This is an artistic illustration of the human trunk muscles from the book Anatomy for Artists by Eugene Wolff.
This is truly an artistic illustration of the human trunk muscles complete with pointers and labels for each muscle. The Anatomy for Artists book is the 3rd edition dated 1938 illustrated by George Charlton.
This is an original scan of the page:
This is my cleaned up version:
This is an original scan of the trunk muscles from the side:
This is the back view of the trunk:
I have many illustrations still to add from this book but in the meantime check out my gallery of free anatomy illustrations to find other parts of the body you wish to download.