What is the definition or description of: subungual hematoma?

Blood beneath . . .: The nailbed. Trauma to the nailbed (as from an inadvertent hammer strike) can split the soft tissues of the nailbed, causing bleeding, but the collection of blood is prevented from escaping by the adherent nail to the remainder of the nailbed. Drilling or burning a hole can let the blood out, relieving pain, but repair of larger naibed lacerations is needed to prevent nail growth abnormalities.

Subungual Hematoma : This term refers to blood collection beneath a nail. It can involve finger or toenails and typically requires some form of trauma or injurious force.