These illustrations are based on the diagrams from "Sobotta's Textbook and Atlas of Human Anatomy 1908", the copyright of which has lapsed. The source files were obtained from Wikimedia Commons, and are listed below. 

The images have been edited to remove labels, change contrast and slightly tweak some details. 

Source files: https://commons.wikimedia.org/wiki/File:Sobo_1909_628.png