Vascular architecture of the human fetal adrenal gland: a SEM study of corrosion casts.

The vascular architecture of adrenal glands was investigated in human fetuses aged from 16 to 24 weeks, using microcorrosion casts and scanning electron microscopy. The fetal adrenals showed an arrangement of blood vessels remarkably similar to that described in adult glands. There was a clear centripetal pattern from superficial arteries and their branches, via irregular capillaries of the subcapsular plexus and definitive cortex, and then via the radial sinusoids and venous sinuses of the fetal cortex, to the central vein. Rare medullary arterioles traversed the cortex to break up into small local capillary networks in the central region of the gland. Some superficial capillaries were drained by occasional subcapsular veins. No portal system was observed in the fetal adrenals.