  The ionized gas kinematics of the Virgo Cluster galaxy NGC 4254 (Messier 99)
is analyzed by an harmonic decomposition of the velocity field into Fourier
coefficients. The aims of this study are to measure the kinematical asymmetries
of Virgo cluster galaxies and to connect them to the environment. The analysis
reveals significant $m=1,2,4$ terms which origins are discussed.
