Read a skeletal survey by segment: which part of the limb is short (rhizomelic, mesomelic, acromelic), which part of the bone (epiphysis, metaphysis, diaphysis, spine), and the skull and pelvis — then match the pattern.
Orient first
- Achondroplasia is the commonest non-lethal dysplasia; osteogenesis imperfecta is the commonest cause of multiple fractures with bone fragility.
- The Nosology of genetic skeletal disorders groups the conditions (verify the current revision).
- Genetic testing confirms; the radiographic pattern directs it.
Acquire the study
- Skeletal survey: AP and lateral skull, AP chest, AP pelvis, AP and lateral spine, AP of one upper and one lower limb, PA hand and foot.
The manoeuvre
- Limbs: which segment is short — proximal (rhizomelic), middle (mesomelic), distal (acromelic).
- Epiphyses (small, irregular, stippled), metaphyses (flared, cupped), diaphyses (bowed, thin, fractures).
- Spine on the lateral radiograph: platyspondyly, vertebral beaking, interpedicular distance narrowing caudally (achondroplasia).
- Pelvis: iliac wing shape, acetabular roof, champagne-glass pelvic inlet.
- Skull: wormian bones, frontal bossing, skull base size; hands: trident configuration.
What confirms it
- A named pattern with confirmatory genetic testing.
What licenses you to exclude it
- A normal skeletal survey excludes a radiographically expressed dysplasia at that age.
The classic misread
- Calling osteogenesis imperfecta non-accidental injury or vice versa without the full survey and history.
- Judging proportions without age-matched norms.