The free forearm flap is a reliable and versatile tool in head and nec
k reconstruction, However, the patency of the microvascular anastomosi
s is difficult to monitor when the flap is buried in the reconstructio
n of the esophagus or orbital floor. We used a portion of forearm musc
le on a branch of the radial artery and vein as a monitor flap. After
the free forearm flap transfer, the monitor muscle flap was placed ext
ernally through a small skin incision. Flap viability was assessed by
observing the color of the bleeding elicited from the muscle flap. Mon
itor muscle flaps are raised easily during elevation of the forearm fl
ap. This technique was used successfully in 5 patients, This monitorin
g method provides a simple and reliable assessment of viability when d
irect monitoring of the forearm flap is not possible.