How do i know if i broke my finger?

Need x-ray to know: Fractures that cause an obvious deformity are self evident. But many serious finger and joint fracture may not be obvious. You need an x-ray to be sure you don't have a fracture. The notion that if you can move it you don't have a fracture is not true. The so called "jammed" finger should be evaluated with an x-ray to rule out potential fractures.

Fracture?: Unless you have a marked deformity of the finger, you will need an x- ray to determine if you have a fracture. This will be accompanied by a physical exam of finger and medical history.