Online XR presentation of dicephalic parapagus full‐term conjoined twins collected by Dr. Jacob Henle

Abstract

Anatomical analysis of conjoined twins provides important information concerning embryological development. Museum specimens provide a unique sample that can be analyzed non-intrusively using advanced biomedical imaging and displayed online which is currently important due to limited in-person learning opportunities as a result of the COVID-19 pandemic. The purpose of this study is to create an extended reality (XR) workflow for visualization of dicephalic parapagus full-term conjoined twins obtained by Dr. Jacob Henle sometime between 1844-1852 for use in anatomy education. The workflow comprised image capture, segmentation, and visualization. The cadaver twins were curated at the University of Heidelberg and were subjected to CT and MR imaging. Relevant bones and soft tissues were manually segmented to create XR models, post-processed for visualization using Unity-based systems. A learning module was created and posted to Rad3d.com for presentation to students including visualization on Z-space computers (zspace.com) and sketchfab.com online. Osteology analysis showed commonality in the upper limb and shared ribs. Two vertebral columns were identified, and a single pelvic girdle was present with a single set of lower limbs. Duplicated supradiaphragmatic structures included two hearts (one with situs inversus) and four lungs, but single subdiaphragmatic visceral organs were observed. In particular, the gut was continuous on the right, but terminated at the distal esophagus on the left. One large liver occupied the abdomen with one large spleen located on the left. These observations suggest zygote fission was blocked near the yolk sac during midgut formation, but with secondary fusion of midline upper extremities and ribs. A radiology report was developed and presented to medical students as an embryology clinical correlation. This application indicates that university based museum specimens are useful as supplemental instructional subjects and, in this case, almost 170 years after arriving in the Department of Anatomy at the University of Heidelberg.