Anatomy: The Allen Test for Assessing Blood Flow in the Arms
The Allen test is a procedure that helps evaluate blood flow in the arms by examining the radial and ulnar arteries. Positioned near the surface on the underside of the forearm, the radial artery can be easily accessed. When the palm is facing upwards, the radial artery aligns in the same direction. Due to its size and proximity to the skin, many individuals rely on the radial artery to check their pulse. In the hand, the ulnar artery connects with the radial artery. This interconnectedness proves advantageous in cases where one artery is unable to deliver sufficient blood to the hand, as the other artery can compensate by ensuring a proper blood supply.
Purpose of the Allen Test
The Allen test is conducted by doctors for various purposes. Its primary objective is to examine the ulnar artery. Due to the ulnar artery’s location, which is not easily accessible from the skin’s surface, it is more convenient to evaluate it by comparing it to the radial artery. The doctor’s aim is to ensure that the hand receives sufficient blood flow even when the radial artery is blocked off. By doing so, the test determines the efficiency of the ulnar artery.