What makes concussions so dangerous? An expert explains

Taking a punishing hit on the football field or soccer pitch; having your head jostle around during a car accident; experiencing a fall from a ladder. An estimated 3.8 million concussions occur each year throughout the U.S. as a result of sports and non-sports activities. While their severity can fluctuate based on a number of factors, more than half go unreported. And their elusiveness to medical imaging makes proper diagnosis and recovery all the more important.