To understand what a stroke is, why it does what it does, and why making a recovery prognosis is sketchy at best, you must first understand some basic anatomy of the brain. The human brain is in constant need of oxygen and nutrients. The brain gets these necessities from blood vessels. Blood reaches the brain via two vast arteries located on either side of the neck. These are the carotid arteries. The carotids branch out several times into many smaller blood vessels that feed all areas of the brain. A CVA (stroke) occurs when one of the blood vessels feeding the brain stops supplying blood to a particular area of the brain. This may occur due to hardening of the artery, an embolism that dams up a blood vessel, or the blood vessel begins to bleed. Brain tissue that is deprived of oxygen and nutrients for a period of time dies. Brain tissue does not regenerate. The effects of a stroke will vary greatly depending on what area of the brain has died and how large the area is. Some stroke victims are paralized on one side of their body, some can no longer speak, some have difficulties swallowing, some suffer "brain death", others simply die. Strokes are the third leading cause of death in the United States. After a patient suffers a CVA, there are two major goals. Prevention of another stroke through anticoagulant medications, and agressive rehabilitation through physical and occupational therapy. The degree of rehabilitation is generally an unknown. Some recover fully, while others don't. To answer why to this question would be a thesis not a webpage. There are an infinate number of factors, one of which is the mystery of the human brain itself. After the initial hospitalization following the stroke, a patient may be advised to go to a facility specializing in rehab for stroke victims. This is not a nursing home, nor the club med. Patients there are monitored carefully by nursing staff, and physical therapy as well as occupational therapy occur on a daily basis. There is hope for a good recovery when the patient is willing to work with his therapists, and he is surrounded by a loving group of family and friends.