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 datum. The horizontal datum is a series of data points on the surface of the earth. The horizontal datum is primarily used to measure the position of oneself on the Earth's surface (latitude and longitude). Various datums have been used in the past.