The backrest of a vehicle seat having a headrest, which may be displaced from an in-use position to a safety position by the effect of a force generation device, and which is fixed, by means of retaining elements extending into the backrest. The retaining elements may be displaced relative to the backrest, under the effect of the force generating device, by means of at least one connector guide, from a connector into a connector side block. The connector slide block is preferably lockable in the connector on the displacement from the in-use position to the safety position. One embodiment includes a rectangular connector slide block which performs a turning movement on the displacement, as a result of which the radial extent of the above relative to the connector is increased thus locking the connector slide block in the connector with a positive or non-positive fit.