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Brain regions, lesions, and stroke syndromes
Published in Christos Tziotzios, Jesse Dawson, Matthew Walters, Kennedy R Lees, Stroke in Practice, 2017
Christos Tziotzios, Jesse Dawson, Matthew Walters, Kennedy R Lees
The midline basilar artery runs up in front of the pons to give off the small pontine branches, which supply, as their name betrays, the pons. The anterior inferior cerebellar artery and the labyrinthine artery are also branches of the basilar artery and supply anterior and inferior cerebellum and inner ear, respectively. The basilar artery ascends up and ends at the upper end of the pons by dividing into the superior cerebellar branches just before giving rise to the posterior cerebral arteries. The former supplies the remaining superior part of the cerebellum, as well as the mesencephalon and upper pons. The posterior cerebral artery supplies the visual cortex of the occipital lobe (but the macula can be MCA-supplied). The inferomedial portion of the temporal lobe, posterior and inferior parts of parietal, and the lateral thalamus (via the thalamogeniculate branch) are also supplied by the PCA. It should be noted that the posterior cerebral artery may receive some of its blood from the internal carotid and not the basilar, the basilar artery being a later embryological development. A number of perforating arteries arising from the posterior cerebral or the posterior communicating arteries (see below) supply the anterior part of the midbrain and aspects of subthalamus and hypothalamus. In summary, the posterior cerebral arteries are crucial to the occipital lobes, midbrain, thalamus, and parts of the temporal and parietal lobes.
Perivascular Innervation In Special Sensory Organs With Particular Reference To The Presence of Neuropeptides
Published in Geoffrey Burnstock, Susan G. Griffith, Nonadrenergic Innervation of Blood Vessels, 2019
Rolf Uddman, Rolf Håkanson, Frank Sundler
The inner ear receives its main blood supply from the labyrinthine artery, a branch of the basilar artery. When entering the internal auditory meatus, the labyrinthine artery gives off branches to the vestibular organ and continues as the cochlear artery. It enters the modiolus together with the cochlear nerve and runs spirally through the modiolus, giving rise to the spiral modiolar arteries which ramify into small arterioles and capillaries supplying the organ of Corti, the spiral ligament, and the stria vascularis. The venous drainage has an analogous distribution. A schematic outline of the blood supply to the inner ear is given in Figure 1. Early histochemical studies have revealed a rich supply of adrenergic nerve fibers around the labyrinthine, cochlear, and vestibular arteries.1,2 The adrenergic perivascular network gradually disappears as the vessels are followed in peripheral direction (Figure 2a). The vessels of the spiral ligament and the stria vascularis do not seem to contain adrenergic fibers.1 The innervation of the blood vessels in the vestibular organ is less well studied. Terayama et al.3 found that the major blood vessels to the vestibular apparatus contained a network of adrenergic nerve fibers that disappeared gradually when the vessels were followed in a peripheral direction. Extirpation of the cervical sympathetic ganglia eliminated the perivascular adrenergic nerve fibers in the inner ear.3,4 The effect of sympathetic stimulation on the blood flow to the inner ear has been assessed by the use of several different techniques giving partly conflicting results. On the whole, sympathetic stimulation seems to give a moderate reduction in cochlear blood flow.5,6
The Facial Nerve and its Non-Neoplastic Disorders
Published in John C Watkinson, Raymond W Clarke, Christopher P Aldren, Doris-Eva Bamiou, Raymond W Clarke, Richard M Irving, Haytham Kubba, Shakeel R Saeed, Paediatrics, The Ear, Skull Base, 2018
Christopher Skilbeck, Susan Standring, Michael Gleeson
The arterial supply of the segments of the facial nerve is derived from branches of the vertebrobasilar and ECA systems (Figure 112.6).61,62 The labyrinthine artery (internal auditory artery) supplies the cisternal, meatal and labyrinthine segments. It usually arises directly from the AICA as it loops between the cisternal segments of the motor root of the facial nerve, the nervus intermedius and the vestibulocochlear nerves, projecting towards and often into the IAM, but it may arise from the basilar, vertebral or superior cerebellar arteries.63 The greater petrosal nerve is supplied by the petrosal branch of the middle meningeal artery which usually passes through the bone enclosing the geniculate ganglion and tympanic segment of the nerve, less commonly it passes through the hiatus of the greater petrosal nerve: the vessel and nerve are at risk during procedures where the dura is elevated from the floor of the MCF.64 The tympanic and mastoid segments are supplied by the facial arch, an anastomotic network formed by the superficial petrosal branch of the middle meningeal artery and the stylomastoid branch of either the occipital or posterior auricular arteries, which enters the facial canal via the stylomastoid foramen. The lowest branch from the stylomastoid artery to the facial nerve is given off at the level of the origin of the chorda tympani: collaterals of the stylomastoid artery supply the chorda tympani. Branches from the facial arch anastomose with vessels supplying the bone marrow of the facial canal and with anterior and superior tympanic branches of the maxillary artery, the posterior tympanic branch of the posterior auricular artery, and the inferior tympanic branch of the ascending pharyngeal artery.65 The posterior auricular and occipital arteries and their branches, including the stylomastoid artery, supply the facial nerve from the stylomastoid foramen to the parotid gland. The temporofacial and cervicofacial branches that exit the parotid gland are supplied by collaterals of the superficial temporal, transverse facial, facial and maxillary arteries.
The applications of targeted delivery for gene therapies in hearing loss
Published in Journal of Drug Targeting, 2023
Melissa Jones, Bozica Kovacevic, Corina Mihaela Ionescu, Susbin Raj Wagle, Christina Quintas, Elaine Y. M. Wong, Momir Mikov, Armin Mooranian, Hani Al-Salami
Effective drug delivery to the inner ear is a complex undertaking. Barriers to such include physical obstructions due to the intricate structure of the ear and access to the round window membrane for delivery. In addition, the difficult anatomical challenges, including the blood-inner ear barrier and a limited labyrinthine artery supply must be accounted for [56,57]. Further obstacles come in the manner of passing through the round window membrane, with permeability greatly impacted by a range of factors. Post-permeation, challenges are also encountered in terms of the diffusion, distribution, and rate of clearance [57]. In addition, non-specific delivery is a major hurdle, with the potential for off-target effects [6]. The use of nanotechnology may assist in overcoming many of the obstacles encountered, whilst providing a non-invasive system which also is biocompatible and offers a sustained delivery system, with the potential to be further optimised for use in targeted delivery, as will be discussed throughout this review.
The Pathogenesis of secondary forms of Autoimmune Inner Ear Disease (AIED): advancing beyond the audiogram data
Published in Expert Review of Clinical Immunology, 2021
Virginia Corazzi, Stavros Hatzopoulos, Chiara Bianchini, Magdalena B Skarżyńska, Stefano Pelucchi, Piotr Henryk Skarżyński, Andrea Ciorba
The immune-complex deposition in the labyrinthine artery is reported to cause vasculitis, reducing the vessel caliber, and consequently decreasing the blood supply to the inner ear [59]. The subsequent cochlear micro-infarctions lead to hair cells and spiral ganglions damage, with SNHL onset [59]. Auto-antibody production has been considered playing an important role in the pathogenesis of SNHL in systemic rheumatoid disease, due to a direct cytotoxic damage, and to immune-complex formation and immune-complex-related inflammation [22]. Human antibodies and T-cells specific for cochlin, a protein predominantly expressed in the inner ear with an important role in maintaining the vestibule homeostasis, have been observed in patients with idiopathic SNHL [60]; this immune response to cochlin has been addressed as a possible pathogenetic theory in autoimmune hearing loss, suggesting a strong relation between cochlin and AIED [22]. Nonetheless, Tsirves et al. [22] on a total of 133 patients with systemic rheumatic disease, did not find any statistically significant correlation between hearing loss and anti-cochlin IgG antibodies.
Inner Ear Complications in Children and Adolescents with Sickle Cell Disease
Published in Hemoglobin, 2020
Azza A.G. Tantawy, Safaa W. Ibrahim, Togan T. Abdel-Aziz, Amr N. Rabie, Sara M. Makkeyah, Iman A. Ragab
The membranous labyrinth is supplied by the labyrinthine artery that either arises from the anterior inferior cerebellar artery or as a direct branch of the BA. Whether the flow velocity could be predictive of labyrinthine pathology remains to be answered; vaso-occlusion in patients with sickle cell disease can occur within any organ and the labyrinthine artery has a higher chance of vaso-occlusion due to its small caliber. It is of interest that two out the five patients with abnormal MRI findings had past history of frequent dactylitis in early life. Those two patients also had silent MRI ischemic foci, however, none of them had SNHL. A significant relationship between hearing loss and dactylitis in early childhood was previously reported by other investigators [7], however, they did not investigate the inner ear MRI findings in their study cohort.