  We investigate the quark Wigner distributions in a light-cone spectator
model. The Wigner distribution, as a quasi-distribution function, provides the
most general one-parton information in a hadron. Combining the polarization
configurations, unpolarized, longitudinal polarized or transversal polarized,
of the quark and the proton, we can define 16 independent Wigner distributions
at leading twist. We calculate all these Wigner distributions for the $u$ quark
and the $d$ quark respectively. In our calculation, both the scalar and the
axial-vector spectators are included, and the Melosh-Wigner rotation effects
for both the quark and the axial-vector spectator are taken into account. The
results provide us a very rich picture of the quark structure in the proton.
