International audienceThe N=28 shell closure is the first arising from the strong spin-orbit interaction. Therefore, the study of its evolution in nuclei with large neutron to proton excesses is intimately connected to the evolution of the spin-orbit interaction. From the doubly magic 48Ca nucleus to the close to drip line 42Si nucleus, a wealth of nuclear structure modifications is occurring, starting from spherical, prolate-spherical co-existence to oblate shapes. Using up to date experimental data along the N=28 isotonic chain, the underlying physics origin for these structural modifications will be emphasized. Among these, the action of tensor forces and the central density dependence of the spin-orbit interaction will be invoked
