A laceration is a tear, cut, or gash. Your heart can also get a more figurative laceration when you see your love kissing another. Either way, ouch.
A laceration implies that there is a tearing or jaggedness to the wound. A surgeon would not make a laceration on a patient, but an incision. Lacerations are reserved for things like barbed wire, errant nails, and fickle loves.