knee-jerk reaction. Fig. an automatic or reflex reaction; an immediate reaction made without examining causes or facts. With one of his typical knee-jerk reactions, he said no immediately, citing some moral argument that no one understood. See also: reaction.
What did you see when the patients head was rolled to the opposite side? In horizontal canal BPPV, you should have seen a direction change. When the horizontal nystagmus is geotropic, the BPPV is suspected to be canalithiasis, occurring on the side with the more intense nystagmus.
The large scale horizontal flow of air in the atmosphere is driven by the imbalance of net radiation over the globe (Fig. 1, more on that next week). This section introduces us to the physical laws governing the horizontal motion of air. It also describes types of motion systems encountered in the atmosphere.