  The spin-orbit splitting in heavy-light mesons is seen to be suppressed
experimentally. It is shown that it can be understood qualitatively in the
frame work of Dirac theory. An alternative derivation of a relativistic
dynamical symmetry for the Dirac Hamiltonian, which suppresses spin orbit
splitting, is also given. However it is shown that such a symmetry is not
needed since the spin-orbit splitting in Dirac theory with Coulomb like
potential (as is the case for the one gluon exchange potential in pQCD) is
small anyway.
