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94 Cards in this Set
- Front
- Back
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What do the Ascending fibers conduct? |
Afferent information that might or not might make consciousness |
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What are the 7 Ascending Fibers?
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1. Lateral Spinothalmic tract 2. Anterior Spinothalmic Tract 3. Dorsal column pathways 4. Anterior/Posterior Spinocerebellar Tract 5. Spinotectal Tracts 6. Spinoreticular tract 7. Spino-olivary tract |
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Whats the function of the Lateral spinothalmic tract? |
To send pain and temperature |
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Origin of Lateral spinothalmic tract? Fibers used? Pathway |
Pain and thermal impulses from free nerve endings Fast A-Delta and slow C fibers form the Posterolateral tract of Lissauer, synapses contralaterally in spinal segment |
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What is the function of the Anterior Spinothalmic Tract? |
Light/crude touch light pressure |
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What is the function of the Dorsal column pathways? |
Two point discrimination vibration muscle/joint movement Proprioception |
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What is the function of the Anterior/Posterior Spinocerebellar tracts? |
To send Unconscious information from muscles, joints and skin to the cerebellum |
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What is the function of the Spinotectal tract? |
To send Pain, thermal, and tactile information to the superior colliculus of the midbrain for spinovisual reflexes |
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What is the function of the Spinoreticular tract? |
To send information from Muscle, joint and skin |
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What is the function of Spino-olivary tract? |
an indirect pathway for get afferent info into the cerebellum |
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What if the Lateral Spinothalmic tract is injured? |
Contralateral loss of Pain and thermal sensibilities below the level of injury |
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Postcentral gyrus |
Interprets past experienced pain |
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Cingulate gyrus |
Interprets emotional part of pain |
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Insular gyrus |
Interprets visceral pain and autonomic responses |
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Anterior Spinothalmic pathway |
Contralateral at spinal segment |
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Injury to the Anterior Spinothalmic tract? |
Contralateral loss of light touch and Pressure |
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Anterior Spinocerebellar pathway |
Contralateral into the cerebellum (Majority) |
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Posterior Spinocerebellar Pathway |
synapse on Clark's column and continue Ipsilaterally (same side) to Medulla and inferior peduncle into the cerebellar cortex |
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Dorsal column pathways |
Fascicles cuneatus --> upper thoracic and cervical Fascicles gracilis --> Lower thoracic, sacral, lumbar Both cross (decussation) at medulla oblongata |
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What are the Descending tracts? |
1. Corticospinal Tract 2. Reticulospinal tract 3. Tectospinal tract 4. Rubrospinal Tract 5. Vesibulospinal Tract 6. Olivospinal Tract 7. Descending Autonomic Fibers |
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Function of corticospinal Tract |
voluntary, skilled movements especially in the distal part of limbs |
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Function of Reticulospinal tracts |
Activate or Inhibit Alpha and Gamma Motor neurons in the anterior spinal cord → Facilitate or inhibit voluntary movements or relexes |
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Function of Tectospinal tract |
Reflexive Head movements in response to visual stimuli. Also involve Sympathetic → pupil dilation reflex in the darkness |
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Function of Rubrospinal tract |
Act on alpha and gamma motor neurons in spinal cord → activate flexor muscles and Inhibit extensor muscles |
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Function of Vestibulospinal Tract |
Acts on motor neurons in spinal cord → Activate activity of extensor and Inhibits flexor muscle OPPOSITE OF RUBROSPINAL TRACT |
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Function of Olivospinal tract |
May not exist. May play a role in muscle activity |
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Descending Autonomic fibers |
controlling visceral activity |
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Corticospinal (Pyramidal) Tract Origin? Site of Crossover? Destination? Branches to? |
PYRAMIDAL CELLS → Primary motor cortex (Area 4), Secondary motor cortex (Area 6), and Parietal Lobe (Areas 1, 2, 3) Most cross pyramids and descend laterally or minority cross at destination Internucial neurons or alpha motor neurons Cerebral cortex, basal nuclei, red nucleus, olivary nuclei, and reticular formation |
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Reticulospinal Tracts Origin? site of crossover? Destination? Branches to? |
Reticular formation Crossing at various levels Alpha and Gamma Motor Neurons Multiple branches as they descend |
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Tectospinal tract Origin? Site of crossover? Destination? |
Superior colliculus Soon after origin Alpha and Gamma Motor neurons |
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Rubrospinal Tract Origin? Site of Crossover? Destination? |
Red Nucleus Immediately Alpha and Gamma Motor Neurons |
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Vesibulospinal tract Origin? Site of Crossover? Destination? |
Vestibular Nuclei DOESN'T CROSS. Alpha and Gamma Motor Neurons |
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Olivospinal Tract Origin? Site of Crossover? Destination? |
Inferiror Olivary Nuclei Unknown Alpha and Gamma Motor Neurons |
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Descending Autonomic fibers Origin? Site of Crossover? Destination? |
Cerebral cortex, hypothalamus, amygdaloid complex, reticular formation Crosses at the Brainstem Sympathetic and Parasympathetic Outflows |
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Crossed extensor reflex |
A reflex on one side of the body has an opposite effect on the other side |
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Law of Reciprocal innervation |
Flexors and Extensors cannot contract simultaniously What blocks it? → Afferent fiber responsible for flexor muscles have branches that synapse with extensor motor neurons of the same limb... causing inhibition |
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Inhibitory Neurotransmitters |
GABA and Glycine |
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Renshaw cells and Lower Motor Neuron Inhibition |
Lower motor nueorns have axons that synapse on Renshaw cells that resynapse themselves on the lower motor neuron to inhibit them therefore, causing inhibition... kind of like a circle except the other side inhibits the origin of the signal |
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Decebrate rigidity |
After spinal shock, when segmental spinal reflexes are depressed, dissapears the reflexes return and muscle tone is increased. Due to overactivity of gamma efferent nerves |
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Paraplegia of extensors |
Hypotonia of extensors, causing dominance of the flexors this is due to the descending tract only partially severed |
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Visceral pain Sx |
usually Referred pain → Px distant from organ involved causes nausea, vomiting, tachycardia and sweating |
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Coricospinal tract is clinically referred to as the.... |
Pyramidal tract |
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Extrapyramidal tracts refers to... |
ALL other tracts other than corticospinal tract |
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Babinski's Sign |
Scratching sole of the lateral foot Normal: Plantar flexion (+) Babinski: toe becomes dorsally flexed and others fan outward |
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What are the signs of Lesions of the Pyramidal tract? |
1. (+) Babinski's sign 2. Absent superficial abdominal reflexes 3. Absent Cremaster reflex 4. Loss of voluntary movements especially at distal end of limbs |
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What are the signs of Lesions to the Extrapyramidal tracts? |
1. Sever muscle paralysis 2. spasticity 3. Exaggerated deep muscle reflexes 4. Clasp-knife reaction |
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What are the signs of Lower motor neuron lesions? |
1. Flaccid paralysis of muscles 2. Atrophy of Muscles 3. Muscular fasciculation (muscle twitching) 4. Muscular Contracture (stiffness of muscles) 5. Reaction of degeneration → muscle doesnt respond to stimuli days after the lesion |
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Types of Paralysis |
1. Hemiplagia → paralysis of one side of the body (Upper and Lower limbs and trunk) 2. Monoplegia → paralysis of one limb 3. Diplegia → Paralysis of 2 limbs 4. Quadriplegia → paralysis of all 4 limbs |
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Complete Cord Transection can result in.... |
1. Death → between C1 and C3 (breathing) 2. Quadriplegia → btw C4 and C5 3. Respiratory paralysis → Above C5 4. Paraplegia → Below T1 5. Complete loss of all sensibility (complete anesthesia) below level of lesion 6. Complete loss of all voluntary movement (spastic paralysis) below level of lesion 7. Urinary and fecal incontinence (Reflex emptying can happen) 8. Autonomic disturbances |
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Anterior cord syndrome is caused by ..... |
Occlusion of the anterior spinal artery or Fracture dislocation of vertebrae |
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Anterior cord syndrome can result in... |
1. bilateral lower motor neuron damage (flaccid paralysis and Areflexia) at level of lesion 2. bilateral spastic paralysis (damage to corticospinal tract) below the level of lesion 3. Bilateral loss of pain, temperature, and light touch below the level of lesion Dorsal column pathways are undamaged! (2 point discrimination and vibration) |
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Central cord syndrome is caused by... |
Hyperextension of the cervical spine and compression of the spinal cord |
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Central cord syndrome results in.... |
1. Bilateral lower motor neuron damage (flaccid paralysis and Areflexia) at the level of the lesion 2. Bilateral Spastic paralysis (Damage to corticospinal tract) below the level of the lesion with characteristic sacral sparing 3. Bilateral loss of pain, temperature, and light touch below the level of lesion with characterisic sacral sparing (anal region is sparred) |
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Brown sequard syndrome, also known as.... |
Hemisection of the spinal cord |
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Brown Sequard syndrome/Hemisection of the spinal cord... results in.... |
1. Ipsilateral lower motor neuron (flaccid) paralysis in the segment of the lesion 2. Ipsilateral spastic paralysis below the level of the lesion (Lateral Corticospinal tract), (+) Babinski's sign 3. Ipsilateral loss of tactile discrimination, position and vibration (dorsal white column) 4. Ipsilateral anesthesia at the level of injury (Dorsal horn destruction) 5. Contralateral loss of pain and temperature senses below the injury level (Lateral Spinothalamic tract) 6. Contralateral (but not complete) loss of crude tough (Anterior spinothalamic tract) |
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Poliomyelitis results in.... |
1. Acute viral infection of the Anterior neurons of the spinal cord and motor nuclei of cranial nerves causing muscle paralysis 2. Suppressed immune system 3. Death of motor neuron and muscle paralysis, especially of the lower limb 4. Paralysis of the diaphragm and intercostal muscles → no respiration 5. Improved at the end of first week of infection since there's less edema in the affected area → function returns |
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Lou Gehrig's disease is also known as.... |
Amotrophic Lateral Sclerosis |
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Amylotrophic Lateral Sclerosis/Lou Gehrig's disease results in.... |
Destruction of corticospinal tracts (Upper motor Neurons) and the Lower motor neurons
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More Lou Gehrig's disease facts... |
1. Familial in 10% of cases 2. Occurs in Middle age (50-70 year olds) 3. happens to males more 2:1 4. Lethal within 2-6 years |
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What are the Lou Gehrig's Disease signs in Upper motor neurons and Lower motor neurons |
UMN: Paresis, Spasticity and (+) Babinski's sign LMN: progressive muscular atrophy, paresis, muscle fasciculation |
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Syringomyelia is.... |
A developmental abnormality in the formation of the central canal. Usually in the brainstem and the cervical spinal cord. |
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Syringomyelia results in .... |
1. Central cavitation 2. Gliosis 3. Bilateral loss of pain and temperature (Lateral Spinothalmic tract) 4. Ventral horn involvement (LMN injury) → causing muscle wasting (Lumbricals and interosseous muscles of the hand) 5. Involvement of lateral horn or lateral funiculus can affect descending sympathetic tract 6. Lateral funiculus involvement (Lateral corticospinal tract) results in spastic paresis |
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What are the demyelinating diseases of the CNS? |
Multiple Sclerosis and Vitamin B12 neuropathy |
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Multiple Sclerosis |
1. most common form of demyelinating disease 2. Asymmetric lesions can effect all tracts of the spinal cord 3. Most commonly occurs in cervical segments and also in the brain 4. Primary Axonal transection or as a result of multiple demyelination leads to motor and sensory disturbances |
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Vitamin B12 Neuropathy |
1. results from Vitamin B12 deficiency (Pernicious anemia) 2. Demyelination of: Dorsum column pathways, spinocerebellar tracts, and Corticospinal tracts |
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Abnormalities in sensory perception |
Hypalgesia → diminished pain sensation Hypesthesia → diminished touch sensation Hyperesthesia → Heightened touch sensation Paraesthesia → Abnormal sensations |
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Phantom Limb |
After amputation of a limb → patient might feel severe pain from the pressure of nerve fibers at the end of the stump |
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How many and where are the spinal cord swellings?
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spinal cord swellings = Intumiscentia there are 2 and are found at: Cervical Intumiscentia (C4-T1) Lumbar Intumiscentia (T11-T1) |
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What produces CSF and what foramen does it go through to get into the Subarachnoid space? |
Choroid Plexus produces CSF goes through Foramen Luschka x2 and Foramen Magendie |
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Characteristics of CSF Appearance? Normal Pressure? |
Clear and Colorless 60-200mm of water |
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Where is CSF absorbed? |
through Arachnoid granulations into the venous sinuses |
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Where do the vertebral arteries pass through? |
pass through the transverse foramen of the 6 upper cervical vertebrate and enter the Foramen magnum |
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What is the biggest segmental artery? |
Adamkiewicz artery found anteriorly |
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What is the spinal cord blood supply? |
Anterior spinal Artery (2/3 supply) (Narrowest at T8) Two posterior arteries (1/3 supply) and Segmental arteries which are regional Segmental arteries → branch to Radicular arteries |
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Thoracic Aortic Dissection |
Caused by a weak wall of aorta secondary to degenerative disease creates a bag of blood on aorta in the "Media layer" the "Intima layer" is broken |
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Occlusion of the Anterior spinal artery causes.... |
1. Damage to Corticospinal tract → Paraglegia, loss of motor function 2. Anterior grey horn damage → Weakness of limb muscles 3. Damage to descending autonomic tract → Loss of bladder and bowel control 4. Spinothalmic damage → bilateral thermoanesthesia Proprioception, vibration, and light touch are normal! |
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Largest bundle of white matter? As you go down the spinal cord...? |
Corpus Collosum White matter decreases and grey matter increases |
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Grey matter consists of.... The Anterior horn has what cells? |
Neurons, glial cells and blood vessels Alpha-motor neurons and Gamma-motor neurons |
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The posterior horn has what cells? |
Substantia Gelatinosa of Rolando → receives touch, pain, and temperature afferents Nucleus Proprius → Receives Proprioception fibers Clark's Nucleus → (C8-L3/4) receives proprioceptive fibers visceral afferent Nucleus → (T1-L2/3) Sympathetic chain Lateral Grey horn sympathetic neurons → (T1-L2/3) Sympathetic chain |
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During the Ascending tracts, what sensations crosses where? |
Pain, Temperature, and coarse touch → midline of the spinal cord Fine touch, vibration, and Proprioception → Medulla Oblangata |
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Primary or First order Neurons Second Order Neurons Third Order Neurons |
1st order → Enter at dorsal horn level and/or ascend in the dorsal column 2nd Order → Synapses with 1st Order neurons and CROSS. Ascend into the thalamus 3rd Order → Synapses with 2nd Order Neurons and goes to sensory region of cerebral cortex |
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What are the Main excitatory NT for pain? |
Fast → Glutamate Slow → Substance P |
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Pain Perception takes place at... Fast Pain is caused by _____ Fibers Slow pain is caused by _____ Fibers |
Free Nerve endings Fast Pain is causedby A-Delta Fibers Slow Pain is caused by small diameter C fibers |
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Gate theory of Pain |
Dampening a Pain signal, by using another signal to diminish it or eradicate it |
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The analgesia system |
Stimulating certain areas of the brainstem can reduce or block pain |
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How do you treat acute pain? |
Salicylates (asprin) → reduce synthesis of prostagladin Local anesthetics → block nerve conduction in PNS narcotic Analgesics → Reduce effective reasion to pain in CNS |
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Pain relief: Rhizotomy Cordotomy |
Posteriror Rhizotomy → Transcetion of the Dorsal root of one or more spinal nerves transmitting pain. Other sensations can be lost Thoracic or Cervical Cordotomy → cutting lateral spinothalmic fibers of opposite side of abdominal or pelvic or cervical region pain |
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Trigeminal neuralgia: Also called..... |
Tic Douloureux Which is → Unilateral pain of the face in one or more division of the trigeminal nerve |
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Symptoms of Trigeminal Neuralgia |
Unilateral stabbing pain none/minimal sensory loss In a different area of the face from trigger point Sudden onset and pain free intervals Pain restricted to CNV (Mainly), CNVII, CNIX, and CNX |
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Pathogenesis of Trigeminal neuralgia |
Segmental demyelination and Artificial synapse formation at the junction of central and peripheral myelin → causing short circuit with triggers switching it on |
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causes of Trigeminal Neuralgia |
-Mechanical compression of Trigeminal N (at Pons) -1st Division Pain → Inferior posterior cerebellar, vertebral or inferior anterior cerebellar artery compression -2nd or 3rd trigeminal division pain → Compression from superior Cerebellar artery |
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Therapy for Trigeminal Neuralgia |
1. Pharmacologic 2. Local Anesthetic Block 3. Neurolytic Block with Alcohol 4. Dental Procedures 5. Surgical therapies → Rhizotomies |
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What is Gangliolysis? |
Destroying a ganglion Treatment for Trigminal Neuralgia → placing a needle through the cheek through foramen Ovale into cistern of Trigeminal Ganglia |
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chances of Pain relief with Glycerol Gangliolysis for Trigeminal Neuralgia |
80% → of 1 year of pain relief 60% → of 5 years of pain relief |
