The Proprioception in the Muscles Supplied by the Facial Nerve

Abstract

Proprioception is a quality of somatosensibility that informs the central nervous system about the static and dynamics of muscles and joints. In muscles, the proprioceptive originates in the specialized sensory-organ-denominated muscle spindles. Nevertheless, facial muscles lack muscle spindles, but the facial proprioception plays key roles in the regulation and coordination of facial musculature and diverse reflexes. At the basis of these functional characteristics are the multiple communications between the facial and the trigeminal nerves, and neuroanatomical studies have demonstrated that facial proprioceptive impulses are conveyed via branches of the trigeminal nerve to the central nervous system. Substituting muscle spindles facial muscles contain other kinds of proprioceptors of variable morphology that display immunoreactivity for some putative mechanoproteins known to participate in proprioception (acid-sensing ion channel 2, transient receptor potential vanilloid 4, and Piezo2).