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The Spinal Cord and the Spinal Canal
Published in Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand, Pediatric Regional Anesthesia, 2019
Bernard J. Dalens, Jean-Pierre Monnet, Yves Harmand
The neurons of the ventral horns are voluminous and poorly limited anteriorly. They include numerous neurons organized into cell groups, usually referred to as nuclei or cell columns. These columns are usually divided into three main groups, medial, central and lateral. All of these exhibit further division at various levels of the cord. The most important nuclei are shown in Figure 1.19. They are formed by large multipolar cells named on the basis of their location. They contribute axons to the respective ventral root and supply the voluntary muscles. Before emerging from the spinal canal, some fibers give rise to collaterals which reenter the gray matter.
The nervous system
Published in Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella, Essentials of Human Physiology and Pathophysiology for Pharmacy and Allied Health, 2019
Laurie K. McCorry, Martin M. Zdanowicz, Cynthia Y. Gonnella
The dorsal root contains afferent, or sensory, neurons. Impulses in these neurons travel from peripheral tissues toward the spinal cord. The dorsal root joins the spinal cord laterally, toward the posterior surface of the cord (Figure 13.5). The ventral root contains efferent, or motor, neurons. Impulses in these neurons travel away from the spinal cord toward the peripheral tissues. The ventral root exits the spinal cord laterally, toward the anterior surface of the cord.
Nerve
Published in Manoj Ramachandran, Tom Nunn, Basic Orthopaedic Sciences, 2018
Mike Fox, Caroline Hing, Sam Heaton, Rolfe Birch
The spinal nerves divide close to the spinal cord, forming a sensory dorsal root and a motor ventral root. The cell body of the sensory nerve is situated in the dorsal root ganglion. The motor nerve’s cell body is situated in the spinal cord (Figure 11.4).
Temperature sensitivity in multiple sclerosis: An overview of its impact on sensory and cognitive symptoms
Published in Temperature, 2018
Aikaterini Christogianni, Richard Bibb, Scott L Davis, Ollie Jay, Michael Barnett, Nikos Evangelou, Davide Filingeri
The effects of increases in core temperature on conduction block have been investigated in demyelinated nerve fibres using animal models [57]. For example, Rasminsky (1973) [100] investigated the activities between internodes in a demyelinated rat ventral root nerve fibre which would fire slower action potentials across the axon in comparison to a myelinated nerve fibre. Conduction within the demyelinated nerve fibre was blocked when fibre temperature was raised to and beyond 36.5°C. On the contrary conduction was (partially) re-established when fibre’s temperature was lowered below 36.5°C. In highlighting conduction slowing in demyelinated fibres exposed to increased temperatures, this study provided insights on the potential roots of the role of changes in core temperature in the symptoms worsening observed in MS patients experiencing heat sensitivity.
Neurological complications of Zika virus infection
Published in Expert Review of Anti-infective Therapy, 2018
Arthrogriposis and other osteoarticular malformations have been seen in severe cases and were associated with poor intrauterine movement and thinning of spinal cord. A neurogenic origin with secondary involvement or motor neurons has been proposed. Arthrogriposis can happen following degeneration of long descending tracts and motor neurons of corticospinal tract in spinal cord and brainstem, causing decreased fetal movements and even akinesia, and fixed postures and deformities [38,39]. Thinning of spinal cord and reduced ventral roots has been seen on spine MRI in CZS patients having arthrogryposis [40]. Other orthopedic abnormalities include hip dislocation, clubfoot, camptodactyly, and contractures with flexed wrist and fingers [41].
Disruption of the network between Onuf’s nucleus and myenteric ganglia, and developing Hirschsprung-like disease following spinal subarachnoid haemorrhage: an experimental study
Published in International Journal of Neuroscience, 2019
Ozgur Caglar, Binali Firinci, Mehmet Dumlu Aydin, Erdem Karadeniz, Ali Ahiskalioglu, Sare Altas Sipal, Murat Yigiter, Ahmet Bedii Salman
According to the classic understanding of the autonomic innervation of human in the lower abdomen, parasympathetic ganglion cells are located near the pelvic viscera and in the pelvic plexus, whereas sympathetic ganglion cells exist along the lumbar and sacralsympathetic trunks [11]. Affection of these nerves lead to sexual and sphincter dysfunction in human [11]. This dysfunction seems to be dependent to damage to the hypogastric nervous plexus. The superior and inferior hypogastric plexuses receive input from sympathetic preganglionic fibres whose cell bodies reside in the intermediolateral cell columns of the lower spinal cord. Same mechanism may be responsible in Hirschprung Disease. The superior and inferior hypogastric plexuses receive input from sympathetic preganglionic fibres whose cell bodies reside in the intermediolateral cell columns of the lower spinal cord [12] or the sacral spinal cord. This cell group was first described in 1899 by Onufrowicz and became as known as Onuf's nucleus. These efferent, preganglionic fibres first leave the spinal cord via the ventral roots of spinal nerves and exit the spinal nerves via the white rami communicantes into the lumbosacral sympathetic chain [12]. Onuf’s nucleus is localized mainly in S3–4 segments. It is composed of organized medium-sized neurons and located in the ventrolateral aspect of the ventral horn of the first sacral segment. Onuf’s nucleus has different cortical afferent connections with contralateral corticospinal tract fibres [13] and contains motorneurons that innervate the pelvic floor muscles, including the external urethral and anal sphincters, and manage micturition, vomiting, defecation, and parturition reflexes [14].