musculoskeletal system library

Bones and muscles -- the musculoskeletal system -- are what make the body move. Learn how every movement of the body is the result of the coordination of bones, muscles, tendons, and ligaments.

Featured Article: How Muscles Work

Muscles are one of those things that most of us take completely for granted, but they're the body's engine. Without our muscles, we couldn't walk or talk -- and our blood would stop flowing. See more »

Articles 1-9 of 9

Can you really be double-jointed?

Can you do creepy, bendy things with your fingers that freak out your friends? You might have been called double-jointed. What's really going on with those joints of yours?

Do babies have kneecaps?

Babies have adorable smiles and teeny tiny fingers, but there's a persistent rumor that these new, tiny humans don't have kneecaps. What's the story of a baby's bones?

How Bones Work

If you didn't have bones, you'd be puddled on the floor like a jellyfish with skin -- and your ability to impress people on the dancefloor would be severely compromised. What else are skeletons for, besides decorating your house for Halloween?

How does the spine form?

In a way, your spine is the keystone that holds your body together. Since it has so many important jobs, it has to develop in exactly the right way. How does this happen?

How Muscles Work

Muscles are one of those things that most of us take completely for granted, but they're the body's engine. Without our muscles, we couldn't walk or talk -- and our blood would stop flowing.

What makes your knuckles pop?

If you've ever laced your fingers together, turned your palms away from you, bent your fingers back and heard a loud crack or pop, you know what knuckle-popping sounds like. So, what would happen if you popped your knuckles all the time?

Muscle Types Animation

Muscles perform four essential functions: They maintain body posture stabilize joints produce movement and generate heat we need to survive. This animation illustrates what different muscles do and how muscles work together.

Skeletal Muscle

Have you ever wondered exactly how muscles contract? This animation shows the contraction of a skeletal muscle up close.

Skeletal System Components

An adult skeleton supports the entire body and protects its internal organs. This animation takes you on a tour of the various components that make up the skeletal system.