The seventh perek (=chapter) of Masechet Hullin, which began on yesterday’s daf (=page) is called Perek Gid HaNasheh. The gid ha-nasheh is the sciatic nerve of the animal – nervus ischiadicus – which is forbidden to eat. This prohibition is unique among the commandments, inasmuch as it is not presented by the Torah as a teaching that Moses passed on to the Jewish People, rather it appears as part of the Biblical narrative in a story (see Bereishit 32:33) that takes place prior to the giving of the Torah at Mount Sinai. Following his wrestling with the angel, Ya’akov limps back towards his camp and the Torah concludes “Therefore the children of Israel eat not the sinew of the thigh-vein which is upon the hollow of the thigh, unto this day; because he touched the hollow of Jacob’s thigh, even in the sinew of the thigh-vein.”
This unique presentation leads to a number of questions about this mitzvah, among them –
- Does the prohibition to eat the sciatic nerve apply to all animals or only to some?
- Does it apply to sanctified animals as well as ordinary ones?
- Is the prohibition in force in both Israel and the Diaspora?
- Are both sciatic nerves forbidden, or is only one side prohibited, as would seem logical based on the source of the story?
The Gemara on today’s daf takes up this last question. While the Mishnah states clearly that each of the sciatic nerves is forbidden – both on the right and on the left – the Gemara teaches that Rabbi Yehudah disagrees, ruling that only a single one of the sciatic nerves is forbidden, and arguing that logic suggests that it is the sciatic nerve on the right side that is forbidden.
Rabbi Yehudah’s ruling notwithstanding, the accepted ruling is that both sciatic nerves are forbidden; although there are methods of removing the sciatic nerve and rendering hind-quarters of an animal kosher, the process is labor intensive and today it is difficult to find certain cuts of meat prepared for the kosher consumer. For details see –http://oukosher.org/index.php/common/article/whats_the_truth_about_inikkur_achoraim_i/