Angiogram – trigeminal artery (PTA)

From WikiCNS

1. Present in .1-.6% of all angiograms
2. In utero, the embryonic trigeminal artery supplies the basilar artery before the PComm and vertebral arteries develop
3. PTA arises where the ICA exits the petrous carotid canal and enters the cavernous sinus; it runs posterolaterally along the trigeminal nerve or crosses over or through the dorsum sellae before joining the basilar artery
4. Patients with PTA have higher incidence of aneurysms and AVMs
5. Second most common persistent carotid verebral anastomosis is the persistent primitive hypoglossal artery (PHA)
   1. courses through the hypoglossal canal, parallels CN 12
6. less common persistent carotid-vertebrobasilar anastomoses are the persistent otic artery and proatlantal intersegmental artery
   1. persistent otic artery originates in the petrous ICA, projects through the internal auditory meatus and joins the caudal basilar artery
   2. persistent intersegmental artery is a suboccipital anastomosis between the ECA or cervical ICA and a vertebral artery; typically courses between the arch of C1 and the occiput