Transverse section of forearm. Historical anatomical artwork of a transverse section through the middle third of a forearm, showing the internal structures surrounded by layers of fat (yellow) and skin (pink). The two bones are the radius (right) and the ulna (left). Several sets of muscles (red) are shown, surrounded by muscle membranes (white). Nerves (white), arteries (red) and veins (blue) are also shown. The main nerve (centre) is the median nerve. Either side of the arm are the bundles of the ulnar artery, veins and nerve (left), and the radial artery, veins and nerve (right). In between the bones are the interosseous artery and veins. Artwork from Atlas and Epitome of Operative Surgery (1898, Otto Zuckerkandl).