Fig. 10

Changes in colonic topography during the herniation and postherniation period. Left-sided views of reconstructions of the colon (panels a1-d1) and the colonic mesentery (panels a2-d2; purple edge) of CS18 (panel a; s97), CS23 (panel b; s48), 9.0 weeks (panel c; s89), and 9.5 weeks (panel d; s57) embryos. Note the boundary (*) between the horizontal, herniating proximal colon and the vertical, intra-abdominal distal colon at the colic bend. The asterisk also identifies the boundary between the cranial branches of the SMA (originating at Th12/L1) and the ascending branch of the inferior mesenteric artery (originating at L2/L4). The appendix and a few distal coils were still located in the hernial sac at 9.0 weeks and had just passed the hernial rim at 9.5 weeks. Panels e and f show the mesentery of the proximal colon of a CS18 (s97) and a 9.5 week embryo (s57), respectively. The mesentery of the proximal colon is attached to the mesenteric rod (stippled arrows in e1 and f1,3), whereas that of the distal colon is attached to the dorsal midline (arrows in e2, f1,2). Note leftward change in position of distal colon and mesentery between panels e2 and f. Interactive 3D-PDFs are available online (3D-PDF CS14, CS16, CS20, CS23, and 9.0 and 9.5 WKS)