Question:medium
A 16-year-old boy claiming to be 18 years old. Which 2 joints should be checked for age estimation?
A 16-year-old boy claiming to be 18 years old. Which 2 joints should be checked for age estimation?
Show Hint
Choose the two joints whose epiphyses are still fusing right in the 16–18-year window — the distal forearm and the joint just above the leg.
Updated On: Jun 22, 2026
- Wrist and knee
- Hip and elbow
- Hip and knee
- Head and shoulder
Show Solution
The Correct Option is A
Solution and Explanation
Pick joints whose epiphyses are actively fusing at 16-18.
The forensic question is whether the boy is 16 or 18. Bone age is read from which epiphyseal plates have closed, so the right joints are those that close within this narrow age band - a region that fuses at 12 or at 25 is useless because it looks the same at both 16 and 18.
The wrist. The distal radius and ulna are among the last forearm centres to fuse, closing roughly at 17-19 years. Reading the wrist therefore tells you whether the late-teen closure has happened - perfect for the 18-year claim.
The knee. The distal femur and proximal tibia/fibula epiphyses fuse around 16-18 years. Their state on X-ray brackets the lower end of the disputed range.
Because one of the two (knee) covers ~16 and the other (wrist) covers ~18, the pair together straddles the exact 16-18 gap and gives the most reliable answer.
Why the others fail: most elbow centres are already fused before 16 (too early), so an elbow film looks the same at 16 and 18; the skull sutures and the medial end of the clavicle fuse well into the twenties or later (too late) and so cannot fall between 16 and 18; and while the hip (iliac crest, head of femur) is useful, it is less discriminating than the wrist for this precise window. That leaves only the pairing that brackets both ends of the disputed range.
Therefore the two joints to radiograph are the wrist and knee (Option A).
The forensic question is whether the boy is 16 or 18. Bone age is read from which epiphyseal plates have closed, so the right joints are those that close within this narrow age band - a region that fuses at 12 or at 25 is useless because it looks the same at both 16 and 18.
The wrist. The distal radius and ulna are among the last forearm centres to fuse, closing roughly at 17-19 years. Reading the wrist therefore tells you whether the late-teen closure has happened - perfect for the 18-year claim.
The knee. The distal femur and proximal tibia/fibula epiphyses fuse around 16-18 years. Their state on X-ray brackets the lower end of the disputed range.
Because one of the two (knee) covers ~16 and the other (wrist) covers ~18, the pair together straddles the exact 16-18 gap and gives the most reliable answer.
Why the others fail: most elbow centres are already fused before 16 (too early), so an elbow film looks the same at 16 and 18; the skull sutures and the medial end of the clavicle fuse well into the twenties or later (too late) and so cannot fall between 16 and 18; and while the hip (iliac crest, head of femur) is useful, it is less discriminating than the wrist for this precise window. That leaves only the pairing that brackets both ends of the disputed range.
Therefore the two joints to radiograph are the wrist and knee (Option A).
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