Background:
The aim of the study is to present a patient who suffered from severe vertigo with rare arterial vascular anomaly of the vertebrobasilar system.

Case Report:
A 56-year old female patient was urgently admitted due to dizziness, with a spinning motion toward the right, accompanied by nausea, vomiting, and diplopia which occurred on the morning of the day of admission and gradually intensified. The patient had laboratory tests, VNG, functional imaging of the cervical spine, CT of the head, CTA of the cranial arteries, and neurological and ophthalmological consultations. This demonstrated a vascular anomaly in which the basilar artery was an extension of the right vertebral artery, and the left atrophic vertebral artery extended into the posterior inferior cerebellar artery. Conservative treatment and motor rehabilitation gave very good therapeutic effects.

Conclusion:
In the presented case, the basilar artery was found to be an extension of the right vertebral artery, while the left atrophic vertebral artery extended into the posterior inferior cerebellar artery. The vascular anomaly, osteochondrosis of the C4/C5 cervical spine, and hyperlipidemia resulted in mixed-type vertigo with decreased excitability of the labyrinth on the affected (anomalous) side due to insufficient blood supply to the inner ear and lack of vascular compensation. The diagnosed anatomical anomaly of the vertebrobasilar system was not an indication for surgical intervention; instead, conservative treatment was successful.