Online ISSN: 2515-8260

A Study to Analyse of Shape, Amplitude of CMAP of Both Median and Ulnar Nerves and Analysis of Anatomical Innervations of Small Muscles of Hand.

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Dr. Vikas Kumar1

Abstract

Aim: the aim of this study was to analyze shape, amplitude of CMAP of both median and ulnar in normal population and to analyze the anatomical innervations of small muscles of hand in normal cadavers. Material and methods: This was retrospective observational study Department of Physical Medicine and Rehabilitation Anugrah Narayan Magadh Medical College, Gaya, India for one year. 200 normal subjects (60 males and 140 females) were include in this study. Motor conduction studies of both median and ulnar nerves were done for the included subjects. Nehon Coden machine wasused to conduct the tests. Analysis of the shape of CMAP, amplitude and distal latency were performed. Results: 70 percent of the studied subjects were females, while male constituted only 30% with significant difference between both sexes. The mean age of the studied subjects was 38.21 ± 9.1 (age range 18-70). The mean amplitude of median nerve (12.34 mv) was significantly higher than that of the ulnar nerve (11.12 mv) .The mean DL of the median nerve (3.42 msec) was significantly longer than that of the ulnar nerve (2.75 msec). The median nerve CMAP was mostly dome shaped, rather than double peaked. Whereas CMAP of the ulnar was more frequently non dome i.e double peaked, rather than dome shaped. There were no statistical significant differences between the amplitude of dome shaped CMAP and double peaked CMAP in either median or ulnar nerves. The APB received nerve supply from the median nerve in 87% of the specimens and double innervations from both median and ulnar nerves in 13% of the specimens. Flexor pollicis brevis (FPB) received nerve supply from the median nerve alone in 42% of the specimens and from the ulnar nerve alone in 11% of the specimens. FBP received innervations from both nerves median and ulnar in 47% of specimens. Abductor digiti minimi (ADM) muscle received one branch from deep branch of the ulnar nerve in 88% of the specimens and from superficial branches of the ulnar nerve in 12% of the specimens. Conclusion: The configuration of the CMAP of the median nerve is mostly dome, whereas that of the ulnar is mostly double peaked. Variability in the pattern of innervations of the small muscle of the hand could be a possible etiological factor.

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