Page 14 - Microsurgery

ALLEN Test

This diagnostic test is used to assess the vascularization of the radial and ulnar arteries. After
asking the patient to clench their fist, the examiner instructs them to extend their fingers.
With both arteries compressed, as shown in the upper left image, there is no vascularization
visible in the hand.

When the ulnar artery is released, there is still no vascularization in the digits, indicating that
arterial flow is interrupted. In this case, it was due to thrombosis of the ulnar artery at the
hypothenar eminence (hammer syndrome).

When the radial artery is released, blood flow is restored. This test is important for diagnosis
and also for planning a radial artery-based free flap (Chinese flap). In such cases, both
arteries must be patent to proceed with a Chinese flap.

13