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INVOLUNTARY MOVEMENTS
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F.Rostami
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Involuntarymusclecontractions
Shivering Tremor Tics Tetany Myoclonus Seizures(Con vulsions) Opisthotonos
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This is a continuous, repetitive twitching (uncontrolled motions)of skeletal muscles,
which is usually visible and palpable The muscle units involved may be small and cause only local skin movement
tremor is described as fasciculations The muscle units may be extensive movement much coarser and sufficient to
move the extremities, eyes or parts of the trunk This usually being indicative of cerebellar involvement
Tremor
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Diffuse diseases of the cerebrum, cerebellum, spinal cord Degenerative nervous system disease e.g. hypomyelinogenesis Toxic nervous system disease caused by a large number of poisons, Clostridium botulinum toxin in shaker foal syndrome; hyperkalemic periodic paralysis in the horse early stages of hypocalcemia in the cow (fasciculations of the eyelids and ears)
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Spasmodic twitching movements made at much longer intervals than in
tremor, the intervals being usually at least several seconds in duration Easily visible Caused by muscles that are ordinarily under voluntary control. May occur after traumatic injury to a spinal nerve
Tics
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other name is backward tone a continuous spasm of the neck and limb muscles resulting in dorsal and
caudal extension of the head and neck with rigid extension of the limbs
Opisthotonos
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Tetanus is a continuous contraction of muscles without tremor Most com mon cause is Clostridium tetani intoxi cation The degree of muscular contraction can be exaggerated by stimu lation of the
affected animal and the limbs are rigid and cannot be passively flexed easily
Tetany
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Brief, intermittent tetanic contraction of the skeletal muscles that results in
the entire body being rigid for several seconds, followed by relaxa tion Inherited congenital myoclonus Horned and crossbred Hereford calves Entire body becomes rigid for 10-15 seconds
Myoclonus
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Violent muscular contractions affecting part or all of the body and occurring
for relatively short periods The convulsion may be clonic or tonic (clonic): the typical 'paddling' involuntary movement in which repeated muscle
spasms alternate with periods of relaxation (tonic): less common and are manifested by prolonged muscular spasm without
intervening periods of relaxation occur only rarely and chiefly in strychnine poisoning and in tetanus
Convulsions can originate from disturb ances anywhere in the prosencephalon, including cerebrum, thalamus or hypothalamus
Con vulsions are often subdivided into intracranial and extracranial
Convulsions(seizures,fits,ictus)
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Intracranial convulsions Encephalomyelitis Meningitis Encephalomalacia Acute brain edema Brain ischemia, including increased intracranial pressure Local lesions caused by trauma ,abscess tumor, parasitic injury, Hemorrhage Inherited idiopathic epilepsy.
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Extracranial convulsions Brain hypoxia, as in acute circulatory or cardiac failure Toxic and metabolic diseases of the nervous system , including: Hepatic encephalopathy Hypoglycemia Hypomagnesaemia Congenital and inherited defects convulsions and ataxia in Angus cattle
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Involuntary , intermittent contractions of large muscle masses may result
in spas modic movements of individual limbs or parts of the body Stringhalt and Australian stringhalt of horses Inherited spastic paresis of cattle Inherited periodic spasticity of cattle Inherited congenital myotonia of cattle Inherited myotonia of goats
Involuntaryspasticparesis
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