There is much discussion in the medical literature about the association between sacral dimples and occult spinal dysraphism. But, as any practicing pediatrician will tell you, small dimples near the top end of the gluteal crease are frequently encountered in newborns. How can you tell which ones deserve further evaluation?
A simple dimple is a small indentation of skin which is <5mm in diameter and <2.5cm above the anus. Most simple dimples are so low on the spine that they are actually located over the coccyx rather than the sacrum. This patient has a simple sacral dimple. This type of dimple is both common and benign. No further evaluation is needed.
This type of dimple is concerning. Further evaluation of the spine with ultrasound and/or MRI is recommended.Dimples that are more likely to be associated with an occult spinal dysraphism include those that are >5mm in diameter, >2.5cm above the anus, or present in combination with other dimples, hairy patches, birthmarks, skin tags, or masses. This patient has a high risk dimple.