or "by means of the wound"
Technically, there is no such thing as a "Family crest." That's just a phrase that family history agencies in America use to sell some crest that was owned by someone in the distant past. In most countries where many crests originated, such practice would be illegal. Coat's of Arms were not owned by families, but individuals, and a Coat of Arms was often passed down from father to son, and the son could make any changes he wanted to it to reflect his own values. And in reality, you could very well design your own crest to represent you and then pass down to your children.
Great point Paul. As I read down the posts, I was hoping someone would say that. I think it is even more significant that your own crest reflect personal accomplishments and demeanor rather than using an ancestor's (though there is nothing wrong with that and can be a point of pride depending on the ancestors)