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Spinal CordAnatomical and Physiological Features
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
The three main ascending spinal tracts are (i) dorsal column medial lemniscus pathway, (ii) spinothalamic tract and (iii) spinocerebellar tract. The dorsal column medial lemniscus conveys information for the perception of pressure, vibration and texture via Aα/β fibres to facilitate discriminative touch. The spinothalamic tract conveys pain and temperature modalities via Aδ/C fibres. Proprioception is conveyed via Aα fibres which terminate at the cerebellum by the spinocerebellar tract. Details of the course of the ascending tracts are described in Chapter 8.
The nervous system
Published in Peter Kopelman, Dame Jane Dacre, Handbook of Clinical Skills, 2019
Peter Kopelman, Dame Jane Dacre
At the level of the medulla, the spinothalamic fibres touch and pass laterally, while the posterior columns enter the medial lemniscus. A lesion at the level of the medulla (or above) will involve all sensory fibres from the opposite half of the body. Higher in the brainstem, the two sensory pathways are joined by the second- order sensory fibres from cranial nerve nuclei (Fig. 6.3). The fibres of the medial lemniscus and spinothalamic tract synapse in the thalamus. The fibres finally ascend through the internal capsule to the cerebral cortex.
Non-Synonyms (Similar-Sounding)
Published in Terence R. Anthoney, Neuroanatomy and the Neurologic Exam, 2017
Medial lemniscus* (B&K, p. 275): An ascending brainstem tract, associated functionally with touch sensation mediated by spinal nerves (i.e., exclusive of the pre-auricular head). When used without modifiers, terms such as “lemniscal fibers” or“lemniscal pathway” usually refer to structures associated with the medial lemniscus.
Bilateral Tapia’s syndrome secondary to cervical spine injury: a case report and literature review
Published in British Journal of Neurosurgery, 2023
Alexandros G. Brotis, Jiannis Hajiioannou, Christos Tzerefos, Christos Korais, Efthymios Dardiotis, Kostas N. Fountas, Kostantinos Paterakis
Any lesion at their common pathway may manifest as a TS, particularly in the medulla (central TS) and between the oropharynx, upper cervical spine, styloid process, and lower mandible (peripheral TS). The initial description by A. G. Tapia at the beginning of the 19th century included right side paralysis of the larynx and the tongue and total contralateral hemiplegia in a bullfighter with “coryza” who was struck by a bull on the lateral side of his neck.1 The above-mentioned clinical constellation is compatible with a centrally located lesion at the tegmentum of the brainstem, particularly due to the presence of contralateral hemiplegia. However, our patient presented no symptoms and signs from the pyramidal tract, medial lemniscus, and the parasympathetic system. Consequently, he suffered from the peripheral variant of the TS.
The effect of propofol-based anesthesia versus low dose propofol with less than half MAC sevoflurane on intraoperative trans-cranial motor evoked potential during spine surgeries: Ratios rather than values
Published in Egyptian Journal of Anaesthesia, 2022
Samir A. Elkafrawy, Eman S. Zayed, Khaled A Mostafa, Islam M. Kandeel, Ahmed A. Mohammed, Mohammed M. Hassan
Previously, Stagnara’s wake-up test was widely used to monitor intraoperative iatrogenic spinal injuries, which involved waking the patient during surgery to ask him/her to move the suspected limb. In fact, this test was not appropriate to many patients either due to personal variations (cognitive), anesthetic environment (depth of anesthesia needed to accommodate surgery) or the long time elapsed from the injury that made ultimate correction unachievable. [2] Choosing the appropriate modality to monitor a specific surgery is challenging; SSEP, monitoring the dorsal column-medial lemniscus pathway may not detect anterior cord injuries which is the main nightmare during surgeries. On the other hand, MEP is monitoring the corticospinal pathway (which is not covered by SSEP). Hence, MEP monitoring was introduced as a faster (but not continuous) intraoperative monitoring modality with a great success rate, especially Transcranial approach (TcMEP), which was introduced by Merton and Morton in 1980. [3]
Proceedings of the 42nd Annual and First Virtual Upper Midwest Neuro-Ophthalmology Group Meeting, 24 July 2020
Published in Neuro-Ophthalmology, 2020
Salma Yassine, Francisco R. Sanchez Moreno, John J. Chen, Collin McClelland
Andre Aung, MD, Henry Ford Hospital, presented a 48-year-old female who was admitted to the hospital for pancreatitis and recurrent nausea/vomiting with gradual blurring of vision in both eyes for 1 week. Examination showed horizontal gaze-evoked nystagmus, partial horizontal gaze palsy, and symmetric segmental temporal disc oedema involving the papillomacular bundle of both eyes. MRI brain disclosed a thin T2-hyperintensity in the medial lemniscus. Vitamin levels disclosed decreased B1, B6, and folate levels. Based on her MRI findings and vitamin testing, she was diagnosed with Wernicke’s encephalopathy. The patient was started on intravenous thiamine and transitioned to indefinite oral thiamine with improvement in vision. This case highlights that thiamine deficiency can present with an optic neuropathy and associated optic disc oedema in addition to more typical presenting features of nystagmus and ophthalmoplegia.