Later on, in the XIII Dynasty the tendency was the same one. Inscriptions on Egyptian coffins were also embellished with images. One of the best examples is the coffin of Khnum Nakht from Meir.

Coffin of Khnum Nakht from Meir. Head extreme with the image of Isis. On the left the false door with the two udyat eyes indicating the threshold between the earthly world and the Afterlife. XIII Dynasty. Metropolitan Museum of Art of New York.
There is a group of coffin from Thebes (from el-Asasif) dating back to the XIII Dynasty and whose main feature are their black background colour. They also include some figures: at the head end of the panel there is the false door and at both extremes of the coffin the artists draw the images of two goddesses with her raised arms.

Coffin of Ikhet from el-Asasif. XIII Dynasty. At the head end there is the false door and at the head extreme a feminine figure stands with raised arms. Photo: www.metmuseum.org

Coffin of Nefnefret from el-Asasif. XIII Dynasty At both extremes the two feminine images, Photo: www.metmuseum.org
These two women are not always identified, as for instance in the coffin of Ikhet or the one of Nefnefret, but in some cases the hieroglyphs accompanying them says clearly that they are Isis and Nephtys. This is what we can see in the coffin of Entemaemsaf. The woman on the head extreme is goddess Isis and the woman on the feet extreme is goddess Nephtys.

Coffin of Entemaemsaf. Isis at the head and Nephtys at the feet. XIII Dynasty. El-Asasif. Photo: Metropolitan Museum of Art of New York.
Model coffins are not an exception, because Egyptians treated them as authentic coffins. For instance the model coffin of Teti from the Second Intermediate Period is of unknown origin (maybe from Thebes, although it is not for certain), but it follows the feature indicated above. The coffin, with some spells from the Coffin Texts, has a false door in the head end of the right panel and at the head extreme a feminine figure is standing with her raised arms.

Model Coffin of Teti. Second Intermediate Period. British Museum. Photo: www.britishmuseum.org
In Ancient Egypt the decoration of coffins during the XI and XIII Dynasties could include hieroglyphs and images of these two women at both extremes. It seems reasonable to think that they were Isis at the head extreme and Nephtys at the feet extreme.
But, what happened during the XII Dynasty?…