Monofilament estimation of pressure sensation

Use of the monofilament pressure esthesiometer for quantitative assessment of the cutaneous pressure perception threshold in the foot. The filament (arrow) is placed at a right angle to the skin on the plantar surface of the foot; pressure is then gradually increased until the filament buckles, indicating that a known amount of pressure (determined by the stiffness of the filament) has been applied. The patient is asked if the pressure has been felt. Diabetic patients with insensitivity to the monofilament are at increased risk for foot ulcers.