Fig. 3: Pictorial timeline of the changing position of the developing right ventricle.
From: A pictorial account of the human embryonic heart between 3.5 and 8 weeks of development
The figure shows caudal (CS12 and CS13) or ventral views (CS14-23) of the heart lumen between CS12 and CS23. The difference in the viewing angle reflects the changing curvature of the embryonic axis. The position of the right relative to the left ventricle gradually changes over ~60° between CS12 and CS18 (graph; each dot represents a single embryo). The right ventricle is positioned caudally relative to the left ventricle at CS12 and achieves a more cranial position after CS18. The interventricular foramen is relatively long during CS12-14. The wide space between left and right ventricular lumens after CS20 reflects the appearance of compact myocardium and a thick muscular ventricular septum. The ventricular axes are almost sagittal prior to CS20, and become oblique and leftward at CS23, reflecting the changing shape of the rib cage212. All images are also available as preset views in the corresponding 3D-PDFs.
