“Aggressive debridement” was recommended by the only good study I could find, and I paused on the word “debridement.” Both prefix and suffix pointed to a French origin. Free association fetched up “bride,” but that's a good Old English word, and although I could imagine “debridement” developing from that – divorce is not too far-fetched a metaphor for detaching dead or diseased tissue from living tissue – I didn't think it likely. Further association brought me to “debris,” which seemed far likelier, but I couldn't imagine the phonological history that would invent a 'd' out of thin air. At that point I resorted to the online etymological dictionary.
It turned out to have a Germanic root after all, but it's the root that gave us “bridle”: a word that French and English horse-people have shared since long before the Conquest. French débrider meant literally “to unbridle,” which is not a first very intuitive, but débrider eventually became the word for taking all the tack off a horse: at which point the imagery becomes quite exact and satisfying. Most horse tack is in fact dead tissue – leather – which you take off to the relief of the living flesh. To 18th and 19th Century surgeons, who were as familiar with saddle horses as we are with automobiles, the metaphor would have sprung easily to mind.
So I could go back to filing down that ugly toenail. The universe was intelligible, after all.