ClinNeuro- Localizing Lesions

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  1. Steps for localization of a lesion in the spinal cord. (6)
    • 1- gait and posture
    • 2- postural reactions
    • 3- pelvic limb tone and reflexes
    • 4- thoracic limb tone and reflexes
    • 5- cutaneous trunci reflex
    • 6- spinal palpation
  2. Conscious proprioceptive deficits in both pelvic limbs; the lesion is _________.
    caudal to T2
  3. When ataxia is present, crossing is a sign of ___________.
    proprioceptive deficit
  4. What spinal cord segment is this?
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  5. What spinal cord segment is this?
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    Thoracic; lateral grey column is unique to TL region
  6. What spinal cord segment is this?
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  7. What spinal cord segment is this?
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    Sacral; cauda equina
  8. Proprioceptive ataxia is a sign of damage to the ____________.
    spinocerebellar tract
  9. Describe the sequence of appearance of signs in compressive spinal cord lesions. (4)
    proprioceptive ataxia with mild paresis--> ataxia with severe paresis--> paralysis and urinary incontinence--> loss of nociception
  10. Conscious proprioception is a ________ pathway than the nociception pathway, which is __(3)__; therefore,...
    simpler; complex, highly resistant, and multi-synaptic; to damage the nociception system requires a severe spinal cord injury.
  11. Define a LMN.
    originates in the cervical or lumbar intumescence in the spinal cord and innervates muscles in the limbs; consider a peripheral n.
  12. Define an UMN.
    Start in the brain and stay within the spinal cord
  13. Pool of neurons in the brain that go down in the spinal cord to influence the LMNs.
  14. What are the functions of UMNs? (5)
    initiate voluntary movements, postural adjustment, maintenance of muscle tone, stimulate flexor mm., inhibit extensor mm.
  15. Clinical signs of lesions affecting UMNs. (3)
    paresis/paralysis, normal to increased muscle tone and reflexes, mild muscular atrophy
  16. Describe the pathway of a LMN, along which any lesions will cause LMN dysfunction signs.
    motor neuron in ventral grey column of spinal cord--> nerve root--> spinal nerve--> peripheral n.--> target muscle
  17. What are the functions of LMNs? (3)
    Final common pathway, manifest motor activity that is voluntary and reflexes
  18. Clinical signs of LMN dysfunction.
    paresis/paralysis, decreased to absent muscle tone and reflexes, severe muscular atrophy
  19. With a combined UMN and LMN injury, the ______ signs will always prevail b/c it is the ___________.
    LMN; final common pathway
  20. Describe signs associated with lesions in each region of the spinal cord.
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    • C1-C5- TL UMN, PL UMN
    • C6-T2- TL LMN, PL UMN
    • T3-L3- PL UMN
    • L4-S3- PL LMN
  21. The dog can't move any of it's limbs; where is the lesion possibly located? How can you differentiate it?
    lesion is either C1-C5 or C6-T2; C1-C5 UMN signs in both PL and TL; C6-T2 LMN TL and UMN PL
  22. Under what circumstances will you see LMN signs?
    only if the lesion is in the C6-T2 or L4-S3 regions, where the brachial plexus and lumbosacral plexus come from, respectively
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  24. Spinal cord lesions in motor tracts are always __________.
  25. Ataxia, tetraparesis, reflexes normal to increased in all limbs; where is the lesion?
  26. Ataxia, tetraparesis/plegia, decreased/absent reflexes in thoracic limbs, normal to increased reflexes in pelvic limbs; where is the lesion?
  27. Ataxia, paraparesis/plegia, normal to increased reflexes in the pelvic limb; where is the lesion?
  28. Mild ataxia, paraparesis/plegia, decreased to absent reflexes in the pelvic limbs; where is the lesion?
  29. C6-C8 is an important subdivision that is associated with ___________; what signs would be associated with this disorder? (5)
    Wobbler's Syndrome; pelvic limb ataxia, spastic thoracic limb gait, increased extensor tone in TL, normal or decreased flexor tone in TL, normal to increased tone in PL
  30. In the thoracic limb, everything is a balance between flexion, the _________ nerve in the __________ portion of the brachial plexus, and extension, the __________ nerve in the ___________ portion of the brachial plexus.
    musculocutaneous; cranial; radial; caudal
  31. In what vertebral bodies are the L4-S3 spinal cord segments housed?
    L4 and L5 vertebral bodies
  32. In what vertebral bodies are S1-S3 spinal cord segments housed?
    all in the L5 vertebral body (caudal to this point, cauda equina)
  33. What causes the Schiff-Sherrington Syndrome posture?
    severe lesion in the TL (T2-L5) region
  34. What is the Schiff-Sherrington Syndrome posture?
    ONLY WHEN THE DOG IS IN LATERAL RECUMBANCY, increased extensor tone in the TLs (UMN signs); in sternal recumbency, TLs are normal
  35. With Schiff-Sherrington, there is damage to the ___________.
    propriospinal tract
  36. To further localize a T3-L3 lesion, what two tests do you use?
    cutaneous trunci reflex and or spinal palpation
  37. Crossed externsor reflex/ninja kick indicates...
    UMN lesion and chronicity.
  38. Describe what signs you would see in each if these situations, assuming the red dots are lesions.
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    • 1- LMN TL, UMN PL
    • 2- UMN all 4 limbs; find second lesion by spinal palpation and cutaneous trunci reflex
    • 3- LMN TL, UMN PL;¬†find second lesion by spinal palpation and cutaneous trunci reflex
    • 4- LMN PL
  39. What is the most common presentation, and where is this lesion?
    UMN signs in the PL; T3-L3 myelopathy
  40. What causes LMN signs in the PLs and the TLs?
    lesion is outside the spinal cord- neuropathic, junctional, myopathic, botulism
  41. Diseases that cause LMN signs in all four limbs do NOT  cause ____________.
    proprioceptive ataxia
  42. With brain lesions, what are the 3 possible lesion locations?
    brainstem, cerebellum, thalamocortex (forebrain)
  43. The brainstem contains the ___________, a common site of lesions.
    vestibular system
  44. What signs are associated with brainstem lesions? (2)
    CN deficits and altered mentation
  45. What are the components of the brainstem?
    reticular formation (ARAS), CN III-XII, sensory (ascending) and motor (descending UMN) pathways
  46. Mentation is controlled by the ___________.
    Ascending reticular activating system (reticular formation)
  47. Lesions in the sensory (ascending) and motor (descending UMN) pathways in the brainstem cause __(2)__.
    tetraparesis and ataxia
  48. The ascending reticular activating system maintains a state of ____________; clinical signs of lesions affecting this system include... (3)
    wakefulness; somnolence, stupor, coma
  49. Head tilt indicates a dysfunction in __________, which is a lesion in the __________.
    vestibular function; rostral medulla (CN VIII)
  50. What CN(s) are in the mesencephalon?
    CN III and IV
  51. What CN(s) are within the pons?
    CN V (motor, sensory)
  52. What CN(s) are within the rostral medulla?
    CN V (sensory), VI, VII, VIII
  53. What CN(s) are within the caudal medulla?
  54. What are clinical signs of lesions within the mesencephalon? (3)
    strabismus, ocular paralysis, mydriasis
  55. What are clinical signs of lesions in the pons? (1)
    atrophy of masticatory muscles
  56. What are clinical signs of lesions in the rostral medulla? (3)
    head tilt, facial paralysis, absence of palpebral reflex
  57. What are clinical signs of lesions in the caudal medulla? (4)
    dysphonia, dysphagia, sterterous breathing, tongue paralysis
  58. The more _________ the brainstem lesion in sensory and motor pathways, the less severe the gait abnormalities.
  59. Lesions in the thalamocortex cause __________ deficits.
  60. What is the function of the vestibular system?
    balance and position of eyes, neck, trunk, and limbs
  61. What are the 4 vestibular nuclei in the rostral medulla connected to?
    • cerebellum- projections flocculonoduar lobe
    • reticular formation
    • medial longitudinal fasciculus
    • vestibulospinal tracts
  62. Clinical signs of vestibular disease. (5)
    head tilt, +/- vestibular ataxia, +/- strabismus/nystagmus, somnolence (central lesion), proprioceptive deficits (central lesion)
  63. What part of the vestibular system is associated with motion sickness?
    reticular formation
  64. What part of the vestibular system connects C VIII to CNs II, IV, and VI?
    medial longitudinal fasciulus
  65. How can you differentiate a central and peripheral vestibular lesion?
    central has proprioceptive deficits and somnolence (not peripheral)
  66. Describe nystagmus associated with peripheral vestibular lesions.
    horizontal that goes opposite the head tilt ("running away from the lesion")
  67. Clinical signs associated with cerebellar disease. (8)
    head/body tremors (intentional tremors), ataxia, wide-based stance, truncal sway, dysmetria, hypermetria, ipsilateral absence of menace response, +/- vestibular signs if flocculonodular lobe is involved
  68. With cerebellar disease, there is a(n) ___________ absence of ___________.
    ipsilateral; menace response
  69. What clinical signs should NOT be present if it solely cerebellar disease (no involvement of any other structures)? (2)
    no proprioceptive deficits, no weakness (strength preserved)
  70. Clinical signs of thalamocortex/forebrain disease. (8)
    abnormal behavior, circling, compulsiveness, seizures, central blindness, [contralat. deficits] menace, postural reactions, nasal sensation
  71. With thalamocortical disease, there are __________ deficits in... (3)
    contralateral; menace response, postural reactions, and nasal sensation.
  72. What specific tests can you use to assess thalamocortical function? (4)
    mental status, menace response, nasal sensation, proprioception/hopping
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ClinNeuro- Localizing Lesions
2015-11-13 21:36:03
vetmed clinneuro

vetmed clinneuro
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