A section through the T-8 neural crest, L-4 somite and aortic bifurcation.
Observe:
1. The caudal extent of the postcardinal vein.
2. The caudal end of the mesonephros (L-4 somite).
3. The origin of the right and left common iliac arteries at the bifurcation of the dorsal aorta.
4. The caudal extent of the gonadal ridge just medial to the mesonephros.
5. The sclerotome cells between the notochord and the T-8 myotome.
Keywords: L-4 somite, T-8 myotome, T-8 neural crest, T-9 dermatome, bifurcation of dorsal aorta, dorsal aorta, dorsal mesentery, gonadal ridge, lateral segmental artery, left common iliac artery, median sacral artery, mesonephric duct, mesonephric vesicle, notochord, postcardinal vein, right common iliac artery, sclerotome
Source: Atlas of Human Embryos.