  A parton picture of inclusive quasi-elastic electron-nucleus scattering,
where individual nucleons are treated as (non point-like) partons of the
nucleus, is presented. All the necessary target-mass corrections to asymptotic
scaling are evaluated and a new scaling variable is obtained. Recent inclusive
data from Jefferson Lab are analyzed and shown to scale in terms of the new
variable. The new approach allows to extract in a model-independent way the
nucleon light-cone momentum distribution in the nucleus.
