Semmes-Weinstein monofilaments

Calibrated nylon filaments that buckle at a known force, applied to the skin to measure the threshold of light-touch pressure perception. As a threshold test the monofilament changes early in nerve compression, before two-point discrimination, which makes it sensitive for carpal tunnel syndrome; its specificity depends on the filament chosen as the cut-off, and its inter-observer reliability is lower than that of other sensory tests.

Related terms

• Investigation

  Two-point discrimination

  The smallest distance at which two points touching the skin simultaneously are perceived as separate, tested statically or with the points moving, and used to grade discriminative sensation after nerve repair. Technique is poorly standardised and the cut-offs for excellent, good and poor results vary between authors, so comparisons between series are unreliable.

Articles mentioning this term

1. FESSH preparation · 26 September 2026

   Clinical examination of the hand and wrist

   Hand and wrist examination for FESSH candidates: how accurate the Phalen, Tinel, scratch collapse, Elson, Watson, grind, fovea and Allen tests really are.

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