A measurement of the distance from the top of the fetus' head, also called the crown, to its rump at the end of the spine. This is abbreviated as CRL.
Crown Rump Length is usually abbreviated as CRL. It is the measurment of the length of the unborn human fetus from the top of the head (crown) to the bottom of the buttocks (rump). The fetus floats in the amniotic fluid inside the uterus of the mother usually in a curved posture resembling the letter C.