Anatomical variants of the sacrum

Anatomical variants of the sacrum are incidental findings during radiological investigations but are clinically important for caudal epidural block.

  • angel-wing sacrum
  • accessory sacroiliac joints
  • complete agenesis of the dorsal wall of the sacral canal 
  • developmental defects in the ala of the sacrum
  • developmental absence of a portion of the right ala of S1
  • Midline cleft of S1
  • sacral ribs
  • spina bifida occulta of S1
  • sacral hiatus
  • sacral agenesis
  • lumbosacral transitional vertebrae
  • unfused ossification center for the superior facet of S1