SEVERAL recent histochemical studies of muscle spindles1-9 have demonstrated the relative activity of various enzymes and other components in the different types of intrafusal fibers. With a single exception consisting of a brief report6 these results were based on studies of subhuman species. Since species differences in histochemical reactions of intrafusal fibers have been documented,1,4,6,7 conclusions drawn from nonhuman studies may be misleading when attempts are made to extrapolate these results to human muscle.
The purpose of this report is to describe the histochemistry of the nonnervous portion of normal human muscle spindles and to compare the reactions of intrafusal fibers with those of extrafusal fibers.
Material and Methods
For obvious reasons muscle tissue suitable for histochemical investigation is difficult to obtain from humans with no evidence of muscle disease. Biopsy specimens used in this study were obtained from the patients described below for the reasons listed.
Spiro AJ, Beilin RL. Human Muscle Spindle Histochemistry. Arch Neurol. 1969;20(3):271–275. doi:10.1001/archneur.1969.00480090059009
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