Orbital Approach for Retrieval of Transected Extraocular Muscles

Transection of an extraocular muscle can occur from orbital and facial trauma, or as a complication of surgery. The injury can occur either near the muscle insertion or in the muscle belly. Identification of the proximal end of the muscle in the orbit may be difficult, especially if the transection occurs a farther distance from the insertion, and, in these cases, the muscle is often considered lost. We present two patients who suffered from traumatic transections of an extraocular muscle more than 10 mm from the insertion. Both patients underwent transconjunctival orbitotomy to retrieve and secure the severed extraocular muscle. Both patients achieved good primary gaze alignment postoperatively. Preoperative imaging should be considered in cases of traumatic extraocular muscle transection.     

Brainstem terminations of extraocular muscle primary afferent neurons in the monkey

The central terminations of afferent nerve fibers from the extraocular muscles of the monkey were investigated by means of transganglionic transport of wheat germ agglutinin-conjugated horseradish peroxidase (WGA/HRP). Following injections of selected extraocular muscles with WGA/HRP, terminal labeling was apparent in the ipsilateral trigeminal sensory and cuneate nuclei. The density of trigeminal projections varied markedly from one rostrocaudal level to the next, being heaviest within the ventrolateral portion of pars interpolaris of the spinal trigeminal nucleus. A second extraocular muscle afferent representation was noted in ventrolateral portions of the cuneate nucleus. This projection was restricted to rostral portions of pars triangularis of the cuneate nucleus, partially overlapping the afferent termination from dorsal neck muscles. It is likely that some of the problems encountered in formulating conclusions regarding the functional role of extraocular muscle proprioception are due to a lack of detailed information of the central termination pattern of muscle afferents. Taken together, the present findings should provide a basis for further anatomical and physiological studies designed to elucidate the role played by extraocular muscle proprioceptors in vision and oculomotor control.     

Extraocular muscle dystonia due to acquired (non‐Wilsonian) hepatocerebral degeneration

We present a video report of a patient with advanced non‐Wilsonian cirrhotic liver disease who developed extraocular muscle dystonia (oculogyric crisis) and severe orofaciolingual dyskinesias. Acquired hepatocerebral degeneration causes choreic movements, especially of cranial muscles, but dystonic ocular spasm is an infrequent manifestation of this disorder. This case illustrates that AHD should be considered in the differential diagnosis of extraocular muscle dystonia. © 2008 Movement Disorder Society     

定量眼眶冠状位CT测量在甲状腺相关眼病中的应用

目的 探讨定量冠状位CT检查在Graves眼病诊断中的应用价值.方法 分别测量50例正常者和50例Graves眼病者的眼外肌的最大截面积、短径和长径,并计算每条眼外肌的R值.结果 50例Graves眼病患者,共228条眼外肌增粗,以下直肌(30.3%)和内直肌(23.2%)最常见,其次为上直肌(19.7%),外直肌(13.6%)和上斜肌(13.4%),其平均最大截面积(70.21 mm2、56.93 mm2、64.06 mm2、58.51 mm2、20.65 mm2)和R值(0.61、0.55、0.61、0.50、0.52)明显大于正常组的平均最大截面积(27.72 mm2、 27.07 mm2、26.93 mm2、36.74 mm2、9.42 mm2)和R值(0.41、0.35、0.60、0.34、0.44),Graves组和正常组之间差异有统计学意义(P＜0.01).结论 定量冠状位CT检查特别是R值的测量可以准确判断眼外肌的增厚,有助于Graves眼病的诊断.     

Cross‐disease comparison of amyotrophic lateral sclerosis and spinal muscular atrophy reveals conservation of selective vulnerability but differential neuromuscular junction pathology

Neuromuscular junctions are primary pathological targets in the lethal motor neuron diseases spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS). Synaptic pathology and denervation of target muscle fibers has been reported prior to the appearance of clinical symptoms in mouse models of both diseases, suggesting that neuromuscular junctions are highly vulnerable from the very early stages, and are a key target for therapeutic intervention. Here we examined neuromuscular pathology longitudinally in three clinically relevant muscle groups in mouse models of ALS and SMA in order to assess their relative vulnerabilities. We show for the first time that neuromuscular junctions of the extraocular muscles (responsible for the control of eye movement) were resistant to degeneration in endstage SMA mice, as well as in late symptomatic ALS mice. Tongue muscle neuromuscular junctions were also spared in both animal models. Conversely, neuromuscular junctions of the lumbrical muscles of the hind‐paw were vulnerable in both SMA and ALS, with a loss of neuronal innervation and shrinkage of motor endplates in both diseases. Thus, the pattern of selective vulnerability was conserved across these two models of motor neuron disease. However, the first evidence of neuromuscular pathology occurred at different timepoints of disease progression, with much earlier evidence of presynaptic involvement in ALS, progressing to changes on the postsynaptic side. Conversely, in SMA changes appeared concomitantly at the neuromuscular junction, suggesting that mechanisms of neuromuscular disruption are distinct in these diseases. J. Comp. Neurol. 524:1424–1442, 2016. © 2015 The Authors The Journal of Comparative Neurology Published by Wiley Periodicals, Inc.     

Familial unilateral Brown syndrome

Purpose: To report a family in which three siblings have unilateral late-onset Brown syndrome. Methods: The entire nuclear family underwent ophthalmologic evaluation. Orbital imaging and systemic workup were obtained to rule out local or systemic causes. Historic information was obtained from unavailable family members. The family's Brown syndrome trait was analyzed for linkage to the known congenital fibrosis syndrome loci and the CFEOM2 gene, ARIX , was sequenced in affected individuals. Results: All affected siblings developed left-sided Brown syndrome, worse on awakening, at 12–13 years of age. No evidence of Brown syndrome could be identified in other family members, either by exam or history. No abnormalities of the trochlear-tendon complex could be documented. Haplotype analysis of the Brown syndrome phenotype was consistent with recessive inheritance at the DURSI locus and dominant inheritance with reduced penetrance at the DURSI, DURS2, and FEOMI loci. No mutations were detected in CFEOM2 gene, ARIX . Conclusions: We propose that a genetically determined predisposition to Brown syndrome is likely responsible for the observed manifestations in this family and that late age of onset and intermittent manifestations do not distinguish acquired from hereditary Brown syndrome. The pattern of inheritance of the Brown phenotype in this family could be either autosomal recessive or autosomal dominant with reduced penetrance. Our analysis only permitted the exclusion of the FEOM3 locus and the FEOM2 gene, ARIX . Future genetic studies of additional Brown syndrome families should shed additional light on the genetic basis of this disorder.     

Immunohistochemical Study of Fiber Types in Human Extraocular Muscles

Fiber types in human extraocular muscle (h-EOM) were examined immunohistochemicaliy with antibodies against slow tonic (anti-ALD) and slow twitch (anti-SOL) myosins. Four types of muscle fiber in h EOM were distinguishable according to their reactivities with these antibodies. Groups 1 and 2 fibers reacted with both antibodies, group 1 fibers showing stronger reactivity than group 2 fibers with anti-ALD. Group 3 fibers reacted only with anti-SOL. Group 4 fibers did not react with either antibody. The latter were the most common, and were the main fibers in both the peripheral (outer orbital) and central zones of h EOM. The next most common were group 1 fibers, which were located mainly in the peripheral layer. Group 2 fibers were less common, but were the second most common type in the central layer. Group 3 fibers were only minor constituents. Multiple innervations were observed in some fibers of groups 1 and 2, and group 1 fibers were suggested to be slow tonic myofibers in h-EOM. These specific immunohistochemical and physiological features of h-EOM seem to be the basis of the low morbidity seen in the usual types of muscular dystrophy. Acta Pathol Jpn 40: 808-814, 1990.