  We study the Wigner functions of the nucleon which provide multidimensional
images of the quark distributions in phase space and combine in a single
picture all the information contained in the generalized parton distributions
(GPDs) and the transverse-momentum dependent parton distributions (TMDs). In
particular, we present results for the distribution of unpolarized quarks in a
longitudinally polarized nucleon obtained in a light-cone constituent quark
model. Treating the Wigner distribution as it was a classical distribution, we
obtain the quark orbital angular momentum and compare it with alternative
definitions given in terms of the GPDs and the TMDs.
