Section 62(5)(iii) in The Bihar Panchayat Election Rules, 2006
(iii)The reference in this rule to the left forefinger of a voter shall, in the case where the elector has his left forefinger missing, be deemed to be a reference to any other finger of his/her left hand and, in the case where all the fingers of his/her left hand are missing, deemed to be a reference to any extremity of his/her left or right arm as he possesses.