This report describes recently treated patients with carotid artery dissection caused by blunt softball injuries, as well as the results of a study of carotid artery trauma in a community. Data obtained through the medical records linkage system used for epidemiologic studies in Olmsted County, MN were used to identify all cases of traumatic internal carotid artery dissection diagnosed from 1987 through 1994. Four patients with traumatic internal carotid artery dissections were identified during the 8-year period under study. In two patients (50%) the carotid dissection was a result of the direct impact of a softball. A 39-year-old-man, who developed transient cerebral ischemic symptoms, and a 35-year-old woman, who developed a painful Horner's syndrome, were struck by a softball on the anterolateral aspect of the neck. Both patients had a low carotid bifurcation. These data suggest that internal carotid artery dissections may be underrecognized sequelae of direct softball injuries to the anterolateral neck. A low carotid bifurcation may be a risk factor for such injuries.