Simple Dimples

Dr. Greene’s take on dimples…

Many healthy babies have small dimples on their lower backs. A mother who had just graduated from nursing school came to my office hours chat this week at Her baby had a sacral dimple like this. Her pediatrician told her not to worry about it and ordered an ultrasound in two weeks. Of course she worried – especially after a quick online search of sacral dimples raised questions of spina bifida and neurologic problems. So, at her request, I’m making what we chatted about available for others who are concerned about this — the simple dimple plan for parents.

The first thing that parents need to know is that sacral dimples and related findings are common: about 1 in 20 babies. And most babies with a midline sacral dimple are healthy. Occasionally, these can be a sign of a spinal problem underneath. Sometimes, they are not even true dimples at all, but narrow open tubes that connect to an internal structure such as the intestines or the spinal canal. How do you tell the difference between dimples to smile about, and those to look into further?

There are four simple things to consider:

Is the dimple

  1. deep (the bottom can’t be seen)
  2. large (>0.5 cm in diameter)
  3. high on the back (> 2.5 cm above the anus) or
  4. associated with other skin findings at the site of the dimple (a tuft of hair, a tail, or a Hemangioma)?

If the answer to any of these is yes, then a closer look, such as an ultrasound, may be in order to see what is underneath. Even so, in one study of babies who met at least one of these criteria, most of the dimples (60 percent) turned out to be normal findings in healthy kids. Most of the them that did turn out to be problematic were both high on the back and also associated with other skin findings.

Simple dimples that don’t meet any of the above criteria turned out to be normal findings in 100 percent of the babies studied. In otherwise healthy babies, no ultrasound or other workup is recommended for simple dimples.

Drolet BA – Cutaneous signs of neural tube dysraphism. Pediatr Clin North Am – 01-AUG-2000; 47(4): 813-23 Higgins JC – Simple dimple rule for sacral dimples. Am Fam Physician – 15-JUN-2002; 65(12): 2435 Kriss VM – Occult spinal dysraphism in neonates: assessment of high-risk cutaneous stigmata on sonography. AJR Am J Roentgenol – 01-DEC-1998; 171(6): 1687-92

Published on: July 26, 2005
About the Author
Photo of Dr. Alan Greene
Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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Recent Comments

my baby is 11 month old ,after delivery he has small range of difficulty of passing stool, we gone to hospital and we ordered to to barium x ray, the result was normal . after six month he starts to sits . he has abnormal eye movement, lower leg weakness , difficulty of eating and drinking by his will . i am stressed because of inability to walk

Thank you so much for this article!! My big, healthy baby boy was born with positional talipes. I was referred to a physiotherapist following his birth. She examined him and noticed he had a very small, shallow sacral dimple with a small (hardly visible) amount of hair above it. You could easily see the bottom of the dimple and it was very low down between the buttocks crack. She explained to me it could indicate spina bifida and that I should see a specialist. I walked out of the office and burst into tears driving home as I was in shock and so scared thinking the worst for my 4 week old baby. After a much calmer reaction from my GP and an ultra sound all of the results came back normal and at 10 months he was off and running (literally skipped walking). The conversation with the physio planted a seed though (also with how it was explained to me – as the association with the word spina bifida is a very serious one) I have since trawled the internet reading about all kinds of problems relating to it (occulta) which has caused me a lot of anxiety. Reading an article like this gives me some perspective about how common sacral dimples are and to be aware in case of any future issues, e.g. back pain etc but that it is highly unlikely. Thank you Dr Greene!! :)

I’m really starting to worry about my 12 month old son. He was born with a deep sacral dimple (Ihave never been able to find the bottom but the doctor said she did) that is more than 2.5 cm above the anus (about 5 cm). The doctor examined him at a week old and said that she could see that it was closed and she didn’t feel any further testing was necessary. He is now a year old and not walking. His upper body strength is incredible. He can pull himself up and lean over the top of the playpen, even though he is very small for his age. However, his legs are very weak. When you try to make him stands alone, his legs are very shaky and unstable. He army crawled for 5 months before he ever crawled on his knees. Even on his knees, his crawling looks odd. He kind of fish tails. He has been referred to physical therapy to build leg strength, but I’m starting to wonder if there isn’t something neurological causing his legs to be weak.