They also can interfere with mental ability,make muscles weak and cause pain in the head.

VOA: special.2010.07.27

The RFL match review panel ruled that Fa'asavalu dipped into the tackle - and although Bailey did make contact with his head, it was with his shoulder and not an elbow or forearm and therefore was not illegal.

BBC: Leeds' Diskin cleared over tackle

It's a great head, but anyone can make mistakes with all that going on.

WSJ: Ravel| Mother Goose| New York Philharmonic| Arbie Orenstein

It seems he tried to make amends with an Instagram post where he insisted his head is screwed on right and that his family is proud of him.

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