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Sensitivity of three median‐to‐ulnar comparative tests in diagnosis of mild carpal tunnel syndrome
Author(s) -
Uncini Antonino,
Dimuzio A.,
Awad J.,
Manente G.,
Tafuro M.,
Gambi D.
Publication year - 1993
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.880161215
Subject(s) - carpal tunnel syndrome , medicine , median nerve , sensitivity (control systems) , carpal tunnel , wrist , surgery , nuclear medicine , engineering , electronic engineering
We studied 193 hands of 113 patients referred for typical carpal tunnel syndrome (CTS). Ninety‐five (49%) hands had normal median distal motor latency (≤4.2 ms) and normal or borderline sensory conduction velocity from digit 2 stimulation (≥45 m/s). In these cases we performed three median to ulnar comparative tests: (1) difference between median and ulnar distal motor latencies recorded from the second lumbrical and interossei muscles (2L‐INT); (2) difference between median and ulnar sensory latencies from digit 4 stimulation (D4M‐D4U); and (3) difference between median and ulnar mixed nerve latencies from palmar stimulation (PM‐PU). The 2L‐INT difference was ≥0.6 ms in 10% of hands. PM‐PU and D4M‐D4U were ≥0.5 ms in 56% and 77% of hands, respectively. The greater sensitivity of D4M‐D4U might be explained by the funicular topography and consequent greater susceptibility to compression of the cutaneous fibers from the third interspace which, at the distal carpal tunnel, are clumped superficially in the anteroulnar portion of the median nerve just beneath the transverse ligament. © 1993 John Wiley & Sons, Inc.