Persistent carotid-vertebrobasilar anastomoses
The persistent carotid-vertebrobasilar anastomoses are variant anatomical arterial communications between the anterior and posterior circulations due to abnormal embryological development of the vertebrobasilar system. They are named, with the exception of the proatlantal artery, using the cranial nerves with which they run:
arises from proximal cavernous ICA most common persistent carotid-vertebrobasilar anastomosis two types - lateral and medial
Saltzman classification
type I: absent ipsilateral posterior communicating artery
type II: fetal origin of ipsilateral posterior communicating artery
persistent otic (acoustic) artery controversial, perhaps non-existent arises from petrous ICA rare, as it is the first anastomosis to regress persistent hypoglossal artery arises from cervical ICA at C1 to C3 levels persistent proatlantal artery
type I arises from internal carotid artery
type II arises from external carotid artery
A mnemonic to help remember these persistent carotid-vertebrobasilar anastomoses is HOT Pepper.