Fig. 3

1D Core Model depicted as a graph, with nodes representing anatomical landmarks and edges representing anatomical regions. Regions are generally delimited by their start and end landmarks. The rectum has an additional intermediate landmark known as the anterior peritoneal reflection (APR) and the caecum has an additional intermediate landmark known as the ileocaecal valve (ICV). In the context of the large intestine, the latter is referred to as the ileocaecal valve-caecum centreline (ICVc), whereas the end point for the small intestine is labelled as the ileocaecal valve-ileum (ICVi). Numbers in nodes represent the landmarks’ distances (in mm) to the anus (for large intestine) and the ICVi (for small intestine). Numbers on links represent the lengths (in mm) of the corresponding gut region. The numbers shown in this diagram reflect a typical live human’s anatomy, different patients will have different measurements