A<unk>  is a collection of blood (hematoma) underneath a toenail or fingernail which often results from a traumatic injury such as slamming a finger in a door. A laceration of the nail bed causes bleeding into the constricted area underneath the hard nail plate. Because the blood disrupts the connections between the nail bed and nail plate, throbbing pain is common. The nail develops a black discoloration overlying the laceration.
Subungual hematoma
Dens evaginatus
Pediculus capitis
Cephalhematoma
Subgaleal hemorrhage
Naevus Lipomatosus superficialis
Pediculosis capitis
Trichostasis spinulosa