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.
Horizontal means flat or having no slope or with a slope of zero or the like. It's just what you think it is. It has across to it, but no up or down aspect. A hori â¦ zontal line is one that follows the horizon, or is straight across from one side to the other.