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.
Physics. a particular stage or point of advancement in a cycle; the fractional part of the period through which the time has advanced, measured from some arbitrary origin often expressed as an angle (phase angle) the entire period being taken as 360Â°.