This obstetrical wax model shows a birth with the fetus in face presentation. By comparison with the terracotta model XVIII.26, the face is already in the vulva and the chin has rotated under the pubis. The rotation is diagnosed by measuring the relative positions of the nose, mouth, and chin, in order to ensure that all three are oriented toward the antero-posterior diameter of the inferior strait.

The model was commissioned by Felice Fontana, who was working on the installation of the Museo di Fisica e Storia Naturale of Florence, from the sculptor Giuseppe Ferrini and his assistant Clemente Susini.