A 40-year-old man presented with left-arm weakness, facial palsy, and dysarthria. Magnetic resonance imaging(MRI)revealed acute-stage cerebral infarction in the internal watershed area of the right hemicerebrum and MR angiography(MRA)demonstrated 56% stenosis of the right common and internal carotid arteries. Computed tomography(CT)scan showed no calcification and a stenotic lesion of the right common carotid artery, adjacent to the prolonged greater horn of the right hyoid bone. Because no other causes were found for the cerebral infarction, the compression of the stenosis of the right carotid artery was suspected as the cause of the cerebral infarction. Carotid arterectomy was performed five months after onset. Intraoperative finding showed tight adhesion between the carotid sheath and the adventitia of the carotid artery. Pathological findings showed a proliferation of fibroblast cells in the resected plaque. Common or internal carotid artery stenosis related to compression from the hyoid bone is rare. These cases hold a potential for tight adhesion around tissues. Therefore, in cases of prolonged hyoid bone, increased attention should be given to the operative procedure.