[O]ne of the more memorable examples was the woman who developed sexual feelings in her phantom foot. It turns out the parts of the brain that process sensory information for the feet are adjacent to those for the sexual organs (according to the Penfield map). Assuming that the latter brain area expands thanks to the sensory vacuum created by the missing leg, it seems reasonable to think that the feeling in the phantom limb might be a mixture between the two. This may also account for foot fetishes. Interesting.