Negative commandment · Lo Ta’aseh #183 of 613
Not to eat the displaced [sciatic] nerve
שלא לאכול גיד הנשה
The verse · Bereshit 32:33
עַל־כֵּן לֹא־יֹאכְלוּ בְנֵי־יִשְׂרָאֵל אֶת־גִּיד הַנָּשֶׁה אֲשֶׁר עַל־כַּף הַיָּרֵךְ עַד הַיּוֹם הַזֶּה כִּי נָגַע בְּכַף־יֶרֶךְ יַעֲקֹב בְּגִיד הַנָּשֶׁה
“Therefore the children of Yisra᾽el eat not of the sinew of the vein, which is upon the hollow of the thigh, to this day: because he touched the hollow of Ya῾aqov’s thigh in the sinew of the vein.”
The Rambam’s words
Not to eat the displaced [sciatic] nerve as [Genesis 32:33] states: "Therefore, the children of Israel do not eat the displaced nerve."
שלא לאכול גיד הנשה, שנאמר "על כן לא יאכלו בני ישראל את גיד הנשה" (בראשית לב,לג).
Why · Sefer HaChinuch #3
Not to eat the sciatic nerve
“It is from the roots of this commandment [that it is to serve as] a hint to Israel that though they will suffer many troubles in the exile by the hand of the nations and by the hand of the [descendants] of Esav (i.e. the Christians), [the Jews] should trust that they will not perish, but rather that their descendants and name will stand firm forever, and that their redeemer will come and redeem them from their oppressor.”
Who & when
“And [it] is practiced in every place and at all times by males and by females.”
Where in the Mishneh Torah
Hilchot Forbidden Foods הלכות מאכלות אסורות