Received: 20 February 2020
Accepted: 8 May 2020
First Online: 19 May 2020
Ethics approval and consent to participate
: The study has been approved by the ethics committee of the Medical University of Vienna (EK 1555/2015).
: The specimens used in this study were obtained from voluntary body donors who consented during lifetime to donate their body for research and teaching purpose to the Center for Anatomy and Cell Biology, Division of Anatomy, Medical University of Vienna.
: The authors declare that they have no competing interests.