Variations of the median nerve in the carpal canal

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Tountas-C-P. Bihrle-D-M. MacDonald-C-J. Bergman-R-A. Department of Family Medicine, University of Minnesota, Duluth. J-Hand-Surg-[Am]. 1987 Sep. 12(5 Pt 1). P 708-12. Eight hundred twenty-one median nerves were retrospectively and prospectively reviewed for variations during operations to treat carpal tunnel syndrome. Ninety-two cadaver median nerves were also dissected to document the incidence of variations within the carpal canal. The combined incidence of anomalies at operation (Lanz groups 1 to 4) was 9.8% and in the cadaver series 18%. The discrepancy reported by Poisel, 54% in the Lanz group 1 series, versus ours of 1.42% cannot be explained.