| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 3,913,304,543 visitors served. |
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
Paralysis |
Also found in: Dictionary/thesaurus, Medical, Legal, Wikipedia | 0.01 sec. |
|
|
paralysis or palsy (pôl`zē), complete loss or impairment of the ability to use voluntary muscles, usually as the result of a disorder of the nervous system. The nervous tissue that is injured may be in the brain, the spinal cord, or in the muscles themselves. Accordingly there may be general paralysis, involvement of only one side (hemiplegia), paralysis on both sides at one level (paraplegia paraplegia , paralysis of the lower part of the body, commonly affecting both legs and often internal organs below the waist. When both legs and arms are affected, the condition is called quadriplegia.
..... Click the link for more information. or quadriplegia), or localized paralysis in a small group of nerves or muscles. The cause of paralysis may be any injury that tears or compresses the nerves; it may be hemorrhage, tumor, infection, or substances toxic to nerve tissue. One of the most frequent causes of paralysis is stroke stroke, destruction of brain tissue as a result of intracerebral hemorrhage or infarction caused by thrombosis (clotting) or embolus (obstruction in a blood vessel caused by clotted blood or other foreign matter circulating in the bloodstream); formerly called paralysisor palsyLoss or impairment of voluntary use of one or more muscles. It may be flaccid (with loss of muscle tone) or spastic (stiff). Hemiplegia (one-sided paralysis) is usually caused by stroke or brain tumour on the opposite side. Diplegia (two-sided paralysis, as in cerebral palsy) results from generalized brain disease. Spinal-cord damage (from bone or joint disease, fracture, or tumour affecting the vertebrae; inflammatory and degenerative diseases; or pernicious anemia) paralyzes the body at and below the level of the damage (paraplegia if the legs and lower body only; quadriplegia if arms and legs). Poliomyelitis and polyneuritis (neuritis of multiple nerves) result in paralysis with muscle wasting. Bell palsy (a type of neuritis) paralyzes the muscles of one side of the face. Muscular dystrophy causes paralysis by attacking muscle. Metabolic causes include myasthenia gravis. Paralysis may also have psychiatric causes (see hysteria). paralysis Pathol a. impairment or loss of voluntary muscle function or of sensation (sensory paralysis) in a part or area of the body, usually caused by a lesion or disorder of the muscles or the nerves supplying them b. a disease characterized by such impairment or loss; palsy paralysis [pə′ral·ə·səs] (medicine) Complete or partial loss of motor or sensory function. Paralysis absence of voluntary movement that is due to destruction or impairment of the motor centers of the spinal cord or brain or of tracts of the central or peripheral nervous system. A distinction is made between paralysis and paresis, the latter being a condition in which motor functions are weakened but present. Both conditions may be caused by disturbances of the blood circulation, inflammation, traumata, or tumors of the nervous system. An unusual kind of paralysis occurs in hysteria. Paralyses must be distinguished from motor disorders associated with inflammation of muscles and lesions of bones and joints, which restrict the range of movement mechanically. Paralysis may affect one muscle, one extremity (monoplegia), the arm and leg on one side (hemiplegia), both arms or both legs (paraplegia), or other combinations of muscles. Peripheral paralysis is a flaccid paralysis that involves the motor cells of the spinal cord and its anterior roots, peripheral nerves, plexuses, or nuclei of the cranial nerves. Central paralysis is a spastic paralysis that involves the brain’s central motor neurons or their outgrowths in the spinal cord. Peripheral paralysis is characterized by the complete absence of movement, decrease in muscle tone, loss of reflexes, and muscular atrophy. Sensory disorders occur when a peripheral nerve or plexus containing both motor and sensory fibers is affected. Central paralysis is characterized not by the complete loss of motor functions but by their dissociation—the loss of some functions and intensification of others. While voluntary movement is absent, muscle tone and tendon and periosteal reflexes increase and pathological Babinski’s, Rossolimo’s, and other reflexes appear. Associated movements (synkinesis) are observed. These are involuntary movements that occur in paralyzed extremities during voluntary movements of healthy extremities. Sensory disturbances are also observed. Extrapyrimidal paralysis arises when the subcortical structures of the brain are affected. Associated, reflex, and voluntary movements are absent (akinesia). Muscle tone is plastic, and the extremity can move only passively. Electromyography and other special methods of examination are important for differential diagnosis. The prognosis and treatment are determined by the disease that caused the paralysis. Among the special methods used to restore the functions of the extremity are massage and remedial gymnastics. REFERENCESKrol’, M. B., and E. A. Fedorova. Osnovnye nevropatologicheskie sindromy. Moscow, 1966.Kukuev, L. A. Struktura dvigatel’nogo analizatora. Leningrad, 1968. V. B. GEL’FAND Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content. |
|
| Encyclopedia |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup |
|---|