on the outside of their body.
Bones are strong, but teeth are stronger
The enamel on your teeth, which are considered part of your skeletal system, is actually stronger than bones. Enamel protects the delicate nerves and tissue inside your teeth. Inch for inch, your teeth can take more wear and tear than any of your other bones.
Bones are natural healers
When you fracture a bone, your body will go to work producing new bone cells and helping heal the break. A cast or brace just ensures the bone heals straight so you don’t have more problems in the future.