APPLIED RADIOLOGICAL ANATOMY

Detailed explanation-1: -Kidney development proceeds in three sequential stages along the urogenital ridge in a rostro-caudal direction, forming first the pronephros, followed by the mesonephros, and finally the metanephric kidney at the caudal end of the urogenital ridge.

Detailed explanation-2: -The metanephros is the final of three embryonic excretory organs that develop in a temporally and spatially distinct order, these being the pronephros, mesonephros and metanephros. The pronephros is the earliest to arise and the most primitive.

Detailed explanation-3: -Adjacent to the pronephric ducts, the intermediate mesoderm will condense to form non-functional nephron units, known as pronephroi, which will regress by day 25.

Detailed explanation-4: -Pronephros is the earliest nephric stage in humans, and constitutes the mature kidney in most primitive vertebrates. Mesonephros develops by the formation of mesonephric tubules from the intermediate mesoderm, it is the principal excretory organ during early embryonic life (4-8 weeks).