FIBER-TYPE COMPOSITION OF MORPHOLOGIC REGIONS IN THE MACAQUE MULTITENDONED FINGER MUSCLES

The extrinsic multitendoned finger muscles seem likely to contain dist inct neuromuscular compartments that can act as independent functional subdivisions serving different fingers. Little evidence of such subdi visions is available, however, Regional specialization of histochemica l fiber type composition has been described in a number of monotendone d muscles, and in some muscles different neuromuscular compartments ha ve been shown to have different fiber type proportions, Therefore, we examined the fiber type composition of morphologically defined regions in the macaque multitendoned finger muscles. Although some trends wer e noted, none of the five multitendoned finger muscles showed signific ant regional differences in fiber type composition, Nor were differenc es found between muscles of the flexor group or between muscles of the extensor group, Comparing flexors and extensors revealed a slightly b ut significantly lower proportion of type I fibers in the flexors, We conclude that unlike certain monotendoned wrist muscles (such as FCU), the multitendoned muscles that flex and extend macaque fingers have m inimal histochemical specialization.