Objective: We previously suggested that aberrations of the carotid arteries, which may occur when the neck is bent forward, should be considered as new risk factors for ischemic stroke. We analyzed the results of carotid artery ultrasound examination in previous case and control groups, focusing in particular on the atherosclerotic risk factor in stroke, to determine the significance of arterial aberration and its relation to ischemic stroke. Data Sources and Review Methods: We analyzed the original data from our previous 235 casecontrol study patients among those who underwent complete routine cervical ultrasound and had all cholesterol data available. Results: Although plaque was present in the CCA in about one-half of the control group, none had experienced a stroke. At the same time, two-thirds of the case (stroke) patients had plaque in the CCA. This indicates that plaque tends to be a risk for stroke, although the difference between the two groups was not statistically significant. Conclusion: The results of the present analysis indicate that: 1) the degree of atherosclerosis was the same in both the case and control groups, because there were no statistically significant differences between them in cholesterol values; 2) the only difference between the two groups was the aberration of the carotid artery; and 3) aberration of the carotid artery tends to be a risk factor for stroke. The mechanism of cerebral infarction is speculated to be artery-to-artery embolism from the carotid plaque. The aberration of the carotid artery occurs, which triggered by plaque reaching the cerebellum.