which muscle causes dimples
Dimples are especially common in the face, because the muscles pull the skin on the face around, instead of just pulling around bones. The face also has bits of body fat, which cause the dimples to be more visible. Most cheek dimples are the result of a shortened muscle, zygomaticus major, pulling on the skin. There are dimples in the chin and the elbows, as well. At rest, it's not noticeable, but as the muscles around it pull into a smile, its shortness creates divots in the face.