Radius (bone) facts for kids

The human arm

The radius is one of the two main bones found in your lower arm, between your elbow and your hand. It's a long bone that helps you move your wrist and hand in many ways. The other bone in your lower arm is called the ulna. These two bones work together to give your forearm strength and flexibility. You can feel your radius bone on the thumb side of your forearm.

The Radius Bone: Your Arm's Helper

The radius bone is super important for how your arm works every day. It's one of the main bones in the forearm of animals with four limbs, like humans, dogs, and cats. It connects your upper arm bone (the humerus) to your wrist and hand.

Where is the Radius Located?

The radius is on the "thumb side" of your forearm. If you hold your arm out with your palm facing forward, the radius is the bone on the outside. It runs from your elbow down to your wrist. At your elbow, it connects to the humerus, and at your wrist, it connects to the small bones of your hand.

What Does the Radius Do?

The radius has several important jobs:

• Movement: It helps you twist your forearm, allowing you to turn your palm up (like when you're asking for something) or down (like when you're pouring water). This movement is called pronation and supination.
• Support: It provides a strong framework for your forearm muscles to attach to. These muscles help you grip things, lift objects, and move your fingers.
• Connection: It forms joints at both ends. At the elbow, it forms part of the elbow joint, and at the wrist, it forms the main part of the wrist joint.

How the Radius Works with Other Bones

The radius doesn't work alone! It's part of a team of bones:

• The Ulna: This is the other bone in your forearm, located on the "pinky finger side." The radius and ulna run parallel to each other and connect at both the elbow and the wrist. They cross over each other when you twist your arm.
• The Humerus: This is your upper arm bone. The top of the radius bone, called the radial head, fits into a part of the humerus at your elbow, allowing for bending and straightening your arm.
• Wrist Bones: At the bottom, the radius connects directly to some of the small bones in your wrist, called carpals. This connection is key for all the movements your wrist can make.

Keeping Your Radius Healthy

Like all bones, the radius can sometimes get injured, especially if you fall on an outstretched hand. It's important to keep your bones strong by eating healthy foods rich in calcium and vitamin D, and by getting regular exercise. If you ever feel pain in your forearm after a fall, it's always a good idea to tell a grown-up so they can help you get it checked out.

Images for kids

• 

  Full front view of the right radius bone.

• 

  Full back view of the right radius bone.

• 

  Full view of the right radius bone from the inside.

• 

  Full view of the right radius bone from the outside.

• 

  An X-ray showing a small break in the top part of the radius bone near the elbow.

• 

  An illustration showing a break in the middle part of the radius bone.

See also

In Spanish: Radio (hueso) para niños