Pretty often, when we're searching for images for mental_floss stories, we'll come upon a photo that's weird and delightful—something that makes us want to know more. Such was the case with this photo, an illustration circa 1910 that shows a man adopting four positions before an X-ray.
I can't find this photo anywhere else, so information is scarce. I did attempt to translate the captions, written in German, into English. According to Google Translate, "Lagerung bei einer frontalen schädelaufnahme" means "Storage at a frontal skull shot." So this must be the pose you adopt if you're getting your skull X-rayed. It makes sense; his head is tied into place, I assume to keep it from moving and messing up the X-ray.
Google translate says the second caption, "Lagerung bei einer Handgelenksaufnahme," means "Store at wrist recording." So this is how you'd get your wrist X-rayed. Like the man's head in the first photo, his wrist is secured in place in this image.
Sadly, the captions on the last two images are cut off, but we can assume, based on the model's position, that his chest and his back are being X-rayed, respectively.