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Clasp-knife Response
Clasp-knife response is a Golgi tendon reflex with a rapid decrease in resistance when attempting to flex a joint, usually during a neurological examination. It is one of the characteristic responses of an upper motor neuron lesion. It gets its name from the resemblance between the motion of the limb and the sudden closing of a claspknife after sufficient pressure is applied. Cause When a joint is passively flexed, the resisting force comes from the stretch reflex (or sometimes called tendon reflex) resulting from the extensor muscle being stretched. In upper motor neuron lesions, muscle tonus may increase and resistance of muscle to stretch increases. However, if sufficient force is applied, limb resistance suddenly decreases, presumably mediated by the Golgi tendon reflex (also call autogenic inhibition). Mechanism This reflex is observed in patients with upper motor neuron lesions. It was frequently attributed to the action of the golgi tendon organ, likely because of early ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golgi Tendon Reflex
The Golgi tendon reflex (also called inverse stretch reflex, autogenic inhibition, tendon reflex) is an inhibitory effect on the muscle resulting from the muscle tension stimulating Golgi tendon organs (GTO) of the muscle, and hence it is self-induced. The reflex arc is a negative feedback mechanism preventing too much tension on the muscle and tendon. When the tension is extreme, the inhibition can be so great it overcomes the excitatory effects on the muscle's alpha motoneurons causing the muscle to suddenly relax. This reflex is also called the inverse myotatic reflex, because it is the inverse of the stretch reflex. GTOs' inhibitory effects come from their reflex arcs: the Ib sensory fibers that are sent through the dorsal root into the spinal cord to synapse on Ib inhibitory interneurons that in turn terminate directly on the motor neurons that innervate the same muscle. The fibers also make direct excitatory synapses onto motoneurons that innervate the antagonist muscle. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurological Examination
A neurological examination is the assessment of sensory neuron and motor responses, especially reflexes, to determine whether the nervous system is impaired. This typically includes a physical examination and a review of the patient's medical history, but not deeper investigation such as neuroimaging. It can be used both as a screening tool and as an investigative tool, the former of which when examining the patient when there is no expected neurological deficit and the latter of which when examining a patient where you do expect to find abnormalities. If a problem is found either in an investigative or screening process, then further tests can be carried out to focus on a particular aspect of the nervous system (such as lumbar punctures and blood tests). In general, a neurological examination is focused on finding out whether there are lesions in the central and peripheral nervous systems or there is another diffuse process that is troubling the patient. Once the patient has be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Upper Motor Neuron Lesion
An upper motor neuron lesion (also known as pyramidal insufficiency) Is an injury or abnormality that occurs in the neural pathway above the anterior horn cell of the spinal cord or motor nuclei of the cranial nerves. Conversely, a lower motor neuron lesion affects nerve fibers traveling from the anterior horn of the spinal cord or the cranial motor nuclei to the relevant muscle(s). Upper motor neuron lesions occur in the brain or the spinal cord as the result of stroke, multiple sclerosis, traumatic brain injury, cerebral palsy, atypical parkinsonisms, multiple system atrophy, and amyotrophic lateral sclerosis. Symptoms Changes in muscle performance can be broadly described as the upper motor neuron syndrome. These changes vary depending on the site and the extent of the lesion, and may include: * Muscle weakness. known as 'pyramidal weakness' *Sloth sign. Decreased control of active movement, particularly slowness * Spasticity, a velocity-dependent change in muscle tone ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Claspknife
A pocketknife (also spelled as pocket knife) is a knife with one or more blades that fold into the handle. They are also known as jackknives, folding knives, EDC knife, or may be referred to as a penknife, though a penknife may also be a specific kind of pocketknife. A typical blade length is . Pocketknives are versatile tools, and may be used for anything from whittling and woodcarving, to butchering small game, gutting and filleting small fish, aiding in the preparation of tinder and kindling for fires, boring holes in soft material, to opening an envelope, cutting twine, slicing fruits and vegetables or as a means of self-defense. Pocketknives may also be used in conjunction with other tools and equipment for woodcraft and bushcraft. Specialised designs are also used for mushroom hunting and gardening. Pocketknives designed for gardening include pruning knives, which are folding knives with long curved blades used for pruning, trimming cuttings, taking buds and preparing m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stretch Reflex
The stretch reflex (myotatic reflex), or more accurately ''muscle stretch reflex'', is a muscle contraction in response to stretching a muscle. The function of the reflex is generally thought to be maintaining the muscle at a constant length but the response is often coordinated across multiple muscles and even joints. The older term ''deep tendon reflex'' is now criticized as misleading. Tendons have little to do with the response, and some muscles with stretch reflexes have no tendons. Rather, muscle spindles detect a stretch and convey the information to the central nervous system. As an example of a spinal reflex, it results in a fast response that involves an afferent signal into the spinal cord and an efferent signal out to the muscle. The stretch reflex can be a monosynaptic reflex which provides automatic regulation of skeletal muscle length, whereby the signal entering the spinal cord arises from a change in muscle length or velocity. It can also include a polysynaptic c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Muscle Tonus
In physiology, medicine, and anatomy, muscle tone (residual muscle tension or tonus) is the continuous and passive partial contraction of the muscles, or the muscle's resistance to passive stretch during resting state.O’Sullivan, S. B. (2007). Examination of motor function: Motor control and motor learning. In S. B. O’Sullivan, & T. J. Schmitz (Eds), Physical rehabilitation (5th ed.) (pp. 233-234). Philadelphia, Pennsylvania: F. A. Davis Company. It helps to maintain posture and declines during REM sleep. Muscle tone is regulated by the activity of the motor neurons and can be affected by various factors, including age, disease, and nerve damage. Purpose If a sudden pull or stretch occurs, the body responds by automatically increasing the muscle's tension, a reflex which helps guard against danger as well as helping maintain balance. Such near-continuous innervation can be thought of as a "default" or "steady state" condition for muscles. Both the extensor and flexor muscl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Golgi Tendon Organ
The Golgi tendon organ (GTO) (also called Golgi organ, tendon organ, neurotendinous organ or neurotendinous spindle) is a proprioceptor – a type of sensory receptor that senses changes in muscle tension. It lies at the interface between a muscle and its tendon known as the musculotendinous junction also known as the myotendinous junction. It provides the sensory component of the Golgi tendon reflex. The Golgi tendon organ is one of several eponymous terms named after the Italian physician Camillo Golgi. Structure The body of the Golgi tendon organ is made up of braided strands of collagen (intrafusal fasciculi) that are less compact than elsewhere in the tendon and are encapsulated. The capsule is connected in series (along a single path) with a group of muscle fibers () at one end, and merge into the tendon proper at the other. Each capsule is about long, has a diameter of about , and is perforated by one or more afferent type Ib sensory nerve fibers ( Aɑ fiber), whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypertonia
Hypertonia is a term sometimes used synonymously with ''spasticity'' and ''rigidity'' in the literature surrounding damage to the central nervous system, namely upper motor neuron lesions. Impaired ability of damaged motor neurons to regulate descending pathways gives rise to disordered spinal reflexes, increased excitability of muscle spindles, and decreased synaptic inhibition. These consequences result in abnormally increased muscle tone of symptomatic muscles. Some authors suggest that the current definition for spasticity, the velocity-dependent overactivity of the stretch reflex, is not sufficient as it fails to take into account patients exhibiting increased muscle tone in the absence of stretch reflex over-activity. They instead suggest that "reversible hypertonia" is more appropriate and represents a treatable condition that is responsive to various therapy modalities like drug or physical therapy. Presentation Symptoms associated with central nervous systems diso ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Somatic Motor System
Somatic may refer to: * Somatic (biology), referring to the cells of the body in contrast to the germ line cells ** Somatic cell, a non-gametic cell in a multicellular organism * Somatic nervous system, the portion of the vertebrate nervous system which regulates voluntary movements of the body * Somatics, a group of alternative medicine approaches, experiential movement disciplines, and dance techniques * Somatic theory, a model of human social behavior Related concepts * Somatic marker hypothesis, an explanation of how emotions affect decision-making * Somatic symptom disorder, aka somatoform disorder, characterized by medically unexplained physical symptoms, and considered to be a mental health issue * Somatotype, the now-discredited idea associating body types with human temperament types * Psychosomatic medicine, an interdisciplinary medical field exploring the relationships among social, psychological, and behavioral factors on bodily processes and quality of life in h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurophysiology
Neurophysiology is a branch of physiology and neuroscience concerned with the functions of the nervous system and their mechanisms. The term ''neurophysiology'' originates from the Greek word ''νεῦρον'' ("nerve") and ''physiology'' (which is, in turn, derived from the Greek ''φύσις'', meaning "nature", and ''-λογία'', meaning "knowledge"). Neurophysiology has applications in the prevention, diagnosis, and treatment of many neurological and psychiatric diseases. Neurophysiological techniques are also used by clinical neurophysiologists to diagnose and monitor patients with neurological diseases. The field involves all levels of nervous system function, from molecules and cells to systems and whole organisms. Areas of study include: * The electrochemical properties of neurons * Function and regulation of proteins in neurons and glia * Metabolic reactions relevant to neural function * Cell signalling in the nervous system * Neurotransmission and synaptic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
