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July2010 Vol.47 Issue:        3       (Supp.) Table of Contents
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Second Lumbrical Versus Abductor Pollicis Brevis Muscle’s Latency in Carpal Tunnel Syndrome Diagnosis

Hala R. El-Habashy1, Amal F. Ahmed2


Departments of Clinical NeurophysiologyUnit1, Faculty of Medicine;

Basic Science2, Faculty of Physical therapy; Cairo University; Egypt



Background: Carpal tunnel syndrome (CTS) is the most common compressive neuropathy in the upper extremity and it is responsible for sustained annual coasts to society  in both terms of lost productivity and the coasts of treatment, and in 16%-34% cases with classic symptoms the neurophysiology is negative. Objective: To determine the diagnostic utility of the Median Motor Distal Latency (MMDL) to the second lumbrical muscle to that of the Abductor Policies Bevis (APB) muscle in diagnosis of CTS. Methods: 30 wrists (21 males and 9 females) of 17 apparently healthy subjects with mean age of 28.4±7.7 years were recruited in the control group and 30 wrists (15 males and 15 females) of 18 patients with mean age of 34.03±11.3 years in the patient group. Median motor distal latencies to the APB and 2nd lumbrical muscles were measured. Results: Two cutoff points were determined for each test; mean + 1 SD and mean + 2SD. Sensitivity and specificity of the MMDL to APB were 63.33% and 90% respectively at the lower cutoff point and 50% and 100% at the higher one. As for MMDL to 2nd lumbrical its sensitivity and specificity were 66.66% and 96.66 % respectively at the lower cutoff point and 36.66% and 100% at the higher one. Conclusion: It is concluded that 1) The MMDL to the 2nd lumbrical muscle was more sensitive and specific than the MMDL of the APB at the lower cutoff point, 2) The MMDL to the 2nd lumbrical muscle was less sensitive (but still specific) than the MMDL of the APB at the higher cutoff point. [Egypt J Neurol Psychiat Neurosurg. 2010; 47(3): 477-482]


Key Words: CTS, Latency to the 2nd lumbrical muscle, median- ulnar comparative tests in CTS.


Correspondence to Hala R.Elhabashy, Clinical Neurophysiology Unit, Faculty of Medicine, Cairo University, Egypt.

Tel.:+20102330040. Email:

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