  We present the numerical solution of the one-loop QCD evolution equation for
the genuine twist-three part of the orbital angular momentum (OAM)
distributions of quarks and gluons inside a longitudinally polarized nucleon.
This is based on the observation that the evolution is identical to that of the
Efremov-Teryaev-Qiu-Sterman function for transverse single spin asymmetry.
Together with the known evolution of the Wandzura-Wilczek part, the one-loop
evolution of OAM distributions is now practically under control. We also study,
for the first time, the scale dependence of the potential angular momentum
defined as the difference between the Ji and Jaffe-Manohar definitions of OAM.
