A sacral dimple (also termed pilonidal dimple or spinal dimple) is a small depression in the skin, 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.
Sacral dimples are rare, occurring in up to 4% of the population. The majority of these dimples are minor and do not represent any underlying disease; however, the minority may be a sign of disease, notably spina bifida. Even so, this is usually the spina bifida occulta form, which is the least serious kind. Additionally, a sacral dimple may be indicative of a possible kidney problem that can be checked with an ultrasound.
Sacral dimples are usually spotted in post-natal checks by a pediatrician, who will check:
- whether the floor of the dimple can be seen to be covered with skin;
- whether there is a tuft of hair in the dimple;
- whether there any other problems such as weak lower limbs;
- the distance from the buttocks to the dimple (closer is better).
- Flannigan, edited by Christopher (2011). A practical guide to managing paediatric problems on the postnatal wards. Oxford: Radcliffe Pub. pp. 43, 44. ISBN 9781846195068.