There are few more specific kashrut laws in the Torah than the prohibition known as the “gid ha’nasheh” (the sciatic nerve). The Torah states “. . . a man wrestled with him [Jacob] until the break of dawn. When he saw that he could not prevail against him, he touched the socket of his hip, and the socket of Jacob’s hip became dislocated as he wrestled with him. . . Therefore, the Children of Israel may not eat the gid ha’nasheh, which is on the socket of the hip, until this day, for he touched the socket of Jacob’s hip, in the gid ha’nasheh.” (Genesis 32:25-33).

For connoisseurs of the finer things in life, filet mignon is a food to be savored. And yet, for the kosher consumer, it is rare that one has the opportunity to enjoy such a steak. The part of the animal from which filet mignon is cut, the tenderloin, runs along the spine of the animal, close to its sciatic nerve. Since the sciatic nerve of any animal is prohibited, the meat must be carefully separated (a process referred to either as nikkur or treibor), an extremely difficult and delicate process. In America, there is a gezerah (rabbinic decree) not to process the gid ha’nasheh, but it is done in other parts of the world, such as Israel.

According to kabbalistic interpretations, the sciatic nerve is referred to as the gid ha’nasheh because nasheh is related to the Aramaic word for forgetting or becoming disconnected. Those who eat the gid ha’nasheh risk becoming disconnected from the ways of the Children of Israel.