In medicolegal age estimation, the iliac crest apophysis fusion (Risser sign) is widely used. Risser grade 4 indicates:

• A The iliac apophysis is completely fused to the iliac crest — skeletal maturity complete
• B Ossification has reached the midpoint of the iliac crest
• C The iliac crest apophysis has ossified from ASIS to PSIS (cap complete) but not yet fused to the iliac crest ✓
• D Ossification is entirely absent from the iliac crest

Explanation

The Risser sign grades iliac crest apophysis ossification: Grade 0 — no ossification; Grade 1 — up to 25% ossified (lateral ASIS); Grade 2 — 25–50%; Grade 3 — 50–75%; Grade 4 — 75–100% ossified (cap complete from ASIS to PSIS) but not yet fused to the crest; Grade 5 — complete fusion to the iliac crest (true skeletal maturity, approximately 14–15 years in girls, 16–17 years in boys). Risser 4 means the cap spans the entire crest length but remains unfused. In scoliosis management (Cobb angle), Risser 0–1 indicates high growth potential and risk of curve progression.

Reference: BD Chaurasia's Human Anatomy, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.