Section 13J. (a) For the purposes of this section, the following words shall, unless the context indicates otherwise, have the following meanings:—

''Bodily injury'', substantial impairment of the physical condition including any burn, fracture of any bone, subdural hematoma, injury to any internal organ, any injury which occurs as the result of repeated harm to any bodily function or organ including human skin or any physical condition which substantially imperils a child's health or welfare.

''Child'', any person under fourteen years of age.

''Person having care and custody'', a parent, guardian, employee of a home or institution or any other person with equivalent supervision or care of a child, whether the supervision is temporary or permanent.

''Substantial bodily injury'', bodily injury which creates a permanent disfigurement, protracted loss or impairment of a function of a body member, limb or organ, or substantial risk of death.

(b) Whoever commits an assault and battery upon a child and by such assault and battery causes bodily injury shall be punished by imprisonment in the state prison for not more than five years or imprisonment in the house of correction for not more than two and one-half years.

Whoever commits an assault and battery upon a child and by such assault and battery causes substantial bodily injury shall be punished by imprisonment in the state prison for not more than fifteen years or imprisonment in the house of correction for not more than two and one-half years.

Whoever, having care and custody of a child, wantonly or recklessly permits bodily injury to such child or wantonly or recklessly permits another to commit an assault and battery upon such child, which assault and battery causes bodily injury, shall be punished by imprisonment for not more than two and one-half years in the house of correction.

Whoever, having care and custody of a child, wantonly or recklessly permits substantial bodily injury to such child or wantonly or recklessly permits another to commit an assault and battery upon such child, which assault and battery causes substantial bodily injury, shall be punished by imprisonment in the state prison for not more than five years, or by imprisonment in a jail or house of correction for not more than two and one-half years.