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Frontal bossing refers to prominent, protruding forehead bones, typically due to abnormal growth or expansion of the frontal bone.
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Frontal bossing can result from overgrowth, increased intracranial pressure, or abnormal mineralization of bone.
| Condition | Notes |
|---|---|
| ‣ | Disproportionate dwarfism, frontal bossing with midface hypoplasia |
| ‣ | Delayed cranial suture closure, wormian bones, dental anomalies |
| ‣ | Craniosynostosis with shallow orbits and proptosis |
| ‣ | Syndactyly + craniosynostosis + frontal bossing |
| Hurler syndrome (MPS I) | Coarse facies, macrocephaly, corneal clouding, short stature |
| Russell-Silver syndrome | Triangular face, short stature, frontal bossing |
| Hydrocephalus | Bossing from increased intracranial pressure |
| Condition | Mechanism |
|---|---|
| Thalassemia major | Marrow hyperplasia due to chronic anemia causes calvarial expansion |
| Sickle cell anemia | Same mechanism as above, though less severe |
| Congenital hemolytic anemias | Marrow expansion |
| Condition | Notes |
|---|---|
| Rickets | Vitamin D deficiency causes defective mineralization → soft skull with bossing |
| Congenital hypothyroidism (cretinism) | Delayed bone age, macroglossia, umbilical hernia, frontal bossing |
| Feature | Description |
|---|---|
| Prominent forehead | Visible and palpable projection of the frontal bone |
| Head shape | May be dolichocephalic, brachycephalic, or have craniosynostosis |
| Associated symptoms | Vary with underlying condition: growth failure, coarse facies, macroglossia, dental anomalies, skeletal deformities, developmental delay |
| Condition | Finding |
|---|---|
| Thalassemia, sickle cell | Thickened calvarium with hair-on-end appearance |
| Achondroplasia | Frontal bone protrusion with midface hypoplasia |
| Cleidocranial dysostosis | Delayed closure of fontanelles, wormian bones |
| Apert or Crouzon syndrome | Suture fusion (craniosynostosis) |
| Rickets | Soft calvarium with widening of sutures |