Efferent and afferent innervations of Mueller's muscle related to involuntary contraction of the levator muscle: important for avoiding injury during eyelid surgery  Shunsuke Yuzuriha, Kiyoshi Matsuo, Yoshimasa Ishigaki, Niroh Kikuchi, Kyutaro Kawagishi, Tetsuji Moriizumi  British Journal of Plastic Surgery  Volume 58, Issue 1, Pages 42-52 (January 2005) DOI: 10.1016/j.bjps.2004.06.006

Figure 1 Innervations of the levator muscle and Mueller's muscle. (A) Classical innervations induce voluntary contraction of the levator muscle and sympathetic contraction of Mueller's muscle. (B) Hypothetical innervations not only induce voluntary contraction of the levator muscle and sympathetic contraction of Mueller's muscle but also induce involuntary contraction of the levator muscle as a continuous stretch reflex. III, oculomotor nuclear complex; CCN, central caudal nucleus of the oculomotor nuclear complex; F, fast-twitch muscle fibres; S, slow-twitch muscle fibres; I-a, I-a nerve fibre; mesV, mesencephalic trigeminal nucleus; NCSC, noncardiovascular sympathetic center; CSC of Budge, ciliospinal center of Budge; SCG, superior cervical ganglion. British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)

Figure 2 Temporary and permanent injuries to the innervations related to involuntary contraction of the levator muscle. (A, B) Left temporary severe blepharoptosis due to local injection of lidocaine into the bilateral eyelids. (C, D) Left temporary moderate blepharoptosis. (E, F) Left temporary mild blepharoptosis. (G, H) Permanent severe blepharoptosis after Mueller muscle-conjunctival resection for acquired blepharoptosis in the left eyelid. The left levator muscle belly shows fatty degeneration. (I, J) Permanent severe blepharoptosis after resection of the distal levator muscle with Mueller's muscle for acquired blepharoptosis in the left eyelid. Scar tissue remains in the relevant area of the left eyelid. British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)

Figure 3 Histological sections of Mueller's muscle and its surrounding tissues. (A) The entire Mueller's muscle from its insertion into the tarsus to the portion interdigitating with the levator muscle is divided into six equal segments, I to VI (Azan stain). T indicates tarsus; LM, levator muscle; SRM, superior rectus muscle. (B) Some neural structures positive for the S-100 protein (arrows) follow a zigzag longitudinal course along a fine arterial and venous arcade (S-100 stain). M indicates Mueller's muscle; LA, levator aponeurosis; V, vein. (One graduation on the ruler=0.01 mm) (C) A fine neural structure positive for the S-100 protein (arrow) is found only in Mueller's smooth muscle fibre at the undulating portion interdigitating between Mueller's muscle and the levator muscle (S-100 stain). (D) Schwann cells in two proprioceptive receptors of the superior rectus muscle (S-100 stain). (E) A thin nerve bundle (arrow) is accompanied by the peripheral arteriovenous arcade in segment I (Azan stain). A indicates artery; T, tarsus. (F) Thick nerve bundles (arrows) are associated with another arteriovenous arcade in segment VI (Azan stain). (G) Cross-sections of a nerve just before it enters into the lacrimal gland appears positive for the S-100 protein (left) and negative for tyrosine hydroxylase (right). (H) Cross-sections of other nerves just before they enter into the lacrimal gland appear positive for both the S-100 protein (left) and tyrosine hydroxylase (right). British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)

Figure 4 (A) Distribution of the numbers of nerve bundles in the six segments. (B) Distribution of the diameters of nerve bundles in the six segments. British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)

Figure 5 Gross anatomy of the innervations of Mueller's muscle. A fine transverse nerve that is accompanied by the peripheral arcade (arrow), and other nerves that run between the distal portion of the levator muscle and the proximal portion of Mueller's muscle (arrow heads) pass through the lacrimal gland to join the lacrimal nerve. T indicates tarsus; M, Mueller's muscle; L, levator muscle; LH, lateral horn (turned up); PF, preaponeurotic fat; LG, lacrimal gland; SON, supra-orbital nerve; LN, lacrimal nerve; ZFN, zygomatico-facial nerve. British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)

Figure 6 Cross-sectional and perspective views of hypothetical innervations of Mueller's muscle Triangles (▿) indicate the points of electrical stimulation applied to the thick transverse nerve on the proximal portion of Mueller's muscle or the thin transverse nerve along the peripheral arteriovenous arcade. Afferent, trigeminal proprioceptive afferent nerve; Efferent, unmyelinated sympathetic efferent nerve; Thick, thick transverse nerve fibres on the levator muscle; Thin, thin transverse nerve fibres with an arteriovenous peripheral arcade; Ia, Ia nerve fibre; I, type I muscle fibre; II, type II muscle fibre; CCN, caudal central nucleus of the oculomotor nuclear complex; mesV, mesencephalic trigeminal nucleus; NCSC, noncardiovascular sympathetic center; CSC of Budge, ciliospinal center of Budge; SCG, superior cervical ganglion. British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)

Figure 7 Positive retraction of the contralateral upper eyelid as a result of Mueller's muscle. (A) Electrical stimulation of the thick transverse nerve fibres induces retraction of the contralateral upper eyelid. (B) Stretching of Mueller's muscle induces retraction of the contralateral upper eyelid. (C) After correction of the aponeurotic blepharoptosis, electrical stimulation of the thick transverse nerve fibres induces greater retraction of the contralateral upper eyelid. (D) Following the removal of forceps placed to prevent contraction of the levator muscle, electrical stimulation of the thick transverse nerve fibres induces greater retraction of the bilateral upper eyelids. (E) In another case, before correction of the aponeurotic blepharoptosis, stretching of Mueller's muscle induces retraction of the contralateral upper eyelid. (F) After the correction, the integrity of the trigeminal proprioceptive afferent pathway is verified by electrical stimulation of the thick transverse nerve fibres. British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)

Figure 8 Contraction of Mueller's muscle by electrical stimulation of the thick transverse nerve fibres. (A) Horner's syndrome apparent on the left side. (B) A forceps-type nerve stimulator is placed on the thick transverse nerve fibres. (C) Electrical stimulation prolongs retraction of the ipsilateral upper eyelid. (D) A lag of the stimulated upper eyelid is apparent upon closing. British Journal of Plastic Surgery 2005 58, 42-52DOI: (10.1016/j.bjps.2004.06.006)