Related Experiment Video
Updated: Jul 7, 2026
08:04
Identification and Classification of Position-specific GABAA Receptor Subunit Missense Variants for Their Role In Hippocampal Pyramidal Neurons
Published on: June 6, 2025
The Lhermitte phenomenon: variant forms and their significance.
1Neurosciences Department, Monash Medical Centre, 246 Clayton Road, Clayton, Victoria 3168, Australia. peter.kempster@southernhealth.org.au
Summary
Lhermitte phenomenon, a tingling sensation with neck movement, signals spinal cord issues. Variants like delayed or reverse Lhermitte phenomenon indicate specific spinal cord pathologies such as demyelination or compression.
Area of Science:
- Neurology
- Neuroscience
- Spinal Cord Medicine
Background:
- Lhermitte phenomenon is a neurological sign associated with spinal cord conditions.
- Understanding its variants is crucial for accurate diagnosis and treatment.
- Cervical spinal cord pathology is a common cause of typical Lhermitte phenomenon.
Observation:
- Typical Lhermitte phenomenon involves tingling sensations moving down the limbs or trunk upon neck flexion.
- Delayed Lhermitte phenomenon can occur after cervical trauma.
- Reverse Lhermitte phenomenon, induced by neck extension, often suggests extrinsic cervical spinal cord compression.
Findings:
- The inverse Lhermitte phenomenon, characterized by upward paresthesia with neck flexion, is a rare variant.
- This inverse form can be indicative of myelopathy resulting from nitrous oxide inhalation.
Implications:
- Recognizing Lhermitte phenomenon variants aids in differentiating between intrinsic and extrinsic spinal cord pathologies.
- Early identification of specific causes, like nitrous oxide exposure, is vital for timely intervention.
- Further research into the underlying mechanisms of Lhermitte phenomenon variants can improve diagnostic accuracy.
Related Concept Videos
01:27Indeterminate Forms and L’Hôpital’s Rule
Indeterminate forms occur when evaluating limits leads to expressions that cannot be directly interpreted, such as zero divided by zero or infinity divided by infinity. These results do not describe the true behavior of a function near a given point and instead signal that additional analysis is required. L’Hôpital’s Rule provides a reliable method for resolving such ambiguities by replacing the original functions with their derivatives.Core Idea of L’Hôpital’s RuleL’Hôpital’s Rule applies when...
01:22Generalized Hooke's Law
The generalized Hooke's Law is a broadened version of Hooke's Law, which extends to all types of stress and in every direction. Consider an isotropic material shaped into a cube subjected to multiaxial loading. In this scenario, normal stresses are exerted along the three coordinate axes. As a result of these stresses, the cubic shape deforms into a rectangular parallelepiped. Despite this deformation, the new shape maintains equal sides, and there is a normal strain in the direction of the...
01:29Tetanus
Tetanus is a life-threatening neurological disorder characterized by persistent muscle contractions and spastic paralysis. It is caused by Clostridium tetani, a motile, Gram-positive, rod-shaped, obligate anaerobe. These bacteria produce terminal endospores, giving them a distinctive “lollipop” or “tennis-racket” appearance. They thrive in anaerobic environments, such as those found in deep puncture wounds.Once introduced into the body, the spores germinate into vegetative cells. These cells...
01:12Alterations in Muscle Tone ll
Alterations in muscle tone are common manifestations of neurological disorders and reflect dysfunction within different nervous system regions. Spasticity, paratonia, and dystonia represent distinct forms of hypertonia, each with unique mechanisms, clinical features, and diagnostic importance.CharacteristicsSpasticity happens from upper motor neuron lesions and is characterized by velocity-dependent resistance to passive movement. Clinical features include:Exaggerated deep tendon reflexesClonus...
01:20Torsion in Vector Calculus
A toy train ascending a winding track that curves and tilts offers an intuitive view of torsion, a key geometric concept in the study of space curves. While curvature measures how sharply a path bends, torsion captures how the path twists out of the plane of bending. This twisting behavior is crucial in understanding three-dimensional motion and is precisely described using the Frenet–Serret framework.At each point along a space curve, the Frenet–Serret frame consists of three orthogonal unit...
01:15Lenz's Law
The direction in which the induced emf drives the current around a wire loop can be found through the negative sign. However, it is usually easier to determine this direction with Lenz's law, named in honor of its discoverer, Heinrich Lenz (1804–1865). Lenz's law states that the direction of the induced emf drives the current around a wire loop always to oppose the change in magnetic flux that causes the emf.
If a bar magnet is moved toward a coil such that the magnetic flux through the coil...
If a bar magnet is moved toward a coil such that the magnetic flux through the coil...