By about 1835, the flat wooden busk that was worn in the earlier Regency corsets to lift and separate the breasts became broad and was supplemented along the sides and in the center back to support lacing with whalebones.
(Extant corsets: 1827 and 1832 show the wide wood busk down the center with reinforcements alongside of it. Earlier busks were tapered and narrow to accommodate the higher waist. As the 30’s progressed and the silhouette lengthened, so did the overall shape and the busk).