Portraiture, in the sense that we understand it today, is a difficult idea to get to grips with in the material of the pre-modern world. In the Middle Ages in particular, notions of the individual and the corporate often collided, and it can be difficult for the historian to unpick the network of links between portrait and personification, as well as between spiritual and corporeal personhood. But building on recent significant strides forward in understanding the medieval history of the genre, this paper seeks to bring the portraiture debate into the realm of medicine, addressing what is undoubtedly the weirdest portrait to survive from medieval England: a bizarre image of the famed proctological surgeon John Arderne.