Are you ready for what MRI stands for? It's magnetic resonance imaging (say: mag-NET-ik REZ-uh-nents IM-uh-jing). That's a mouthful, but MRI machines do a simple and important thing — they take detailed pictures of the inside of the body that help doctors learn exactly what's wrong when someone is having a problem.
Are you having an MRI? It won't hurt, but you do have to hold still!