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Pelvic Rib or Digit

General Considerations


  • Rare congenital anomaly
  • Bone develops in soft tissue
  • Can arise from any of the pelvic bones; also anterior abdominal wall
    • Most commonly arises from ilium
  • Unilateral
  • Believed to arise in mesenchymal stage of bone growth within first 6 weeks of embryogenesis
  • May present as rib-like or finger-like structures with one or more (pseudo-) joints

Clinical Findings

  • Usually asymptomatic; discovered incidentally

Imaging Findings

  • Digit or rib has cortex and medulla
  • “Finger” is typically segmented with pseudo-articulations
    • May contain 2, 3 or 4 segments
  • May or may not pseudo-articulate with the axial skeleton

Differential Diagnosis

  • Heterotopic ossification – frequently a history of prior trauma
  • Avulsion fracture of the pelvis
  • Ossified scar – in subcutaneous tissue
  • Fong's disease (onychoosteodysplasia) – iliac horns


  • No treatment is required

pelvic digit rib finger

pelvic digit rib finger

Pelvic Digit. (Above). Frontal and lateral radiographs of the hip demonstrate a well-corticated bony protuberance arising from the region of the right pubic bone with a suggestion of segmentation (yellow and white arrows). (Below) A coronal reformatted CT image of the pelvis confirms the presence of the pelvic digit with pseudo-articulations (white circle).
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The pelvic digit: a harmless “eleventh” finger. IV Breuseghem. British Journal of Radiology (2006) 79, e106-e107


Pelvic digit as a rare cause of chronic hip pain and functional impairment: a case report and review of the literature. M Maegele. Journal of Medical Case Reports 2009, 3:139 doi:10.1186/1752-1947-3-13