The influence of the transverse forces that a fluid exerts on a suspended particle is investigated in the range of relative motion Reynolds numbers lower than 1000, which are encountered in dispersed two-phase flows. In the case of gas-particle flows, the density ratio is high enough for the unsteady terms (added mass, displaced mass and historical terms) to be neglected. In such conditions, useful expressions of the force (drag and lift) and the torque exerted by the gas on a spherical particle are reviewed, and some recent results are pointed out. The following cases are examined : translation in uniform or non-uniform flow, influence of particle rotation and proximity of the wall. Examples of computed particle trajectories are given, showing the influence of transverse forces. Emphasis is placed on the care which must be taken in applying certain theoretical or empirical results, and on the existing gaps which demonstrate the need for further research in this field.