same thing as LFS I think. thumb sucking is one way of developing jaws stunted in horizontal growth, with no shortage of vertical growth.
thumb sucking like enlarged adenoids forces a person to assume their tongue in an unnatural inferior position. without the tongue in proper position, the upper palate isn't formed properly and the muscles around the mouth area are unopposed in their pressure against the maxilla, narrowing it over time, over erupting teeth, elongating the face
this is extreme thumb sucking, most thumb suckers seem to end up with easily correctable maloclussions