Halakhah for Chullin 191:19
האוכל מגיד הנשה כזית סופג ארבעים אכלו ואין בו כזית חייב
Said Samuel to him, 'Be not alarmed, for he who taught you this taught you according to the view of R'Judah'.
Sefer HaChinukh
And [it] is practiced in every places and at all times by males and by females. And one who transgresses it and eats a [whole sciatic nerve], even if it is less than an olive's-worth - or eats a kazayit (the size of a large olive) from a large sciatic nerve - is lashed (see Chullin 96a).
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