Dr. Greene`s Answer:
A little hole at the base of the tailbone is called a sacral dimple or a sacral pit. Some of these are shallow and have a smooth end. Stool can collect in here. The treatment is to keep it clean, and to apply a protective barrier diaper ointment to try to keep stool out. Keeping stool out will be much easier when she is out of diapers.
A sacral dimple is common in normal, healthy children, but…
Some 1sacral pits continue deep inside, and may even connect to the spinal canal or even the colon. In the latter case, bits of stool can leak out through the opening. There can be a chronic rash. This type of dimple needs to be closed.
Some sacral dimples are outward signs of underlying problems. Most babies whose sacral dimples are within the crease between their buttocks are healthy.
Dimples that are deep, large, above the crease, or associated with an overlying birth mark or patch of hair should be looked at radiographically to be sure how and where they end. An MRI can give a conclusive answer. An ultrasound is easier and less expensive — and in babies it can often settle the question.
1 Pediatric Clinics of North AmericaVolume 47;Number 4;August 2000Copyright © 2000 W. B. Saunders Company CUTANEOUS SIGNS OF NEURAL TUBE DYSRAPHISM]