Trauma to the nail can cause the nail plate to be torn from the nail bed. Unlike other types of avulsion, when a nail is lost, it is not typically reattached. Following the loss of the nail, the nail bed forms a germinal layer which hardens as the cells acquire keratin and becomes a new nail.
2. a wound produced by the tearing of body tissue, as distinguished from a cut or incision. External lacerations may be small or large and may be caused in many ways, such as a blow from a blunt instrument, a fall against a rough surface, or an accident with machinery.