The Oculomotor Nerve: Anatomy and Pathology.

The oculomotor nerve is the third cranial nerve, exiting the brainstem in the medial border of the cerebral peduncle, from where it crosses straight to the superior orbital fissure. It is a purely motor nerve responsible for the innervation of all the extraocular muscles, except the superior oblique and lateral rectus muscles. It also has parasympathetic pre-ganglionic fibers, responsible for the innervation of sphincter pupillae and ciliary muscles. Magnetic resonance imaging (MRI) is the best imaging exam to evaluate patients with clinical signs of third cranial nerve palsy. The oculomotor nerve can be affected by several diseases, such as congenital malformations, trauma, inflammatory or infectious diseases, vascular disorders, and neoplasms. This article aims to review the oculomotor nerve anatomy, discuss the best MRI techniques to evaluate each nerve segment, and demonstrate the imaging aspect of the diseases that most commonly affect it.

Congenital Multiple Ocular Motor Nerve Palsy Complicated by Splitting of the Lateral Rectus Muscle.

We report a case of congenital multiple ocular motor nerve palsy combined with splitting of the lateral rectus muscle (LR). A 59-year-old Japanese female was investigated for worsening esotropia after corrective surgery. She presented with left hypertropia (35Δ) and esotropia (45-50Δ). Orbital magnetic resonance imaging (MRI) showed reduced belly sizes in the superior rectus, inferior rectus, and superior oblique muscles and splitting of the LR, extending from the origin to the belly, in the left eye. Splitting of the LR belly was detected on MRI in a case of congenital multiple ocular motor nerve palsy.

Congenital Ocular Neuromyotonia with Partial Third Nerve Palsy.

PURPOSE: We report the first case of congenital ocular neuromyotonia (ONM) and the results of strabismus surgery for this patient's co-existing cranial nerve (CN) III palsy. PATIENTS AND METHOD: The patient presented at 18 months with strabismus that had reportedly been present since the time of birth. On exam, she had persistent exotropia (RXT) and hypertropia (RHT) with episodes of esotropia in the right eye that could be evoked by sustained left gaze. A diagnosis of ONM with partial CN III palsy was made. T1-weighted, T2-weighted, and fluid-attenuated inversion recovery magnetic resonance imaging failed to reveal intracranial pathology. RESULTS: Gaze induced intermittent esotropia resolved with carbamazepine. Surgery was performed to improve the patient's RXT and RHT. Post-operatively, the patient's RXT had improved from 12 to 15 prism diopters (∆) at near and 20∆ at a distance to 10∆ RXT at near with no horizontal deviation at distance. Her deviation has remained stable for 13 years, as has her neurological exam and good state of health. CONCLUSION: This case demonstrates that ONM may present congenitally and adds to the body of knowledge regarding surgical outcomes on concurrent CN palsies in these patients.

Congenital Third Nerve Palsy Associated With Midbrain Hypoplasia Due to Bilateral Segmental Internal Carotid Artery Agenesis.

A 15-year-old girl, diagnosed with a partial right third nerve palsy, was found to have bilateral internal carotid artery agenesis. Neuroimaging with 3D-constructive interference in steady state scanning identified the possible etiology of the third nerve palsy as midbrain hypoplasia.

Sutura de tração permanente para tratamento de paralisia congênita de III nervo / Permanent treatment suture for the treatment of congenital nerve palsy of III nerve

Resumo A paralisia do terceiro nervo craniano representa o estrabismo paralítico de tratamento mais complexo e desafiador. Os casos de paralisia completa III par incitam o uso de certas técnicas de cirurgia de estrabismo destinadas a manter o olho voltado para a posição primária do olhar (PPO). Entretanto, as possibilidades terapêuticas são limitadas e complexas e o tratamento cirúrgico tende a hipocorreção e recorrências frequentes a longo prazo.O envolvimento completo e congênito do terceiro nervo craniano requer cirurgias para a exotropia, hipotropia e ptose.Dentre as técnicas cirúrgicas já descritas, optou-se pela realização de uma modificação da técnica cirúrgica de recuo-ressecção, que deu-se em único tempo cirúrgico, sendo suficiente para alcançar o objetivo estético. Este trabalho relata o resultado positivoda manutenção de sutura de tração à carúncula para tratamento cirúrgico de estrabismo paralítico congênito de nervo oculomotor de longa data.

Abstract Paralysis of the third cranial nerve represents the most complex and challenging paralytic squint. The cases of complete III nerve paralysis encourages the use of certain strabismus surgery techniques in order to keep eye in primary position of gaze. However, the therapeutic possibilities are limited and complex and the surgical treatment tends to hypocorrection and frequent recurrences in the long term. Complete and congenital involvement of the third cranial nerve requires surgeries for exotropia, hypotropia and ptosis. Among the surgical techniques already described, we choose a modification of the surgical technique of recession-resection, which occurred in a single surgical time, being suffice to achieve aesthetic objective. This paper reports the positive result of the maintenance of caruncle traction suture as surgical treatment of congenital III nerve paralysis.

Transposition of Both Oblique Muscles Combined With Lateral Rectus Botulinum Toxin Injection and Globe Fixation Suture in the Treatment of Congenital Cranial Nerve III Palsy.

The authors report a new technique to treat complete cranial nerve III palsy. A 15-year-old girl underwent botulinum toxin injection into the lateral rectus muscle, nasal transposition of both the superior and inferior oblique muscles to the medial rectus insertion, and absorbable suture globe fixation to the nasal orbital periosteum. Six months postoperatively, her primary position eye deviation was within 12 prism diopters of orthotropia with limitation of ductions in all directions. [J Pediatr Ophthalmol Strabismus. 2017;54:e13-e17].

Congenital third nerve palsy with synergistic depression on attempted adduction and trigemino-oculomotor synkinesis: Underpinnings of a spectral dysinnervation disorder.

The authors describe a case of congenital partial pupil-sparing third cranial nerve palsy with absent adduction, synergistic depression of globe and widening of palpebral fissure on attempted adduction and synergistic elevation and adduction on mouth opening and sideways thrusting of jaw. The case illustrates trigemino-oculomotor synkinesis associated with congenital third nerve palsy. The possible mechanism of miswiring involving the medial longitudinal fasciculus and trigeminal nuclei is discussed. At least some cases of congenital third cranial nerve palsy may fall in the realm of congenital cranial dysinnervation disorders (CCDDs) sharing a much wider spectrum of presentation.

Congenital cranial dysinnervation disorder in a boy with congenital mirror movements.

"Mirror movements" are an axonal guidance disorder that consists of involuntary contralateral movements that mimic unilateral intentional ones, typically involving the fingers of the hand. They can be isolated or associated with conditions such as Klippel-Feil syndrome, Kallmann syndrome, or congenital hemiplegia. Isolated congenital mirror movements are sometimes caused by autosomal dominant mutation in the genes DCC or RAD51. At least 4 previously reported cases had strabismus, 3 with Moebius syndrome and 1 with Duane retraction syndrome. We report the case of a boy with an unusual incomitant strabismus consistent with orbital dysinnervation and suggest that for some patients with congenital mirror movements the neurological miswiring extends to the orbit, causing congenital cranial dysinnervation disorder.

Congenital oculomotor nerve palsy due to effects of carotid artery agenesis.

Isolated carotid artery agenesis is not generally recognized as a cause of congenital oculomotor nerve palsy. We report this rare association in 2 children and examine the underlying mechanism.

Septo-optic dysplasia plus: a case report.

BACKGROUND: Septo-optic dysplasia, also referred to as de Morsier syndrome, is a congenital condition characterized by classic triad features: midline brain abnormalities, optic nerve hypoplasia and pituitary endocrine dysfunction. Sometimes, other various malformations appear within syndrome. CASE PRESENTATION: An 11 and 1/2-year-old Caucasian Southeast European female patient with earlier established diagnoses of growth hormone deficiency, diabetes insipidus, seizures, mental retardation, optic nerve atrophy and right ptosis, was directed to us for consultative examination.The girl of short stature and low weight for her age had bilateral optic nerve hypoplasia, poor vision, nystagmus and right eye oculomotor palsy. Electroencephalogram revealed epileptic changes. Magnetic resonance imaging showed an empty sella syndrome, partial hypoplasia of corpus callosum, cavum of pellucid septum and diffuse polymicrogyria of the left temporal lobe. We found all elements of septo-optic dysplasia plus syndrome with right oculomotor nerve involvement. CONCLUSION: By earlier findings and evaluation, we established a diagnosis of septo-optic dysplasia plus. The case confirms the existence of various malformations within the syndrome and the need for the cooperation of several specialists in the diagnosis and treatment of children with the syndrome.

Inferior oblique muscle anteriorization in congenital superior oblique palsy.

BACKGROUND: Inferior oblique muscle overaction of variable amounts is usually present with congenital superior oblique palsy. Inferior oblique muscle anteriorization has been described as a suitable surgical procedure in this entity. The aim of this study was to investigate the effect of inferior oblique muscle anteriorization in patients with congenital superior oblique palsy on vertical, torsional and horizontal alignment. PATIENTS AND METHODS: The study was designed as an institutional retrospective cohort study. 45 patients with congenital superior oblique palsy (15 female, 30 male; mean age 36 years ± 19.2 SD, ranging from 6 to 75 years) underwent inferior oblique muscle anteriorization between 2000 and 2010. Preoperative amounts of vertical, torsional and horizontal deviation (using Harms tangent screen), measurements of Bielschowsky head tilt phenomenon as well as stereopsis (Lang test) were compared with findings three months and one year postoperatively. RESULTS: Preoperative vertical deviation in primary position measured 10.1° (mean; range 0-19). Three months postoperatively vertical deviation was significantly reduced (p<0.001) to 4° (mean; range 0-20). After one year vertical deviation measured 3.5° (mean; range 0-15). The values three months postoperatively did not significantly differ from those one year postoperatively (p=0.46). CONCLUSIONS: Inferior oblique muscle anteriorization leads to a significant and sustained improvement of ocular alignment in patients with congenital superior oblique palsy of various degrees of severity. Thus the procedure is recommendable as a first line treatment in this clinical situation.

MR imaging of congenital or developmental neuropathic strabismus: common and uncommon findings.

BACKGROUND AND PURPOSE: High-resolution MR imaging enables direct imaging of the ocular motor nerves. The aim of this study was to assess the various causes of congenital or developmental neuropathic strabismus by using high-resolution MR imaging. MATERIALS AND METHODS: High-resolution MR imaging was performed to evaluate the ocular motor nerves (CNIII, CNIV, CNVI) in 247 consecutive patients with suspected congenital or developmental neuropathic strabismus. These MR images, along with those obtained from conventional MR imaging of the brain and the orbit, were evaluated. RESULTS: MR imaging abnormalities were found in 112 patients: ocular motor nerve abnormalities in 98 patients (88%), orbital abnormalities in 9 patients (8%), and brain abnormalities in 5 patients (4%). Ocular motor nerve abnormalities were CNIV aplasia (63%), CNVI aplasia or hypoplasia (21%), CNIII aplasia or hypoplasia (3%), and combined CNIII aplasia and CNVI hypoplasia (1%). Orbital abnormalities were EOM hypoplasia (7%), EOM hypertrophy (1%), and fibrotic mass (1%). Brain abnormalities were periventricular leukomalacia (4%) and periventricular heterotopia (1%). CONCLUSIONS: Various MR imaging abnormalities were associated with congenital and developmental neuropathic strabismus. The most common abnormality was CNIV aplasia.

Primary nerve repair following resection of a neurenteric cyst of the oculomotor nerve.

Neurenteric cysts are rare congenital lesions of endodermal origin occurring in the spinal canal and infrequently in the posterior cranial fossa. The authors report the case of a 3-year-old child who presented with a recurrent third cranial nerve palsy. Magnetic resonance imaging showed a large cystic mass lesion in the ambient cistern on the right side, with compression of the anterolateral aspect of the brainstem. The patient underwent a craniotomy, complete excision, and a primary third cranial nerve repair. While there have been 3 reported cases of neurenteric cysts arising from the oculomotor nerve, this is the first documented case with a primary nerve repair.

Congenital absence of the superior oblique tendon in Noonan-neurofibromatosis syndrome.

A 5-year-old girl with Noonan-neurofibromatosis syndrome was diagnosed with bilateral superior oblique palsy. At surgery, the right superior oblique tendon was absent, and further exploration revealed abnormal tissue inserting into Tenon's capsule. Orbital imaging was not performed. Congenital absence of the superior oblique tendon was diagnosed. Although Noonan syndrome is known to have many ocular manifestations, absence of the superior oblique tendon has not been previously reported.

Evidence of an asymmetrical endophenotype in congenital fibrosis of extraocular muscles type 3 resulting from TUBB3 mutations.

PURPOSE: Orbital magnetic resonance imaging (MRI) was used to investigate the structural basis of motility abnormalities in congenital fibrosis of the extraocular muscles type 3 (CFEOM3), a disorder resulting from missense mutations in TUBB3, which encodes neuron-specific beta-tubulin isotype III. METHODS: Ophthalmic examinations in 13 volunteers from four CFEOM3 pedigrees and normal control subjects, were correlated with TUBB3 mutation and MRI findings that demonstrated extraocular muscle (EOM) size, location, contractility, and innervation. RESULTS: Volunteers included clinically affected and clinically unaffected carriers of R262C and D417N TUBB3 amino acid substitutions and one unaffected, mutation-negative family member. Subjects with CFEOM3 frequently had asymmetrical blepharoptosis, limited vertical duction, variable ophthalmoplegia, exotropia, and paradoxical abduction in infraduction. MRI demonstrated variable, asymmetrical levator palpebrae superioris and superior rectus EOM atrophy that correlated with blepharoptosis, deficient supraduction, and small orbital motor nerves. Additional EOMs exhibited variable hypoplasia that correlated with duction deficit, but the superior oblique muscle was spared. Ophthalmoplegia occurred only when the subarachnoid width of CN3 was <1.9 mm. A-pattern exotropia was frequent, correlating with apparent lateral rectus (LR) muscle misinnervation by CN3. Optic nerve (ON) cross sections were subnormal, but rectus pulley locations were normal. CONCLUSIONS: CFEOM3 caused by TUBB3 R262C and D417N amino acid substitutions features abnormalities of EOM innervation and function that correlate with subarachnoid CN3 hypoplasia, occasional abducens nerve hypoplasia, and subclinical ON hypoplasia that can resemble CFEOM1. Clinical and MRI findings in CFEOM3 are more variable than those in CFEOM1 and are often asymmetrical. Apparent LR innervation by the inferior rectus motor nerve is an overlapping feature of Duane retraction syndrome and CFEOM1. These findings suggest that CFEOM3 is an asymmetrical, variably penetrant, congenital cranial dysinnervation disorder leading to secondary EOM atrophy.

Marcus Gunn jaw winking with trigemino-oculomotor synkinesis of the inferior division of the oculomotor nerve.

Synkinetic aberrant innervation syndromes can involve abnormal movements of multiple extraocular and eyelid muscles. The authors describe a case of eyelid elevation associated with simultaneous adduction and depression of the eye upon chewing, sucking on a bottle, or wide opening of the mouth since birth. This represents a unique case of congenital Marcus Gunn jaw winking with trigemino-oculomotor synkinesis involving the inferior branch of the oculomotor nerve. The most likely explanation for these abnormal movements is prenatal aberrant innervation of eyelid and extraocular muscles.