A vehicle seat includes a foam body having a first region, a second region, a top surface, and a bottom surface, and a trench defined by and between the first and second regions. The trench includes at least one section including a narrow portion having a first width and extending downwardly into the trench from the top surface, and a base portion below the narrow portion having a second width greater than the first width. The vehicle seat further includes a trim attachment fixture disposed in the foam body below the trench, wherein the trim attachment fixture is configured to be secured to a trim cover by an attachment member disposed in the base portion.