Researchers show how side hit to the head could damage brain, lead to concussion

Play contact sports for any length of time and at one point or another you're probably going to have your 'bell rung' by a powerful blow to the head from a hard hit or fall. Rising awareness of the severe, abiding repercussions of strong impacts to the head—concussions, mild traumatic brain injury, neurological disorders—have led scientists to focus on what exactly happens inside a skull during a big hit.

source https://www.lifetechnology.com/blogs/life-technology-news-blog/researchers-show-how-side-hit-to-the-head-could-damage-brain-lead-to-concussion