  The general spin structure of the relativistic nucleon wave function in the
$3q$-model is found. It contains 16 spin components, in contrast to 8 ones
known previously, since in a many-body system the parity conservation does not
reduce the number of the components. The explicitly covariant form of the wave
function automatically takes into account the relativistic spin rotations,
without introducing any Melosh rotation matrices. It also reduces the
calculations to the standard routine of the Dirac matrices and of the trace
techniques. In examples of the proton magnetic moment and of the axial nucleon
form factor, with a particular wave function, we reproduce the results of the
standard approach. Calculations beyond the standard assumptions give different
results.
