Distribution of the muscle spindles in human masticatory muscles / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the characteristics in the topographic distribution of the muscle spindles in human masticatory muscles.</p><p><b>METHODS</b>The muscle spindles of the masticatory muscles on both sides of 3 human corpses fixed in formalin for more than 1 year were observed histologically and analyzed quantitatively using an image analysis system.</p><p><b>RESULTS</b>The mean muscle spindle density was 32.11/g in the masseter, significantly higher in the deep muscular fibers (70.76/g) with high proportion of spindle complexes than in the superficial layers of the muscle belly (P<0.05). The mean spindle density in the temporalis was 5.44/g, higher in the anterior portion (7.44/g) than in the posterior portion (3.78/g, P<0.01). The medial pterygoid had a mean spindle density of 4.43/g.</p><p><b>CONCLUSION</b>These results indicate a heterogeneous distribution of muscle spindles in the masticatory muscles with different morphologies or in different portions of the same muscle, depending on muscle fiber type and muscular architecture.</p>