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.
1. a flat or level surface. 2. Geom. a surface generated by a straight line moving at a constant velocity with respect to a fixed point. 3. an area of a two-dimensional surface having determinate extension and spatial direction or position: horizontal plane.