Skull symbolism is the attachment of symbolic meaning to the human skull. The most common symbolic use of the skull is as a representation of death and mortality, but has changed with modern times as in clothing most skulls are designed for fashion rather than the historical symbolism.
Humans can often recognize the buried fragments of an only partially revealed cranium even when other bones may look like shards of stone. The human brain has a specific region for recognizing faces,and is so attuned to finding them that it can see faces in a few dots and lines or punctuation marks; the human brain cannot separate the image of the human skull from the familiar human face. Because of this, both the death and the now past life of the skull are symbolized.
In Mexican tradition, the death is celebrated, specially with the day of the dead, were skull art gains it's full expression.