Studies of flexural motions of lithosphere commonly apply a differential equation based on the thin-plate approach. In this approximation, the flexural response to a changing horizontal inplane force depends only on the curvature of the midplane of the thin-plate representing the mechanical behaviour of the lithosphere. However, in cases where an abrupt change of the geometry of the lithosphere occurs the midplane of the thin-plate is offset. We demonstrate that the combination of the offset with an inplane horizontal force produces an additional, rheology independent moment at the position of the geometry change. This effect has been overlooked by,previous studies of lithosphere deflections, and thin-plate problems in general. In the presented analysis, the thin-plate with an abrupt change in plate geometry represents lithopshere with a mechanically healed, inactive fault. However, the derived analytical solutions are,general and can be used to study problems with similar abrupt geometry changes.