An terior cerebral artery A1 segment hypoplasia is an uncom-. mon fetal variant of the circle of Willis. The frequency of this. congenital variation is 1â13% as derived from angiograms. and autopsy reports. Impaired collateral blood flow through. the circle of Willis is a recognized risk factor for ischemic. stroke. The A1 segment of the anterior cerebral artery is a. principal supplier of anterior collateral blood flow.
George Washington, 1799. Printer Friendly Version >>>. George Washington finished his second term as the first President of the United States in 1797. Weary of the political infighting surrounding the presidency, he longed for the peace of retirement to his beloved Mount Vernon.
George Washington was an American statesman and soldier who served as the first President of the United States from 1789 to 1797 and was one of the Founding Fathers of the United States. He served as Commander-in-Chief of the Continental Army during the American Revolutionary War, and later presided over the 1787 convention that drafted the United States Constitution. He is popularly considered the driving force behind the nation's establishment and came to be known as the father of the country