Fibrosis congénita de los músculos extraoculares / Congenital Fibrosis of Extraocular Muscles

La fibrosis congénita de los músculos extraoculares se caracteriza por una oftalmoplejía externa congénita, no progresiva, generalmente bilateral, con ptosis y alteración de los movimientos oculares. Existen varios tipos en dependencia del gen afectado y puede estar acompañada de hallazgos adicionales tanto oculares como generales. Para el manejo de los casos se realiza cirugía de la ptosis, alineación ocular y corrección del torticolis, además de su corrección óptica y rehabilitación para maximizar el resultado visual. Con el objetivo de estar al día sobre esta enfermedad se realiza una revisión de las publicaciones de los últimos cinco años en este tema. Actualmente no hay tratamientos que puedan restaurar la funcionalidad completa y el rango de movimiento de los músculos extraoculares, pero mejorar su funcionalidad visual es primordial(AU)

Congenital fibrosis of the extraocular muscles is characterized by congenital external ophthalmoplegia, nonprogressive, usually bilateral, with ptosis and altered eye movements. There are several types depending on the affected gene and it may be accompanied by additional ocular or general findings. For the management of these cases, ptosis surgery, ocular alignment and torticollis correction are performed, as well as optical correction and rehabilitation to maximize visual outcome. In order to be updated about this disease, a review of the publications on this subject within the last five years is carried out. Currently, there are no treatments that can restore full functionality and range of motion of the extraocular muscles, but improving their visual functionality is paramount(AU)

Overall distribution pattern of the intramuscular nerves of the extraocular muscles and its clinical implications / Patrón de distribución general de los nervios intramusculares de los músculos extraoculares y sus implicaciones clínicas

SUMMARY: The purpose of this study was to reveal the overall distribution pattern of the intramuscular nerves of each extraocular muscle and provide morphological guidance for the selection of the neuromuscular compartment during extraocular muscle transplantation and target localization of the botulinum toxin A injection to correct strabismus. We studied 12 Chinese head specimens that were fixed with formalin. The extraocular muscles from both sides of each head were removed, and a modified Sihler's staining technique was used to reveal the overall distribution pattern of the intramuscular nerves. We observed an intramuscular nerve-dense region formed by the intramuscular arborized branches in the semitransparent superior rectus, inferior rectus, medial rectus, lateral rectus, superior oblique, inferior oblique, and levator palpebrae superioris muscles with Sihler's staining technique. The seven extraocular muscles can each be divided into two neuromuscular compartments. The intramuscular nerve-dense regions of the superior, inferior, medial, and lateral rectus and the superior oblique, inferior oblique, and levator palpebrae superioris muscles were positioned at 33.50 % -72.72 %, 40.21 % - 66.79%, 37.92 % - 64.51 %, 31.69 % - 56.01 %, 26.35 % - 64.98 %, 40.46 % - 73.20 %, and 27.72 % - 66.07 % of the lengths of the muscle bellies, respectively, and the centers of intramuscular nerve dense regions were located at 59.50 %, 54.18 %, 51.68 %, 50.08 %, 48.38 %, 56.49 %, and 50.77 % of the length of each muscle belly, respectively. The aforementioned values are the means of the actual values. These results suggest that when the strabismus is corrected with muscle transplantation, the extraocular muscle should be transplanted based on the neuromuscular compartment, which would benefit the function of both donor and recipient muscles. The localization of these nerve dense regions is recommended as an optimal target for the injection of botulinum toxin A to treat strabismus.

RESUMEN: El objetivo de este estudio fue revelar el patrón de distribución de los nervios intramusculares de cada músculo extraocular y, proporcionar una guía morfológica para la selección del compartimento neuromuscular durante el trasplante de músculo extraocular, y la localización de la inyección de toxina botulínica A para corregir el estrabismo. Estudiamos 12 muestras de cabezas de individuos chinos fijadas en formalina. Se extrajeron los músculos extraoculares de ambos lados de cada cabeza y, se utilizó una técnica de tinción de Sihler modificada para revelar el patrón de distribución general de los nervios intramusculares. Observamos una región densa en nervios intramusculares formada por los ramos intramusculares en los músculos recto superior semitransparente, recto inferior, recto medial, recto lateral, oblicuo superior, oblicuo inferior y elevador del párpado superior con técnica de tinción de Sihler. Los siete músculos extraoculares se pueden dividir cada uno en dos compartimentos neuromusculares. Las regiones intramusculares densamente nerviosas de los músculos recto superior, inferior, medial y lateral y los músculos oblicuo superior, oblicuo inferior y elevador del párpado superior se colocaron en 33,50 % -72,72 %, 40,21 % -66,79 %, 37,92 % -64,51 % , 31,69 % -56,01 %, 26,35 % -64,98 %, 40,46 % -73,20 % y 27,72 % -66,07 % de las longitudes de los vientres musculares, respectivamente, y los centros de las regiones densamente nerviosas intramusculares se ubicaron en 59,50 %, 54,18 % , 51,68 %, 50,08 %, 48,38 %, 56,49 % y 50,77 % de la longitud de cada vientre muscular, respectivamente. Los valores antes mencionados son medios de los valores reales. Estos resultados sugieren que cuando el estrabismo se corrige con trasplante de músculo, el músculo extraocular debe trasplantarse en función del compartimento neuromuscular, lo que beneficiaría la función tanto de los músculos donantes como receptores. Se recomienda la localización de estas regiones densas en nervios, como un objetivo óptimo para la inyección de toxina botulínica A para tratar el estrabismo.

Kimura's disease involving bilateral lacrimal glands and extraocular muscles along with ipsilateral face: A unique case report

A 23 year female presented with bilateral recurrent swelling of eyelids along with ptosis and proptosis for last 3 years. She also had swellings over the right cheek, parotid gland, and retro auricular area along with regional lymphadenopathy. Systemic laboratory workup revealed raised serum IgE and a high peripheral eosinophil count. Computed tomography and magnetic resonance imaging showed bilateral enlargement of extraocular muscles, lacrimal glands, and ipsilateral parotid gland. Excision biopsy of the retro-auricular lymph node was suggestive of Kimura's disease (KD). The patient responded well to systemic corticosteroid. KD rarely affects orbit, but it should be included in the differential diagnosis of inflammatory diseases of the orbit. To our knowledge, this is the first reported case of KD from India involving the orbit, lacrimal gland, extraocular muscles, parotid gland and buccal area.

Inestabilidad de la polea como causa de estrabismo / Pulley instability as a cause of strabismus

RESUMEN La caracterización de las poleas de los músculos extraoculares ha sido de gran trascendencia en la fisiopatología del equilibrio óculo-motor. El efecto mecánico de la polea funcional es cambiar el eje de acción del músculo de acuerdo con la orientación que el globo ocular presente. Los trastornos en la localización o estabilidad de las poleas pueden crear patrones de estrabismo incomitante. Es importante el conocimiento de estas anomalías porque los procedimientos quirúrgicos estándar no corrigen los desplazamientos de las poleas. Se realizó una búsqueda del tema de los últimos 10 años utilizando la plataforma de infomed(AU)

ABSTRACT Characterization of extraocular muscle pulleys has had great relevance in the physiopathology of ocular motor balance. The mechanical effect of the functional pulley is to change the axis of action of the muscle in keeping with the orientation of the eyeball. Pulley location or stability disorders may create incomitant strabismus patterns. It is important to be aware of these anomalies because standard surgical procedures do not correct pulley displacement. A search was conducted on the Infomed platform of papers published about the topic in the past ten years(AU)

Computed tomography imaging-based normative orbital measurement in Indian population

Purpose: This study aims to evaluate normal orbital structures with nonenhanced computed tomography (NCCT) and determine normative data for the Indian population. Methods: CT images of the orbits of 100 patients were retrospectively reviewed on a work station to record the normative data of the orbits. Clinical details of all patients were reviewed to ensure that they did not have ocular/orbital diseases. Both axial and coronal images were utilized to record the data. Results: The mean age of the population evaluated was 34.07 years, with male to female ratio of 1.77. The average orbital index for the left orbit was 97 and for the right side was 103. The mean thickness of left inferior rectus, lateral rectus, medial rectus, and the superior rectus was 3.36 mm, 3.14 mm, 3.80 mm, and 3.75 mm, respectively. The right inferior rectus, lateral rectus, medial rectus, and the superior rectus measured 3.46 mm, 3.14 mm, 3.83 mm, and 3.78 mm, respectively. The optic nerve sheath complex diameter varied between 3.05 mm and 7.17 mm for the left eye and 3.05 mm and 7.0 mm for the right eye. Conclusion: The study provides normative data on various orbital structures in an Indian population. This data is likely to be useful for diagnosing various orbital pathologies and in planning surgical orbital procedures.

Effects of Orbital Decompression on Lamina Cribrosa Depth in Patients with Graves' Orbitopathy

PURPOSE: We sought to investigate the effects of Graves' orbitopathy (GO) and orbital decompression on lamina cribrosa depth (LCD) using spectral-domain optical coherence tomography. METHODS: Forty eyes that underwent orbital decompression to relieve compressive optic neuropathy or correct disfiguring exophthalmos in the context of GO were included. Subjects were imaged with spectral-domain optical coherence tomography before surgery and at 1 and 3 months after surgery, at which the examiner measured the LCD (distance from the anterior surface of the lamina cribrosa to the Bruch membrane opening line) and peripapillary retinal nerve fiber layer thickness. Subjects were divided into two groups—a muscle-dominant group composed of patients who had extraocular muscle enlargement on preoperative orbital computed tomography scan and a fat-dominant group composed of patients who did not show extraocular muscle enlargement on preoperative orbital computed tomography scan—and subgroup analysis was performed. Preoperative and postoperative intraocular pressure, exophthalmos, LCD, and retinal nerve fiber layer thickness were evaluated. RESULTS: At baseline, LCD was remarkably shallower in the muscle-dominant group than in the fat-dominant group (95% confidence interval, p = 0.007). In the muscle-dominant group, LCD showed no definite change after surgery. However, the fat-dominant group showed temporary posterior displacement of the lamina cribrosa at 1-month postoperation that was reversed to baseline at 3 months postoperation (95% confidence interval, p < 0.01). CONCLUSIONS: The lamina cribrosa was anteriorly displaced preoperatively, and its position was nearly unchanged after the surgery, especially in association with extraocular muscle enlargement. An enlarged extraocular muscle could reduce the pressure-relieving effect of orbital decompression around the scleral canal in patients with GO.

Imaging of Cranial Nerves III, IV, VI in Congenital Cranial Dysinnervation Disorders

Congenital cranial dysinnervation disorders are a group of diseases caused by abnormal development of cranial nerve nuclei or their axonal connections, resulting in aberrant innervation of the ocular and facial musculature. Its diagnosis could be facilitated by the development of high resolution thin-section magnetic resonance imaging. The purpose of this review is to describe the method to visualize cranial nerves III, IV, and VI and to present the imaging findings of congenital cranial dysinnervation disorders including congenital oculomotor nerve palsy, congenital trochlear nerve palsy, Duane retraction syndrome, Möbius syndrome, congenital fibrosis of the extraocular muscles, synergistic divergence, and synergistic convergence.

A review: biomechanics of ocular tissue / 国际眼科杂志(Guoji Yanke Zazhi)

@#Biomechanics is the application of mechanics to biological systems. It helped to provide more understanding of normal tissue function, the effect of pathology, and the impact of treatment. The biomechanics research also is an important method to understand the prevention, onset and treatment of eye diseases. Eye ball is a closed globe which undergoes pressure from intraocular or extraocular. The pathology of eye will affect its biomechanics. Recent years, several methods about biomechanics were used to study eye diseases, such as corneal collagen crosslinking for treatment of keratoconus and corneal ectasia, posterior sclera reinforcement for treatment of pathological myopia, and so on. Here we reviewed the biomechanical research of extraocular muscle, cornea, sclera, iris and lens.

Hyperelastic analysis for the passive behavior of fox extraocular muscles in vitro / 医用生物力学

Objective To determine the hyperelastic parameters of shear modulus (μ) and curvature parameter (α) of extraocular muscles (EOMs) in Ogden hyperelastic model,so as to provide theoretical basis for clinical EOM surgery by numerical modeling.Methods The passive behavior of fox EOMs in vitro was determined by the uniaxial tensile test,and the hyperelastic analysis was conducted using the first-order Ogden model and ABAQUS software.Results The experimental result showed that the passive behavior of fox EOMs was nonlinear.The corresponding hyperelastic parameters μ =(6.57 ± 3.76) kPa and oα =8.16 ± 1.63 were obtained.When the strain of EOMs was larger than 6％,there were no statistical differences between the experimental result and the calculation result of the first-order Ogden hyperelastic model (P ＞ 0.05).Both the calculation result and the simulation result well fitted to the experimental result.Conclusions The hyperelastic parameters identified in this study can be used as the input for the corresponding numerical modeling of fox EOMs.

Genetic localization and clinical classification of congenital fibrosis of the extraocular muscles in 2 Chinese families / 眼科新进展

Objective To determine the pathogenic mutant gene and the classification for 2 Chinese families with congenital fibrosis of the extraocular muscles (CFEOM) by using candidate genes methods.Methyls All members in the 2 Chinese families with CFEOM were collected and underwent for clinical data collection,including medical history,physical examination and 5-8 mL peripheral venous blood for DNA extraction.Exon 2,8,20,21 of KIF21A,exon 1,2,3 of PHOX2A/ARIX,exon 1,2,3,and 4 of TUBB2B and exon 1,2,3,4 of TUBB3 were selected and synthesized by PCR,and the amplified samples were purified for sequences analysis by Chromas2.3 and DNAman7.0 software.Results There were 9 members developed CFEOM in family 1,with the typical CFEOM characteristics.The mutation site was located in KIF21A (exon 21),2860C ＞ T;and 4 patients in family 2 suffered this disease,and the typical CFEOM appearance features was in 3 patients.The mutation site was located in TBUU3 (exon 4),1249 G ＞ A.Conclusion The candidate genes methods can be used to identify the pathogenic genes of pedigrees with inherited diseases effectively.Family 1 belongs to CFEOM 1A type,which is the autosomal dominant inheritance with complete penetrance,and family 2 belongs to CFEOM 3A type,whivh is the autosomal dominant inheritance with incomplete penetrance.

Hyperelastic analysis for the passive behavior of fox extraocular muscles in vitro / 医用生物力学

Objective To determine the hyperelastic parameters of shear modulus (μ) and curvature parameter (α) of extraocular muscles (EOMs) in Ogden hyperelastic model,so as to provide theoretical basis for clinical EOM surgery by numerical modeling.Methods The passive behavior of fox EOMs in vitro was determined by the uniaxial tensile test,and the hyperelastic analysis was conducted using the first-order Ogden model and ABAQUS software.Results The experimental result showed that the passive behavior of fox EOMs was nonlinear.The corresponding hyperelastic parameters μ =(6.57 ± 3.76) kPa and oα =8.16 ± 1.63 were obtained.When the strain of EOMs was larger than 6％,there were no statistical differences between the experimental result and the calculation result of the first-order Ogden hyperelastic model (P ＞ 0.05).Both the calculation result and the simulation result well fitted to the experimental result.Conclusions The hyperelastic parameters identified in this study can be used as the input for the corresponding numerical modeling of fox EOMs.

Hyperelastic analysis for the passive behavior of fox extraocular muscles in vitro / 医用生物力学

Objective To determine the hyperelastic parameters of shear modulus (μ) and curvature parameter (α) of extraocular muscles (EOMs) in Ogden hyperelastic model,so as to provide theoretical basis for clinical EOM surgery by numerical modeling.Methods The passive behavior of fox EOMs in vitro was determined by the uniaxial tensile test,and the hyperelastic analysis was conducted using the first-order Ogden model and ABAQUS software.Results The experimental result showed that the passive behavior of fox EOMs was nonlinear.The corresponding hyperelastic parameters μ =(6.57 ± 3.76) kPa and oα =8.16 ± 1.63 were obtained.When the strain of EOMs was larger than 6％,there were no statistical differences between the experimental result and the calculation result of the first-order Ogden hyperelastic model (P ＞ 0.05).Both the calculation result and the simulation result well fitted to the experimental result.Conclusions The hyperelastic parameters identified in this study can be used as the input for the corresponding numerical modeling of fox EOMs.

Hyperelastic analysis for the passive behavior of fox extraocular muscles in vitro / 医用生物力学

Objective To determine the hyperelastic parameters shear modulus (μ) and curvature parameter (α) of extraocular muscles (EOMs) in Ogden hyperelastic model, so as to provide theoretical basis for clinical EOM surgery by numerical modeling. Methods The passive behavior of fox EOMs in vitro was determined by the uniaxial tensile test, and the hyperelastic analysis was conducted by the first-order Ogden model and ABAQUS software. Results The experimental result showed that the passive behavior of fox EOMs was nonlinear. The corresponding hyperelastic parameters μ =(6.57±3.76) kPa and α=8.16±1.63 were obtained. When the strain of EOMs was larger than 6%, there were no statistical differences between the experimental result and the calculation result of the first-order Ogden hyperelastic model (P>0.05). Both the calculation result and the simulation result well fitted to the experimental result. Conclusions The hyperelastic parameters identified in this study can be used as the input for the corresponding numerical modeling of fox EOMs.

Bilateral extraocular muscles enlargement from Kimura’s disease of the orbit.

Kimura’s disease (KD) is a rare chronic inflammatory disease of unclear etiology, characterized by subcutaneous nodules, mainly in the head and neck region, frequently associated with regional lymphadenopathy. Orbital involvement is infrequent and when it occurs, usually affects the eyelid or the lacrimal gland. We report a case of a 44-year-old man that presented with bilateral slowly progressive proptosis that was initially misdiagnosed as Graves’ Ophthalmopathy. 15 months of worsening proptosis and the development of facial and temporal swelling led to further investigation. Computed tomography and magnetic resonance imaging showed enlargement of all recti muscles and diffuse orbital infiltration. An orbital biopsy was performed and was consistent with the diagnosis of KD. Long term oral corticosteroid showed marked improvement of proptosis and facial swelling. This case serves to emphasize that KD should be included in the differential diagnosis of inflammatory diseases of the orbit, even when characterized by predominant involvement of the extraocular muscles.

Scleral Perforation During Inferior Rectus Muscle Recession in Congenital Fibrosis of the Extraocular Muscles

PURPOSE: We report a case of a scleral perforation during inferior rectus recession in congenital fibrosis of extraocular muscles and the management of this perforation with a scleral patch graft. CASE SUMMARY: A 20-month-old female with bilateral ptosis, absence of elevation and a chin-up position was diagnosed with congenital fibrosis of extraocular muscles. Because severe esotropia in the downward gaze was observed, we first performed esotropia surgery. After 1 year, she underwent a bilateral ptosis correction. We decided to perform bilateral inferior rectus recession due to an abnormal head posture and the absence of elevation. Because the inferior rectus muscles were extremely tight and adhered to the sclera, hooking and isolating these muscles during surgery was difficult. After muscle suture placement, a portion of the sclera that contacted the left inferior rectus was chipped off as this muscle was disinserted with blunt Westcott scissors. A scleral perforation was observed, thus, we placed a scleral patch graft using the donor sclera and finished the bilateral inferior rectus recession. No abnormal findings for the vitreous or retina were detected. At 8 months after surgery, the patient exhibited exotropia of 12 prism diopters in her primary gaze. Her abnormal head posture nearly disappeared. CONCLUSIONS: Careful isolation and disinsertion of the muscle from the globe is necessary in the treatment of patients who are expected to exhibit severe adhesions between the muscle and sclera, such as patients with congenital fibrosis of extraocular muscles.

Extraocular Muscles: Variation in Their Anatomy, Length and Cross-Sectional Diameter.

Background: The extraocular muscles (EOMs) bring about eye movement and studies exist which measure EOM length, cross-sectional diameter and volume. Knowledge of the normal values is crucial for determining when an EOM becomes pathological. The aim of this study was to dissect the orbit and measure the length and crosssectional diameter of the EOMs. Methods and Materials: Eighteen orbits from 9 formalin fixed cadavers (4 male, 5 female), age range 70-95, were dissected. The length of the EOM was measured with a digital caliper, the halfway point of the EOM found and the cross-sectional diameter measured. Length and cross-sectional diameter measurements from the left and right orbits were compared. The correlation between age and EOM length and age and EOM cross-sectional diameter was assessed. The association between gender and EOM length and gender and EOM was analysed. Any anatomical variation in the EOMs dissected would be noted. Results: Mean (±SD) lengths in numerical order were: levator palpebrae superioris, 42.8±4.6mm, superior oblique, 39.2±4.5mm, medial rectus, 38.5±3.1mm, lateral rectus, 38.4±2.4mm, superior rectus, 38.2±4.1mm, inferior rectus, 37.2±2.4mm and inferior oblique, 22.5±4.4mm. Mean (±SD) cross-sectional diameters in numerical order were: medial rectus, 7.9±1.2mm, lateral rectus, 6.7±1.4mm, superior rectus,6.5±1.3mm, inferior oblique, 6.5±0.9mm, inferior rectus, 6.2±0.9mm, levator palpebrae superioris, 6.0±1.1mm and superior oblique 4.3±1.1mm. There was no significant difference between left and right sides for length and cross-sectional diameter. There was also no association between age and length and age and cross-sectional diameter. There was no association between gender and length and gender and cross-sectional diameter. Conclusion: This study presents normative measurements for EOM length and cross-sectional diameter. One anatomical variation was found: a thin muscle belly passing medially and originating from the same point as the LPS. This is estimated to occur in 8-15% of cases. Although no anatomical variations in the rectus muscles were observed this is likely due to their much lower frequency.

EtioIogy anaIysis and surgery of paraIytic strabismus in aduIts / 国际眼科杂志(Guoji Yanke Zazhi)

·AlM: To investigate pathogeny and effects of surgery on paralytic strabismus. · METHODS: A retrospective study was done in 46 patients with paralytic strabismus who underwent squint correction in our hospital from June 2010 to June 2013. Among 26 horizontal strabismus, the cases of extra rectus palsy was 16, internal rectus palsy was 10.Among all20 vertical strabismus, the cases of superior oblique palsy, superior rectus palsy, inferior rectus palsy, double elevator palsy counted for 7, 8, 2 and 3, respectively. Pathogenesis: trauma was 19 cases, followed by 10 cases that the causes could not be identified.Nine was congen ital paralytic strabismus, 8 o ccurred after nose or brain surgery. The surgery methods included rectus muscle recession, rectus muscle resection, partial rectus muscle transposition, Jensen procedure, inferior oblique myectomy and anterior transposition of inferior oblique. Statistical software SPSS10.0 was used in chi-square test between two groups, while the situation of paralysis eye movements improved by two methods in the horizontal strabismus group was compared with t test. · RESULTS: Among all horizontal strabismus the rate of cure, improvement and inefficiency was 20 ( 77%) , 5 ( 19%) and 1 ( 4%) , respectively. Among vertical strabismus the ratio of cure, improvement and inefficiency was 15 (75%), 3 (15%) and 2 (10%).There was no significantly difference between the two groups ( P >0.05 ). The movements of paralytic eyes were improved. Two procedures used in horizontal strabismus, can improve paralysis eye movements were 3.76 ±0.91, 3.72 ±0.84mm, with no significant difference (P=0.93) statistically. · CONCLUSlON: Paralytic strabismus in adults had complicated conditions. Choosing different operation methods in treating paralytic strabismus according to the degree of paralysis can result in satisfactory cosmetically alignment of the eyes and modify head position and diplopia.

MRI demonstrates abnormalities of motor nerves and extraocular muscles in congenital fibrosis syndrome due to mutations in KIF21 A / 国际眼科杂志(Guoji Yanke Zazhi)

AIM:To observe the structural basis of ocular motility abnormalities in patients with congenital fibrosis of the extraocular muscles type Ⅰ ( CFEOM Ⅰ) due to missense mutations in the developmental kinesin KIF21A using high - resolution magnetic resonance imaging ( MRI) . METHODS: Totally 11 affected individuals reported KIF21A mutations were correlated with MRI studies demonstrating extraocular muscles ( EOMs ) size, location, contractility, and innervation. EOMs and the motor nerve in the orbits were imaged with T1 weighted in a triplanar scan using a dual-phased coils with 2. 0mm thick. Motor nerves were imaged at the brainstem using head coils and 3D-FIESTA with 0. 6-mm thick. RESULTS: Patients with CFEOM Ⅰ exhibited different degrees of hypoplasia of oculomotor nerve, the abducens nerve and the trochlear nerve were also affected, of which 8 cases of orbital section could see the signal of abnormal nerve dominated by oculomotor nerve to lateral rectus. The both sides of six EOMS in all patients exhibited variable atrophy and abnormal bright internal signal on T1 imaging, particularly severe for the superior rectus and levator muscles. CONCLUSION: High - resolution MRI can directly demonstrate pathology of motor nerves,affected EOMs, and ‘Pulley' hypoplasia caused by CFEOM Ⅰ due to mutations in KIF21A,and these findings suggest that the neuronal hypoplasia is the etiological factor of CFEOM.

A morphometric study of the extraocular muscles / Estudio morfométrico de los músculos extraoculares

Extraocular muscles are important references in strabismus surgery and in placement of intraorbital devices. We analyzed extraocular muscles morphometry and possible anatomical variances of 20 orbits. We report the length, width, and points of insertion of the extraocular muscles. No anatomical variations in length, width and points of insertion were found. With regard to the rectus muscles, it was found that the superior rectus and lateral rectus are the longest muscles and that the width difference between the superior and inferior rectus is greater than that between the medial and lateral rectus and that the point of insertion of the rectus muscles has a variable morphology. The superior oblique muscle was smaller in caliber than the inferior oblique, as consistent with previous anatomical studies. Knowledge of the detailed morphology of extraocular muscles is fundamental in strabismus surgery and represents a key factor for the innovation of surgical techniques and orbital procedures.

Los músculos extraoculares son importantes en la cirugía de estrabismo y en la colocación de dispositivos intraorbitarios. Analizamos la morfometría de los músculos extraoculares y las posibles variaciones anatómicas en 20 orbitas. No encontramos variantes en longitud, anchura y sitios de inserción. Los músculos rectos superior y lateral son los mas largos; la diferencia en longitud entre los músculos rectos superior e inferior es mayor a la diferencia en longitud entre los músculos rectos medial y lateral. El músculo oblicuo superior es mas pequeño en calibre que el músculo oblicuo inferior, lo que coincide con otros estudios anatómicos. El conocimiento detallado de la morfología de los músculos extraoculares es fundamental en la cirugía de estrabismo y representa un factor clave para la innovación de técnicas quirúrgicas y procedimientos en la cavidad orbitaria.