The present communication is devoted to the analysis of in-plane lattice spacing oscillations (IPLSOs) during two-dimensional (2D) epitaxial growth. The physical origin of these oscillations is the finite size of the strained islands that may relax at their edges. Owing to this possible elastic relaxation, when growth takes place by formation and spreading of 2D islands, the mean in-plane parameter oscillates from the parameter of partially relaxed islands towards the parameter of a continuous pseudomorphic layer. The purpose of this paper is to give a synthesis of both experimental and theoretical recent results about IPLSOs: (1) IPLSOs are recorded and analysed for some systems in order to extract pertinent physical parameters. (2) The use of point forces and a semi-dynamical diffraction approach allow us to quantify the role of these parameters. For example, we show that the amplitude of IPLSOs depends linearly on the misfit and roughly linearly on the nucleation density. (3) Thanks to this theoretical understanding we discuss the experimental results obtained for various metallic systems such as V/Fe(001), Mn/Fe(001), Ni/Fe(001), Co/Cu(001), Fe/Cu(001), Fe/Fe(001), V/V(001). (C) 2002 Elsevier Science B.V. All rights reserved.