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.
In physics, the motion of a projectile can be broken down into two components: horizontal and vertical. In most cases, the vertical component is the motion caused by gravity acting on the object. For every object, gravity causes a constant acceleration towards the Earth at a rate of 32.2 ft/s 2, or 9.8 m/s 2. Horizontal motion is the movement of a projectile across a horizontal plane based on the force acting on it.