Vertebral artery occlusion at the narrowed "scalenovertebral angle": mechanical vertebral occlusion in the distal first portion.

We report a patient who developed occasional vertigo when turning his head to the right side. Occlusion of the right vertebral artery occurred at the narrowed "scalenovertebral angle" with this rotational head movement. This triangular tunnel consisted of the hypertrophied ligament of the longus colli muscle and the anterior scalene muscle. Decompression of these extraluminal compressive factors led to relief of the symptoms. Two different kinds of extrinsic compression at the first portion of the vertebral artery are discussed.