Share 'Body parts+adjective requiring possessive adjective'

I know body parts are generally preceded by the definite article. But I've heard that when the body part is qualified by an adjective, this rule is flexible. Is it correct to say the definite article is always replaced by a possesive adjective when an adjective qualifies a body part?  Elle a haussé ses lourdes epaules  I've heard "droite" and "gauche" may be exceptions to the above rule but…