Tuesday, October 21, 2014
Saturday, May 24, 2008 paulajsnider, Community Member, asks

Q: 2month old baby girl has a patch of hair in her butt crack about 1/2 in above her rectum. Why?

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Answers (4)
sue, Community Member
5/28/08 8:05pm

I'm sorry I was not able to find information on our site regarding this kind of symptom.  Is it possibleit is a birthmark of some kind?


All the best, sue

liam's_mom, Community Member
6/ 2/08 4:24pm

My guess is that it's a "sacral dimple".  Akron Children's Hospital has great info on their website:

A sacral dimple or sacral pit, also known as a pilonidal dimple, is an indentation or little hole in the crease between the buttocks and the base of the tailbone. This dimple generally develops as the spinal column is forming inside the mother's womb. To put it simply, if the inner tissues of the neural tube that forms the spinal column become malformed, the outside layer of tissue including the skin may not be smooth. This could mean that the outside layer formed with some dimples in it, which have no effect on the inner layers; or there could be a malformation of the inner layers, which have no effect on the outer layers. So a dimple in the lower back along the spine may be a simple divot in the skin, causing no problems whatsoever, or it may be the sign of malformation in lower tissue layers including the spine and spinal cord.

Most sacral dimples are harmless. However, some sacral pits continue deep inside and may even connect to the spinal canal or even the colon or large intestine. In the latter case, bits of stool can leak out through the opening causing a chronic rash. This type of dimple needs to be closed. Other signs that may indicate an abnormality in the lower spine include large or deep sacral dimples or dimples that are covered by hair or a birthmark.

Most spinal cord defects signaled by a sacral dimple may be adequately investigated by doing a thorough physical exam and, if needed, an ultrasound. For those in which there is a very high suspicion of a spinal cord defect, an MRI is usually performed. If these tests detect a problem affecting the spinal cord, the child may require surgery.

If you notice a deep or an unusual-looking sacral dimple on your infant, be sure to discuss it with your pediatrician.

Some things your pediatrician will look for include:

  • Can the floor of the pit or dimple be easily seen? When the bottom portion of a divot can't be seen, this may be an indication of a neural tube that never closed completely.
  • Does the pit have hair growing from it? This again makes a pit suspicious for deeper involvement.
  • Is the neurologic exam normal? If there is significant involvement of the spinal column, there may be weakness in the legs.
  • How high up on the back is the dimple? Most dimples very low on the back (just above the buttocks) are of little concern. The higher the dimple is, the more likely it is to be associated with defects in deeper tissues.
  • Are there signs of any other defects? The brain, spinal column, kidneys, as well as other structures form at the same time the neural tube closes. Therefore, if there are any malformations in any other parts of the body, it becomes more probable that the neural tube may be involved as well.

After doing an exam, your child's doctor will discuss what, if any, treatment is needed.

momwhohasbeenthere, Community Member
7/23/08 12:28am

Hi,  My daughter had the same thing and with a dimple and all the docs said it was fine and don't worry about it.  Well I worried about it and found a doctor who did a MRI and found that she had a tethered spinal cord. 


She had back surgery at 9 months and is doing well today.  A tethered spinal cord can lead to problems.


Have it checked out!

lisaz, Community Member
6/ 7/09 11:44pm

Hi- I saw your post on health central about your daughter's tethered spinal cord.  What kind of doctor did you see that found the issue.  My 6 month old girl has a long butt crack- can't think of a more descriptive way to explain it.  She had and ultrasound when she was one day old, and they said no worries, nothing internal was affected.  The pediatrician joked that the official diagnosis was "a dimple on her butt" and I'd never have to worry about her wearing low-rider jeans.


Still... I'm worried.  I've noticed that it's hairy in there, and just tonight the skin looks like it's breaking down a bit.  I've lost a bit of faith in my pediatrician, and I'm just not sure what sort of doctor to turn to next.


Thanks for any advice you can give!

S., Community Member
7/21/09 12:54pm

I just found out my great niece has this and she is having a MRI.  If there is a problem it is much better to find it out as soon as possible.  I found a good articule at: http://www.nasw.org/users/twoharts/osd.html please check it out.  God bless. S.

la_baby, Community Member
10/18/09 1:30am

A relative had this as well. It fell out tho when the head hair fell out. I think it's just a family trait.

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By paulajsnider, Community Member— Last Modified: 12/27/10, First Published: 05/24/08