Renal ascension and Rotation
We’ll start with kidneys’ apparent ascent from the pelvis and 90-degree rotation as the embryo body lengthens in weeks 6-9.
We show the original location of the metanephros in anterior view:
The kidneys begin in the pelvic region, inferior to the aortic split. Indicate the renal hilum, which is where the ureter and renal vasculature enters the kidney; notice that it faces anteriorly.
The ureters descending to the posterior aspect of the urinary bladder.
Next, show that as the ureters lengthen, the kidneys "ascend" through the pelvic cavity while rotating, so that the hila begin to face each other.
Finally, in the mature form, the kidneys are located at the level of T12-L3. Notice that the right kidney lies a little lower than the left; this is due to the presence of the liver on the right side.
The paired renal arteries branch directly from the abdominal aorta and enter the kidney at the hilum with the ureter; though not shown, here, the renal veins drain blood from the kidneys to the inferior vena cava.
