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, rugby and 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.
Relationship to fencing reflex and posturing
The fencing response designation arises from the similarity to the asymmetrical tonic neck reflex in infants. Like the reflex, a positive fencing response resembles the “en garde” position that initiates a fencing bout, with the extension of one arm and the flexion of the other.