  The mass spectrum of orbitally and radially excited states of B and D mesons
is calculated in the framework of the relativistic quark model. The expansion
in inverse powers of the heavy quark mass is carried out up to the first order,
while the light quark is treated without expansion. We find that the
relativistic treatment of the light quark plays an important role. Different
patterns of P level inversion are discussed. The obtained masses of orbitally
and radially excited states are in accord with available experimental data and
heavy quark symmetry relations.
