(A) This image, taken at a public lecture by Wilhelm Röntgen, is reported to be the hand of the preeminent anatomist Albert von Kölliker.8 Radiographs of the hand were commonly made in the months following Röntgen's discovery, as demonstrations at scientific meetings and to “test” equipment before use. (B) Modern radiograph of a hand: a, blackened area of the film representing that area where only air is interposed between the beam source and the film; b, gray shadow where soft tissues absorb part of the beam before it reaches the film; c, mostly white area where calcium salts in bone absorb more x-rays than soft tissues do and the film is exposed only lightly; d, solid white area where the dense metal of the wedding ring absorbs all of the x-rays and so no area of the film is exposed underneath it. Note that in contrast to the historic x-ray image in part A, this is a doubly reversed print. This is what the clinician sees when he or she views radiographs on film or when radiographs are printed for publication. Source: GENERAL PRINCIPLES OF MUSCULOSKELETAL IMAGING, Fundamentals of Musculoskeletal Imaging Citation: McKinnis LN. Fundamentals of Musculoskeletal Imaging; 2014 Available at: http://fadavispt.mhmedical.com/DownloadImage.aspx?image=/data/books/1899/mckfunda_fig-1-02.png&sec=141188346&BookID=1899&ChapterSecID=141188303&imagename= Accessed: October 29, 2017 Copyright © 2017 McGraw-Hill Education. All rights reserved