Efferent and afferent innervations of Mueller's muscle related to involuntary contraction of the levator muscle: important for avoiding injury during eyelid surgery

The human superior tarsal muscle (Müller’s muscle): a morphological classification with surgical correlations

“…The STM has recently been proposed to have a physiological mechanoreceptor role, which would be useful in the correction of eyelid ptosis. Such a physiological role involves both an increase in the reflexive contraction of the levator muscle and a proportional reduction in the contraction of the frontalis muscle (Yuzuriha et al 2005(Yuzuriha et al , 2008. Upper eyelid ptosis commonly occurs due to abnormal functioning of either the LPSM or the STM.…”

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“…4 Mueller's muscle potentially acts like a serial kind of muscle spindle for the LPS muscle because it is doubly innervated by efferent unmyelinated sympathetic nerves as well as myelinated trigeminal proprioceptive afferents, both forming the transverse nerve that joins the lacrimal nerve. 5 The medial horn of the LPS aponeurosis lies close, blending with the reflected tendon of superior oblique muscle; in addition, superior oblique tendon damage from ptosis surgery is well recognized and may give rise to superior oblique palsy as well as Brown's syndrome. 6 Proprioceptive elevation of ptotic lid and reflex lacrimation have been described in congenital third cranial nerve palsy.…”

“…7 The LPS muscle, like the muscles of the jaw, is an antigravity muscle consisting of fatigable fast-twitch and fatigue-resistant slow-twitch muscle fibers. 5 Voluntary retraction of upper lid is maintained by contraction of the LPS muscle fast-twitch muscle fibers, whereas involuntary retraction against gravity is maintained by involuntary continuous contraction of slow-twitch muscle fibers as a result of proprioception evoked by mechanoreceptors in Mueller's muscle. 5 Short, inelastic tendons in Brown syndrome, unable to relax in adduction, may stretch proprioceptive structures in the adjoining Mueller's muscle, resulting in reflex elevation of upper eyelid by activation of slow-twitch, fatigueresistant multiply innervated fibers in the LPS muscle, quite like the monosynaptic Hoffmann reflex.…”

“…5 Voluntary retraction of upper lid is maintained by contraction of the LPS muscle fast-twitch muscle fibers, whereas involuntary retraction against gravity is maintained by involuntary continuous contraction of slow-twitch muscle fibers as a result of proprioception evoked by mechanoreceptors in Mueller's muscle. 5 Short, inelastic tendons in Brown syndrome, unable to relax in adduction, may stretch proprioceptive structures in the adjoining Mueller's muscle, resulting in reflex elevation of upper eyelid by activation of slow-twitch, fatigueresistant multiply innervated fibers in the LPS muscle, quite like the monosynaptic Hoffmann reflex. Because taxonomy influences understanding, it may be appropriate to address this phenomenon as a superior oblique tendonMueller's muscle proprioceptive reflex.…”

Pathogenesis and Surgical Correction of Involuntary Contraction of the Occipitofrontalis Muscle That Causes Forehead Wrinkles

“…Because the levator muscle lacks interior muscle spindles, despite being an antigravity mixed muscle, Mueller smooth muscle functions as a serial kind of muscle spindle of the levator muscle. [3][4][5] Mueller muscle is located serially to the levator muscle and is innervated by not only the sympathetic efferent nerve but also the trigeminal proprioceptive afferent nerve. 5 The axons of the trigeminal proprioceptive nerve, which are attached to the intermuscular connective tissues among the Mueller smooth muscle fibers, function as the mechanoreceptor in the same manner as the periodontal mechanoreceptor.…”