Risser classification

The Risser classification is used to grade skeletal maturity based on the level of ossification and fusion of the iliac crest apophyses. It is primarily in planning corrective surgery for scoliosis.


  • stage 0: no ossification center at the level of iliac crest apophysis
  • stage 1: apophysis under 25% of the iliac crest
  • stage 2: apophysis over 25-50% of the iliac crest
  • stage 3: apophysis over 50-75% of the iliac crest
  • stage 4: apophysis over >75% of the iliac crest
  • stage 5: complete ossification and fusion of the iliac crest apophysis

As stage 0 and stage 5 can appear similar, age and long bone growth plates may be of help in discriminating the two. A patient with stage 0 will still have open growth plates in most of the long bones and will likely be younger than age 16 (female) or 18 (male). A patient with stage 5 will have no open growth plates in the long bones.

The above mentioned classification is the U.S. Risser staging system. The French Risser staging system has stage 4 representing complete ossification and fusion and divides the partial fusion into three thirds, i.e. stage 1-2-3 representing 0-33%, 33-66% and >66% of fusion.

Article information

rID: 31917
Synonyms or Alternate Spellings:
  • Risser
  • Risser grading

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Cases and figures

  • Case 1
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  • Case 2: Risser stage 4
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