The parents of an 18-month-old girl were curious about a depressed area on their daughter's lower back, which had been present at birth. The child was otherwise healthy.
Drs Alexander K. C. Leung and Justine H. S. Fong of Calgary, Alberta, made the diagnosis of sacral dimple. It is thought that a skin dimple develops in utero as a result of interposition of tissue between a sharp, bony point and the uterine wall; this leads to decreased subcutaneous tissue formation.
A sacral dimple is usually benign. However, it may herald an underlying developmental defect, such as spina bifida occulta and diastomyelia. A sacral dimple may be associated with several hereditary disorders, including Bloom; Smith-Lemli-Opitz; and 4p, or Wolf-Hirschhorn, syndromes.