A sacral dimple or pilonidal dimple is a small hole located just above the buttocks. The name comes from the sacrum, the bone at the end of the spine, over which the dimples are found. More than 2% of babies may have such dimples; almost all of these are very minor. However, it may be a sign of Spina bifida: even so this is usually the spina bifida occulta form which is the least serious kind. Sacral dimples are usually spotted in post-natal checks by a pediatrician, who will check:
Additionally, this can be indicative of a possible kidney problem, which is then checked by an ultrasound.