26 C.F.R. § 1.105-3
Section 105(c) provides an exclusion from gross income with respect to the amounts referred to in section 105(a) to the extent that such amounts (a) constitute payments for the permanent loss or permanent loss of use of a member or function of the body, or the permanent disfigurement, of the taxpayer, his spouse, or a dependent (as defined in section 152), and (b) are computed with reference to the nature of the injury without regard to the period the employee is absent from work. Loss of use or disfigurement shall be considered permanent when it may reasonably be expected to continue for the life of the individual. For purposes of section 105(c), loss or loss of use of a member or function of the body includes the loss or loss of use of an appendage of the body, the loss of an eye, the loss of substantially all of the vision of an eye, and the loss of substantially all of the hearing in one or both ears. The term "disfigurement" shall be given a reasonable interpretation in the light of all the particular facts and circumstances. Section 105(c) does not apply if the amount of the benefits is determined by reference to the period the employee is absent from work. For example, if an employee is absent from work as a result of the loss of an arm, and under the accident and health plan established by his employer, he is to receive $125 a week so long as he is absent from work for a period not in excess of 52 weeks, section 105(c) is not applicable to such payments. See, however, section 105(d) and § 1.105-4 . However, for purposes of section 105(c), it is immaterial whether an amount is paid in a lump sum or in installments. Section 105(c) does not apply to amounts which are treated as workmen's compensation under paragraph (b) of § 1.104-1 , or to amounts paid by reason of the death of the employee (see section 101).
26 C.F.R. §1.105-3