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Cranial nerves
Published in Ibrahim Natalwala, Ammar Natalwala, E Glucksman, MCQs in Neurology and Neurosurgery for Medical Students, 2022
Ibrahim Natalwala, Ammar Natalwala, E Glucksman
Regarding clinical abnormalities of the pupils, which of the following are true and which are false? Horner’s syndrome is caused by a lesion to the parasympathetic pathway and causes a unilateral constricted pupil with associated ptosis.In a relative afferent pupillary defect (RAPD), the consensual light reflex is weaker than the direct light reflex.Argyll Robertson pupils are small, accommodate to near objects but are unreactive to light.Denervation of the ciliary ganglion can lead to a dilated pupil that reacts slowly to bright light.The Edinger-Westphal nucleus responsible for pupillary constriction is located in the midbrain at the level of the superior cerebellar peduncle.
Head and Neck
Published in Bobby Krishnachetty, Abdul Syed, Harriet Scott, Applied Anatomy for the FRCA, 2020
Bobby Krishnachetty, Abdul Syed, Harriet Scott
Autonomic Sympathetic – pupillary dilatation By long and short ciliary nerves via superior cervical ganglionParasympathetic – pupillary constriction By short postganglionic ciliary nerve via ciliary ganglionPreganglionic supply via CN III
Argyll Robertson Pupils (Ar Pupils)
Published in K. Gupta, P. Carmichael, A. Zumla, 100 Short Cases for the MRCP, 2020
K. Gupta, P. Carmichael, A. Zumla
Although in your practice of clinical medicine you may have seen only a few patients with AR pupils, it is not uncommon to see such patients as short cases in the MRCP examination. The exact site of lesion in these patients is not known but it is thought to be the ciliary ganglion. The four important characteristics of AR pupils are: Bilateral, small, irregular and unequal pupils.There may be associated atrophy and depigmentation of the iris.Pupils fail to react to light but accommodation reflex is retained.Pupils fail to dilate properly in response to mydriatic drugs. The above four features are almost diagnostic of neurosyphilis although many of the features may occur in diabetes mellitus, orbital injury, hereditary neuropathies and in sarcoidosis.
Factors affecting the prevalence, severity, and characteristics of ocular surface pain
Published in Expert Review of Ophthalmology, 2023
Victor Sanchez, Noah K Cohen, Elizabeth R Felix, Anat Galor
The high density of nerve fibers in the cornea may contribute to the frequency of ocular surface pain in the general population. In fact, the corneal surface is among the most densely innervated regions within the human body [27]. Most of these are sensory fibers [28], which travel from the ophthalmic branch (V1) of the trigeminal nerve, through the nasociliary branch and into the ciliary ganglion. The ciliary ganglion gives rise to ciliary nerves which circumferentially innervate the cornea and surrounding anterior bulbar conjunctiva [29]. Estimates in animals suggest that between 50 and 450 trigeminal ganglion neurons supply the cornea, accounting for 2% of all trigeminal ganglion neurons [29–32]. The majority of sensory fibers innervating the cornea are polymodal nociceptors, which are activated over a wide range of stimulus intensities including noxious mechanical energy, heat, chemical irritants, as well as endogenous chemical mediators released by damaged corneal tissues [33–35]. Mechanistically, reduced tear secretion, rapid tear evaporation, or abnormal tear composition can lead to epithelial cell damage and production of inflammatory mediators that activate polymodal neurons, generating ocular surface pain [36,37].
Diagnosis and Management of Post Traumatic Recurrent Unilateral Accommodative Spasm—A Case Report
Published in Journal of Binocular Vision and Ocular Motility, 2022
Praveen Kumar P, Amit Bhowmick, Neha Mahabale, Jameel Rizwana Hussaindeen, Dhanashree Ratra
This case report illustrates the presence of unilateral accommodative spasm, a rare clinical entity, and to the best of our knowledge, there are very few reports that have documented the same.7–12 All these cases of unilateral accommodative spasm were documented to have moderate to severe visual impairment, while our patient had mild visual impairment. The computational eye model to understand the impact of blunt injury demonstrated that the stress on the zonules could cause deformation of the lens.13 Ciliary muscle spasm, when circumference of zonules gets affected, presents with temporary incline toward myopic error.14 It is also reported that the trauma can damage the ciliary ganglion, leading to increased parasympathetic activity.8 In our case, the trivial injury on the left side followed by the traumatic events could have potentially resulted in a shock, leading to unilateral spasm of accommodation. The patient also reported increased stress levels at workplace due to the nature of the armed professions itself. A report by Tokiwa et al. also documented psychogenic etiology to be one of the causes for unilateral accommodative spasm.6 The manifestation of spasm was reported in the unaffected eye when the affected eye was occluded.11 In our report, to understand the manifestation in the unaffected eye, we had examined all the accommodation parameters when the affected eye was occluded.
Transient anisocoria after a traumatic cervical spinal cord injury: A case report
Published in The Journal of Spinal Cord Medicine, 2020
Paul Overdorf, Gary J. Farkas, Natasha Romanoski
The sympathetic innervation to the eye is from the superior cervical ganglion (Fig. 1). The superior cervical ganglion lies anterior to the transverse processes of the second and third cervical vertebra. Anterior to the ganglion lies the carotid sheath with the internal carotid artery, internal jugular vein, and vagus nerve, while the longus capitis muscle is found posterior to the ganglion. Postganglionic sympathetic fibers from the superior cervical ganglion are distributed onto the internal carotid artery and help to form the internal carotid nerve plexus, which ascends on the internal carotid artery into the carotid canal to enter the cranial cavity (Fig. 1).11 Once in the cranial cavity, postganglionic fibers from the internal carotid nerve plexus travel on the nasociliary nerve of the ophthalmic division of the trigeminal nerve, while other fibers continue from the internal carotid nerve plexus as the sympathetic root of the ciliary ganglion.12 The sympathetic root of the ciliary ganglion traverses the ciliary ganglion without synapsing (Fig. 1). These nerves then travel on the short ciliary nerves of the ciliary ganglion to the eye where they innervate the dilator pupillae muscle. Some of these postganglionic sympathetic fibers also travel on the long ciliary nerve, a nerve branch of the nasociliary nerve, to reach the eye (Fig. 1). Sympathetic activation of the dilator pupillae muscle dilates the pupil.11,12