Trident sign (persistent trigeminal artery)

The trident sign of a persistent primitive trigeminal artery refers to the appearance of the intracranial circulation on lateral projection. The internal carotid artery, the abnormal vessel and superior portion of the basilar artery resemble the Greek letter tau (thus tau sign). This configuration is also referred to as the trident sign 1, although, as there are only two upwardly pointing branches (terminal ICA and basilar artery) this would probably be better termed a bident. 

History and etymology

The trident is most commonly associated with the sea god Poseidon in Greek mythology or Neptune in Roman mythology.

Poseidon's older brother, Hades/Pluto has a two-pronged staff, known as a bident, which is actually a better fit for the morphology of this abnormality 2

Inspired signs
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Article information

rID: 65433
Section: Signs
Synonyms or Alternate Spellings:

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Cases and figures

  • Case 1
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