Vernon Davis hasn't shown up in a seahawks game since this happened (legal hit)
http://en.m.wikipedia.org/wiki/Fencing_response
The*fencing response*is a peculiar position of the arms following a*concussion. Immediately after moderate forces have been applied to the*brainstem, the forearms are held flexed or extended (typically into the air) for a period lasting up to several seconds after the impact. The fencing response is often observed during athletic competition involving contact, such as*American football,*hockey,*rugbyand*martial arts. It is used as an overt indicator of injury force magnitude and midbrain localization to aid in injury identification and classification for events including, but not limited to, on-field and/or bystander observations of sports-related head injuries.[1]