Question of the Month: I have a 3 ½-month old granddaughter who had a dimple at the base of her spine when she was born. When she was brought home her mother discovered that there was one dimple on each of her shoulders. My daughter was told that these could possibly be markers for some problem, like Spina Bifida. In all the reading that I have done nothing has mentioned anything about having dimples on shoulders. Unfortunately, she hasn't had her post natal examination yet. Have you come across the ones on the shoulders before and what could it mean?

This is an excellent and common question. Let me answer the easy part first. The dimples in the shoulder areas are not related to Spina Bifida. They are innocent and do not indicate any problem.

Now for the issue of the dimple at the base of the spine, also known as a sacral dimple or the fancier term, “coccygeal pit” — these are also almost always innocent and not related to Spina Bifida providing ALL of the following are true:

1. The dimple or pit is located within the crease between the two buttocks (also called the natal cleft or gluteal cleft).
2. The dimple is within 1 inch of the anus and is not bigger than ¼ inch in size.
3. The base of the dimple can be seen.
4. There is no hair, skin color change, blood vessels (telangiectasias), or blood vessel tumors (hemangiomas) around the spine.
5. There is no fatty mass felt under the skin.
6. The buttocks crease (gluteal cleft) is straight.
7. There are no abnormal neurologic findings on exam (i.e. weak legs, abnormal reflexes)

If ALL of these statements are true, then the baby can be followed. Quite rarely, the dimple itself can grow a hair or become infected, which would need further evaluation. Otherwise, nothing needs to be done, and problems are so infrequent that a preventive surgery is not advised.

Now if ANY of the above statements are not true or there are dimples higher up on the back (above the buttocks crease), further testing is advised.

The first step is to get an ultrasound of the area of the back where the dimple, hair tuft, skin color change, blood vessels, or fatty mass is located. If this is abnormal, then an MRI is usually requested to get a more detailed look. Since the ultrasound can be done without needing anesthesia, it is the first choice.

One last comment about skin color changes — a high percentage of non-white babies have a blue-gray discoloration in the buttocks area called Mongolian spots. Ninety percent of Native Americans, 80% of Asians, and 70% of Hispanics have Mongolian spots. Less than 10% of whites have Mongolian spots. By themselves, these color changes are also not related to Spina Bifida. They are innocent and generally resolve as the baby gets older. No additional testing is necessary as long as there are no other findings.

For more information on the genetics and factors associated with Spina Bifida, please visit the Spina Bifida Association fact sheet.

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