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 - parallel to or in the plane of the horizon or a base line; a horizontal surface. vertical, perpendicular - at right angles to the plane of the horizon or a base line; a vertical camera angle; the monument consists of two vertical pillars supporting a horizontal slab; measure the perpendicular height.