עבודה זרה י, ב
דההוא קיסרא דהוה סני ליהודאי אמר להו לחשיבי דמלכותא מי שעלה לו נימא ברגלו יקטענה ויחיה או יניחנה ויצטער אמרו לו יקטענה ויחיה
There was a certain Roman emperor who hated the Jews. He said to the important members of the kingdom: If one had a nima rise on his foot, should he cut it off and live, or leave it and suffer? They said to him: He should cut it off and live.
Just what is a Nima?
Rashi understands that nima means dead flesh: בשר מת ומצערו Dead flesh that pains him. The Schottenstein Talmud follows Rashi and translates it as dead flesh.
The Koren English translation has this note on the word nima:
From the Greek νομή, nomē, meaning an expanding wound or gangrene. Another version of the text has nomi, matching the version of the word in other places.
Liddel and Scott's Greek-English Lexicon gives some more details. Among its many meanings νομή, means spreading, as in spreading baldness or spreading ulcers. Goldschmidt's German translation (the first translation of the entire Babylonian Talmud, published 1897-1935) translates nima as Geschwür, meaning ulcer. The Soncino English translation, which often follows Goldschmidt, also translates nima as an ulcer.
But while nima is translated either as gangrene or an ulcer, the two are most certainly not the same.
Ulcers describe a breakdown in the skin (or mucous membranes that line your mouth and gut) in which there is inflammation and in which dead tissues slough off. You may have had a mouth sore, which is a kind of ulcer. Other commonly seen ulcers are pressure sores (typically at the base of the spine and buttocks in bed-ridden patients) and ulcers that form on the feet of those with diabetes. The mainstay of treatment is to eliminate any pressure on the ulcer, to keep it meticulously clean, and to remove any dead tissue, a process known as debridement. Surgery is sometimes needed (for example, in cases of ulcerative colitis, in which ulcers form in the colon and rectum,) but in most cases can be avoided.
Gangrene is the death of tissue, caused by a loss of the blood flow. It is far less common than ulcers, and far more serious. (You can see all kinds of pictures of gangrene here.) It is mostly seen on the feet, but I've seen gangrene of the hands and fingers as well. When mountain climbers (and the homeless) loose fingers and toes, it's from gangrene.
There are two kinds of gangrene. In wet gangrene, bacteria invade tissue which have little or no blood supply. They feed on the tissue and produce a great deal of pus; hence the description "wet". Left untreated, the patient will likely become septic and die. Amputation is often the only treatment option. Dry gangrene has a slower onset, and the tissue looks mummified or cracked; hence the term "dry". It does not usually cause infection or death. After several days, it becomes obvious where the black dead tissue ends and the pink health tissue begins. At that time, the tissue can be amputated; commonly, it just falls off (like here, but don't look if you are eating).
From the context of our passage, it is not possible to be certain which of the two conditions is described in the word nima.The Jew-hating Roman Emperor was advised to amputate a foot with a nima on it. Since we don't treat ulcers with amputation, this lends support to those in the nima is gangrene camp: Rashi, Koren and Schottenstein. But perhaps, back in Talmudic days, foot ulcers were amputated. This would support those in the nima is an ulcer camp: Golschmidt and the Soncino. Either way, the description of the Jewish people as a nima really hurts. Just like the nima did.