Skin anatomy. Historical anatomical artwork of the human skin. The main diagram (lower centre) shows scalp hairs and sebaceous glands (yellow, near surface). The upper diagram shows ridges on skin from the hands (which gives rise to fingerprints). It also shows sweat ducts and pores. Skin blood vessels (upper left) and lymphatic vessels (upper right) are shown, as is the structure of the nails (side view at centre left; top view with the nail removed at centre right). The underside of a nail is at bottom left. The capillaries at bottom right show the structure of papillae (the touch sense organs). Artwork from The Nerves of the Human Body (Ed. Jones Quain, London, 1839).