Rickets
- Defective mineralisation of the growth plate (zone of provisional calcification). Nutritional vitamin D deficiency commonest; also renal (osteodystrophy), hypophosphataemic (X‑linked), vitamin D‑dependent.
- Peak 6–18 months; best seen at sites of fastest growth: distal ulna/radius (wrist), distal femur/proximal tibia (knee), anterior rib ends.
- Widening of the physis, loss of the zone of provisional calcification, cupping, splaying (flaring) and fraying of the metaphysis, generalised osteopenia, delayed epiphyseal ossification.
- Rachitic rosary (costochondral junction enlargement), Harrison's sulcus, bowing (genu varum toddlers; valgum older), craniotabes, frontal bossing, triradiate pelvis, Looser zones (older children).
- Healing: dense metaphyseal band (re‑mineralised zone of provisional calcification) appears within ~3–4 weeks of treatment.