Dimple in the Back

Why is the pediatrician looking at my baby’s butt crack so intently? What a weirdo. Hold up, let me explain. When babies are formed in the womb, the nervous system gets formed in a super cool way. The cells that make up the nervous system and spinal cord sort of get zippered down the middle of the back. At the very end of the zipper, you have the sacrum or tailbone area of the baby. Often there is a remnant at the base of the spine and top of the butt crack called a sacral dimple or small pinpoint indentation that we can see on exam. This is a very normal thing and most babies have some remnant of the zippering like this. But in some babies, the dot is bigger than it should be, or is deeper than it should be, or is in a spot that is not near the butt crack, or there is a hair coming out from the odd dimple, which could be a sign that the nervous system zippering did not complete as it should have. These cases are super rare, but we never want to miss them as this requires a prompt MRI or ultrasound to make sure the spinal cord and spinal column are formed correctly. So, I apologize for being so forward, but pediatricians gotta look at new babies’ butt cracks.