Mallet finger is one of the most commonly undertreated hand injuries — not because it is complex, but because the window for non-surgical treatment closes quietly while people wait to see if it resolves on its own. It does not resolve on its own.

"If you can move it, it's not broken" is wrong. Movement tells you whether the tendons are working — not whether the bone is intact. Here's what actually tells the difference, and the mallet finger window you cannot afford to miss.