Muscle spindle distribution in the levator veli palatini muscle in the rat.

We previously reported that the levator veli palatini muscle (LVP) in the rat is innervated by the glossopharyngeal nerve. The LVP positioned between the mouth and nasopharynx, has important roles in respiration, swallowing, and speech. Muscle spindles, structures scattered through skeletal muscles, appear to function like miniature strain gauges, sensing the degree of tension in the muscle. Muscle spindles were demonstrated in the rat's LVP in our neurophysiologic and histologic studies. We think the stretch of LVP modulates the rapid movements of the LVP by the proprioceptive component of the muscle spindle. Our results infer it is important to protect the innervation and the muscle spindles of the LVP from damage during any surgical dissection of the soft palate musculature.