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. Mathematics A line or plane perpendicular to a given line or plane. 2. A perpendicular position. 3. A device, such as a plumb line, that is used in marking the vertical from a given point. 4. A vertical or nearly vertical line or plane.erpendicular. adj. 1. (Mathematics) Also: normal at right angles to a horizontal plane. 2. (Architecture) denoting, relating to, or having the style of Gothic architecture used in England during the 14th and 15th centuries, characterized by tracery having vertical lines, a four-centred arch, and fan vaulting.