Persistent primitive trigeminal artery

Last revised by Dr Mohamed Saber on 23 Aug 2022

Persistent primitive trigeminal artery (PPTA) is one of the persistent carotid-vertebrobasilar anastomoses. It is present in 0.1-0.6% of cerebral angiograms and is usually unilateral.

In utero, the trigeminal artery supplies the basilar artery before the development of the posterior communicating and vertebral arteries. The PPTA arises from the junction between petrous and cavernous ICA, and runs posterolaterally along the trigeminal nerve (41%), or crosses over or through the dorsum sellae (59%). Vertebral, posterior communicating and caudal basilar arteries are often hypoplastic. 

There are 2 types of PTA:

  • Saltzman type I: PTA supplies the distal vertebrobasilar arteries. The posterior communicating artery is absent and the caudal basilar is absent or hypoplastic with hypoplastic distal vertebral arteries.
  • Saltzman type II: PTA supplies the superior cerebellar arteries with the posterior cerebral arteries supplied by the posterior communicating artery.

Not all patients fall into this classification, however, with the PTA supplying the AICA territory also described 5

A characteristic tau sign 4 or trident sign is described as its appearance on sagittal CTA or MR images.

There is an association with intracranial aneurysms and vascular malformations.

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Cases and figures

  • Case 1
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  • Case 2
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  • Case 3 : showing "tau" sign
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  • Case 4
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  • Case 5
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  • Case 6
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  • Case 7
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  • Case 9
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  • Case 10
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  • Case 11
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  • Case 12
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  • Case 13: type II
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