The screw-like ascent of the sweat ducts as an indicator of the analogous screw-like ascent of germinative material in the epidermis.
D004848:Epithelium / Q000033:anatomy & histology*; D006801:Humans; D012867:Skin / Q000033:anatomy & histology*; D013545:Sweat Glands / Q000033:anatomy & histology*