Received: 9 April 2020
Accepted: 30 November 2020
First Online: 9 December 2020
Ethics approval and consent to participate
: This study was approved by the institutional review board of Tokushima University Hospital (approval number: 2068) and performed in accordance with the 1964 Declaration of Helsinki and its later amendments for comparable ethical standards. The cadaveric specimens used in this study were provided by the Clinical Anatomy Education and Research Center at Tokushima University Hospital. All donors had dedicated their bodies to education and research during their lifetime.
: Not applicable.
: The authors declare that they have no conflict of interest or sources of financial support for the publication of this article.