The vertebral arteries are paired arteries that arise from the subclavian arteries, travel upward through the transverse foramina of the cervical vertebrae, and enter the skull to join and form the basilar artery, which supplies the posterior part of the brain (brainstem, cerebellum, occipital lobes). On ultrasound, the vertebral arteries are evaluated in the neck between the cervical vertebrae for flow direction, velocity, and patency. Normal flow is directed toward the brain (antegrade). Reversed (retrograde) vertebral artery flow is the hallmark of subclavian steal syndrome. Stenosis, occlusion, and hypoplasia of the vertebral arteries can all be detected. Vertebral artery evaluation is a standard component of the carotid duplex examination and is important for assessing overall cerebrovascular health.
Sonography Term