A subungual hematoma is a collection of blood that forms under the nail due to a tear in the nail bed. This type of hematoma most commonly occurs after an impact injury to the finger or toe, such as when stubbing a toe or jamming a finger. Immediately after the injury, the nail may look normal but within hours the blood accumulates under the nail, causing it to lift up and become discolored and swollen. The collection of blood causes severe pain. #smashedfinger #injury #diy #howthingswork #homer