Hair on end sign (mnemonic)

The hair on end sign refers to a radiographic appearance of the diploic space of the skull vault which results from a thickening of trabeculae as the diploic space expands. These trabeculae are perpendicular in orientation, interspersed by radiolucent marrow hyperplasia along the skull vault.

It is classically described with plain skull radiographs although can also be appreciated on CT or MRI 3. Causes include:



  • hereditary spherocytosis
  • iron deficiency anaemia
  • neuroblastoma
  • enzyme deficiency, e.g. G-6-PD deficiency causing haemolytic anaemia
  • sickle cell disease
  • thalassemia major
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Article information

rID: 9384
Section: Signs, Mnemonics
Synonyms or Alternate Spellings:
  • Hair on end appearance
  • Hair-on-end sign
  • Hair on end appearances

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Cases and figures

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    Case 1
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    Lateral skull rad...
    Case 2: in thalassemia
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    Case 3
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    Case 4
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