Post-contrast CT scan of the neck showing the left common carotid artery (A) and left internal jugular vein (B). Arrows indicate the extent of the thrombosis and the filling defect of the left internal jugular vein at the level of the thyroid cartilage, extending superiorly to the base of skull. There was also fusiform thickening of the left sternocleidomastoid muscle (C) without a discrete collection.