Sesamoid bone

What Is a Sesamoid Bone?

A sesamoid bone is a tiny, special bone found inside a tendon or muscle. These small bones are named after the word for "sesame seed" because many look like little seeds. The biggest sesamoid bone in our body is the patella, which is our kneecap.

Where Can We Find Sesamoid Bones?

You can find sesamoid bones in many places in your body. Here are a few spots:

• In the knee—the patella is the largest sesamoid bone and sits inside the quadriceps tendon.
• In the hand—two sesamoid bones are often found near the base of the thumb, inside tendons.
• In the wrist—the pisiform is a sesamoid bone inside a tendon.
• In the foot—usually, there are two sesamoid bones near the big toe, inside a tendon that helps you bend your toe.

Why Are Sesamoid Bones Important?

Sesamoid bones help tendons move smoothly. They act like pulleys, making it easier for muscles to pull on bones and help us move. This helps our muscles work better, letting us jump, run, and bend with less effort. Without these small but important bones, our movements would not be as smooth or strong.