Supplementary Table 1 Sample ID and CRL (mm) for the present study. CS, Carnegie stage; CRL, crown-rump length; HS, histological section; PCX-CT, phase-contrast CT; NA, not available value CS ID (HS) CRL (HS) ID (PCX-CT) CRL (PCX-CT 


Supplementary Figure 1

Schema of primary cartilaginous elements of the sphenoid during human embryonic period. 
AT, ala temporalis; AP, alar process; B, basisphenoid; ME, mesethmoid; MP, medial pterygoid process; OS, orbitosphenoid; PS, presphenoid 

Supplementary Figure 2

Examples of "mesenchymal cell condensation" which was counted as "1" in HS and PCX-CT (for Table 2 examination 

Supplementary Figure 4

Example of manual segmentation of the ala temporalis using 3D slicer (CS21 embryo). 
Most sphenoid elements were identified only by PCX-CT with no difficulty when we observed them by serial and multidirectional images using DICOM observing tools, while we needed to use HS in advance for identification of some unclear elements as the