Foto: "<a href="https://ccnull.de/foto/glisson-loop-on-a-white-background-a-device-for-the-treatment-of-cervical-vertebrae/1016212" target="_blank">Glisson loop on a white background, a device for the treatment of cervical vertebrae</a>" von <a href="https://ccnull.de/fotograf/marco-verch" target="_blank">Marco Verch</a> via <a href="https://ccnull.de" target="_blank">ccnull.de</a> - <a href="https://www.flickr.com/photos/30478819@N08/50622082448/" target="_blank">Bildquelle</a>, <a href="https://creativecommons.org/licenses/by/2.0/de/" target="_blank">CC-BY 2.0</a>