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Atlas of Human Embryos Chapter   Figure

L-4 spinal ganglion, L-5 spinal ganglion, S-1 spinal nerve, S-2 spinal nerve, allantois, cloacal membrane (urogenital part), dorsal mesentery, extensor muscles of leg, fibula, flexor muscle of leg (calf), intervertebral disc, junction of superior mesenteric and vitelline arteries, marginal vein, median sacral vein, muscularis, notochord, parasympathetic neuroblasts, rectum, sacral plexus, sciatic nerve, sympathetic trunk, tarsus, umbilical coelom, urogenital fold, urogenital sinus (phallic portion), urorectal septum, vitelline (omphalomesenteric) vein

A section through the L-5 spinal ganglion and the phallic portion of the urogenital sinus.

Observe:
1. The superior mesenteric artery leaving the dorsal mesentery to become the vitelline artery.
2. The urogenital part of the cloacal membrane between the urogenital folds.
3. The phallic portion of the urogenital sinus separated from the exterior by the urogenital part of the cloacal membrane.
4. The urorectal septum separating the urogenital sinus and rectum.


Keywords: L-4 spinal ganglion, L-5 spinal ganglion, S-1 spinal nerve, S-2 spinal nerve, allantois, cloacal membrane (urogenital part), dorsal mesentery, extensor muscles of leg, fibula, flexor muscle of leg (calf), intervertebral disc, junction of superior mesenteric and vitelline arteries, marginal vein, median sacral vein, muscularis, notochord, parasympathetic neuroblasts, rectum, sacral plexus, sciatic nerve, sympathetic trunk, tarsus, umbilical coelom, urogenital fold, urogenital sinus (phallic portion), urorectal septum, vitelline (omphalomesenteric) vein

Source: Atlas of Human Embryos.