A 36-year-old woman presented with right shoulder weakness after a left parotid tumor resection. The overall clinical presentation included severe paralysis and atrophy of the right sternocleidomastoid and upper trapezius, an absent right gag reflex, and diminished right posterior tongue pinprick sensation. A diagnosis of right-sided Vernet syndrome (cranial nerve IX, X, XI lesions) was made, presumably from compression of cranial nerves by internal jugular vein phlebectasia. To our knowledge, this is the first case report of spontaneous Vernet syndrome associated with internal jugular vein phlebectasia in the absence of other lesions of the jugular foramen.