The second impact in catastrophic contact-sports head trauma.
D000328:Adult; D001265:Athletic Injuries / Q000000981:diagnostic imaging; D001924:Brain Concussion / Q000000981:diagnostic imaging; D005538:Football; D006408:Hematoma, Subdural / Q000000981:diagnostic imaging; D006801:Humans; D008297:Male; D011859:Radiography