What is the difference between an mri and an x-ray?

Differences: Mri uses very strong magnetism to orient the body's water molecules to help see internal structures such as ligaments, joints, brain, etc. X-ray is the use of x-rays that pass through the body and develop a picture on film or a computer to see some structures such as bones, lungs, etc.

Both show anatomy: Both x-rays (radiographs) and MRI show anatomy. Radiographs do this by imaging differences in density, with all structures overlapping each other like a shadow. Mri looks at differences in the number hydrogen atoms in a region (proton density) and the local environment they are in. Mri is better for looking at soft tissues. Radiographs are better for looking at cortical bone.