The polar easterlies are the dry, cold prevailing winds that blow from the high-pressure areas of the polar highs at the north and south poles towards low-pressure areas within the Westerlies at high latitudes.
Cold air subsides at the pole creating the high pressure, forcing a southerly (northward in the southern hemisphere) outflow of air towards the equator.
This outflow is then deflected westward by the Coriolis effect, therefore these prevailing winds blow from the east to the west.
Since the winds originate in the east, they are then known as easterlies.
Unlike the westerlies in the middle latitudes, the polar easterlies are often weak and irregular.