The easiest way to "see" the difference for reference only...a bruise is a bruise is a bruise.. however, truly one is created by trauma while the other is not. think of the ecf patient who falls frequently (those are bruises) now think of the ecf patient who is bedridden but seems to have "bruises" that is just the pooling effect of the blood creating the purple, blue, yellow, black spots. this is ecchymosis. However, you mentioned scratches being visible as well to the area of the bruising...therefore that is the trauma, it was not created naturally but through scratching...therefor BRUISING.. so...you are the smart one :)