Genesis 32:32
←Back to VersesTherefore the children of Israel eat not of the sinew which shrank, which is upon the hollow of the thigh, unto this day: because he touched the hollow of Jacob’s thigh in the sinew that shrank.
So, the Israelites don't eat a specific part near the thigh's hollow until now. This is because someone once touched that spot on Jacob's shrunken thigh.
King James Version
Simple English
* Work in progress - there may be occasional inaccuracies