A Comparative Study Of The Synovial Muscles And The Intramuscular Muscles

OBJECTIVE:To study the synchronous electromyograhic characteristics of infrahyoid muscles [sternohyoid muscle (SH), sternothyoid muscle (ST) and thyrohyoid muscle (TH)] and intrinsic laryngeal muscles [lateral cricoarytenoid muscle (LCA) and posterior cricoarytenoid muscle (PCA)].METHODS:Uunder general anesthesia, synchronous electromyograhic features of9dogs were contrasted during repiration, swallowing and phonation. The amplitude and duration of motor unit potentials (MUPs), the maximum amplitude and persistent time of motor unit recruitments, the synchronicity of intrinsic and external laryngeal muscles of various states were analysed.RESULTS:?The SH, ST and PCA discharged during inspiratory phase, but, the amplitude of the MUPs and recruitments of ST and SH are smaller than the PCA's.?Iin the staus of phanation and swallowing, the activities of the PCA are inhibitated with the smaller amplitude of MUPs and recruitments than the SH's and SH's.?The TH and PCA firing during expiration. Except the amplitude of MUPs and recruitments of forced respiration, no significant differences are reached between them.?During phnation and swallowing, the myoelectic parameters of TH and LCA are similar with no significant differences but the amplitude of the MUPs and recruitments.CONCLUSION:?Not only TH synchronously discharge with LCA during expiration, but also has similar myoelectric parameters. TH may be the optional muscles to reconstruct of the vocal cord adduct function.?Though the ST, SH synchronously discharge with PCA during inpiration, myoelectric parameters are significantly difference between ST, SH and PCA. The ST, SH may not the ideal muscle to reestablish the vocal cord abduct function.