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| | [[Neurological Examination of Horses Overview]] | | [[Neurological Examination of Horses Overview]] |
| − | ===Aims of Neurological Examination===
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| − | * There are two main aims of neurological examination:
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| − | *# To aid determination of the presence or absence of neurological disease.
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| − | *# To localise the lesion(s) when neurological disease is suspected.
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| − | ===Indications for Neurological Examination===
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| − | * Neurological testing may be indicated by:
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| − | *# '''History'''
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| − | *#* For example, the owner reports a seizure-like episode.
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| − | *# '''Clinical examination'''
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| − | *#* For example, an unexplained area of muscle atrophy or patchy sweating.
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| − | *# '''Information from other tests'''
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| − | *#* Particularly negative, confusing or corroborating evidence from these.
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| − | *#* For example:
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| − | *#** A horse evaluated for pelvic limb lameness that may in fact have a neurological problem.
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| − | *#** A horse with altered mentation or depression that has already been found to have abnormal hepatic function.
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| − | ===Approaches to Neurological Examination===
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| − | * A methodical approach is necessary, whatever the background, to ensure no aspect of examination is omitted.
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| − | * Two different approaches may be taken:
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| − | *# '''Systems based'''
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| − | *#* The different neurological modalities of the systems are examined in turn.
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| − | *# '''Anatomic'''
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| − | *#* Tests are performed in turn working from head to tail.
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| − | * A combination of the two approaches tends to be used in practice.
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| − | ==Neuroanatomy==
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| − | * Certain basic facts must be understood before a decent neurological examination may be performed.
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| − | ===White and Grey Matter===
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| − | * '''White matter''' consists of myelinated axons of nerve cells.
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| − | * '''Grey matter''' is made up of neuronal cell bodies, containing the nucleus.
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| − | ===Afferent and Efferent===
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| − | * '''Afferent''' pathways relay sensory information from receptors towards the spinal cord or brain.
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| − | ** For example:
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| − | *** Touch
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| − | *** Muscle stretch
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| − | *** Vision
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| − | *** Balance
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| − | * '''Efferent''' pathways relay motor or effector information from the brain or spinal cord to muscles or organs.
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| − |
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| − | ===Motor Neurons and Motor Reflexes===
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| − | * '''Lower motor neurons''' are the last link in the efferent pathway.
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| − | ** Directly innervate skeletal muscles.
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| − | ** Cell bodies are located in the ventral horn of the grey matter of the spinal cord.
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| − | ** Their axons run in peripheral nerves and synapse at the neuromuscular junction.
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| − | * '''Upper motor neurons''' communicate with lower motor neurons.
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| − | ** They:
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| − | *** Relay information to lower motor neurons
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| − | *** Control the output of lower motor neurons.
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| − | ** Upper motor neurons are found in the brain and spinal cord.
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| − | * The term '''reflex''' describes a certain sort of nervous pathway.
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| − | ** The sequence of events in a reflex is as follows:
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| − | **# Signals are derived from receptors.
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| − | **#* For example, tendon stretch.
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| − | **# Signals are conveyed directly in sensory (afferent) fibres.
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| − | **# Afferent signals reach the central nervous system.
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| − | **# Effector signals are generated in the CNS.
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| − | **#* This generally occues via an intermediate neuron, known as the internuncial neuron.
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| − | **# Effector signals are relayed in the lower motor neurons to the muscles.
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| − | ** A reflex does NOT require:
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| − | *** Conscious perception of the stimulus
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| − | *** Ascending or descending upper motor neuron pathways
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| − | *** Ascending or descending proprioceptive pathways
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| − | [[Category:Neurological Examination - Horse]]
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| | [[Neurological Examination Initial Observation - Horse|A]] | | [[Neurological Examination Initial Observation - Horse|A]] |