Gid hanasheh
Gid hanasheh (Hebrew: גִּיד הַנָּשֶׁה) is the term for sciatic nerve in Judaism. It may not be eaten by Jews according to Halacha (Jewish Law). The laws of prohibition regarding the gid hanasheh are found in Masechet Chullin (Hullin) Perek 7.
Source
The Torah (Genesis 32) recounts that Jacob fought with an angel (according to Rashi this was Esau's guardian angel) who could not beat him. At the end of the fight, the angel moves a nerve in Jacob's leg causing him to limp. The verse then states: "Therefore the children of Israel (Jacob) do not eat the gid hanasheh until today."
Removal
The removal of the gid hanasheh and chelev (other forbidden fats) is called nikkur. Since it is labor intensive to remove all the forbidden parts of the hindquarters of an animal, the entire hindquarters are usually sold to the non-kosher market outside of Israel and a few other markets with sufficient Jewish populations to justify the expense.
See also
- Sciatic nerve — non-Hebrew terminology