1 If a lot of blood leaks out, it can cause a buildup of pressure in the brain because the brain is enclosed in the skull. There is no room for brain tissue to expand, and so the leaked blood can compress and kill important areas of the brain.  Hemorrhagic strokes tend to be more serious than ischemic strokes.
Horizontal definition, at right angles to the vertical; parallel to level ground. See more.
The horizontal effect is an apparent veering to the right or left of a straight-line path by an object moving horizontally; as viewed from space, the object is actually moving in as straight-line a path as possible, given the curvature of the Earth's surface.