Allen's test

Hey guys, so I was just fascinated about this test. Probably it's because my friend is as pale as
Hey guys, so I was just fascinated by the test. Turned my friend from a Radish to a Beetroot.
Allen's test - to know the patency of radial and Ulnar arteries, in Peripheral Arterial Diseases (Surgery)
Procedure:
The patient is asked to clench his fist tightly. The surgeon presses on the radial and Ulnar arteries at the wrist.
After 1 minute, the patient is asked to open the fist. The Palm appears white. Now pressure on the radial artery is removed and the change in the colour of the hand is noted.
If the Radial artery is 'blocked', the colour remains white.
But if it is patent, the palm assumes normal colour.
Same is repeated for the other artery.