Lecture: Neurolocalization Flashcards
Brain and Cranial nerves
- Forebrain
- Cerebrum: I
- Diencephalon: II
- Cerebellum
- Brainstem
- Midbrain: III-IV
- Pons: V
- Medulla oblongata: VI-XII
Forebrain
INHIBITORY
CS
- Seizures
- Circling
- Compulsion
- Behavior changes
- inappropriate
- getting stuck in corners
- Blindness (amaurosis)
- Postural reaction deficits
- Gaint should be normal
Amaurosis
Non-ocular blindness
Horner’s Syndrome
Loss of sympathetic innervation to eye
CS
- Ptosis
- Prolapsed 3rd eyelid
- Miosis
- Enopthalmos
*Horses with Horner’s are hyperthermic and sweat unilaterally
Cerebellum Signs
- Intention tremors
- Head tilt
- Nystagmus
- Loss of menace
- Truncal sway
- Ataxia
- Hypermetria
NOT Cerebellar signs
- Paresis
- Behavior changes
- CP deficits
Cerebellar Ataxia
- Hypermetria
- ‘spastic’
- NO PARESIS
Brainstem Signs
- Decreased mentation (ARAS)
- reticular activating system runs through brainstem
- obtunded to stuporous to comatose
- CN deficits
- Usually some CN VIII involvement
- Check for physiologic nystagmus
Brainstem: Gait
- Vestibular or proprioceptive ataxia
- if ambulatory
- may seem cerebellar depending on lesion
- Tetraparesis (will always be seen w/ brainstem lesions)
- Proprioceptive deficits
Neurolocalization: Spine
- C1-C5: All 4 limbs (equally affected)
- C6-T2: All 4 limbs (thoracic [LMN] different to pelvic [UMN] limbs)
- T3-L3: Only pelvic limbs affected
- L4-S3: Only pelvic limbs affected (LMN)
Segmental Reflexes
- Can sever spinal cord cranial or caudal to the intumescense and reflex will still be intact
Withdrawel reflex is NOT
Conscious
Extended, difficult to flex limb
Implies UMN lesion
Flaccid, unable to support any weight
- Implies LMN involvement
- Consider spinal shock
Localization: C1-C5
- +/- ambulatory
- knuckling, stumbling, ‘face-planting’
- Tetraparesis
- Ataxia
- TL signs more subtle than PL
- Reflexes: N to inc on all limbs
- +/- muscle fasciculations
- +/- Pain
Localization: C6-T2
- +/- ambulatory
- knuckling, stumbling, ‘face-planting’
- ‘two-engine’ gait
- Tetraparesis
- Ataxia
- Reflexes
- TL: N to dec
- PL: N to inc
- +/- muscle fasciculations
- +/- Pain
Localization: T3-L3
Classic Dachshund
- +/- ambulatory
- Paraparesis
- increased PL tone
- PL ataxia
- +/- Kyphosis
- Reflexes:
- TL: N
- PL: N to inc
- +/- Panniculus cut-off
- +/- pain
- usually painful
Kyphosis
hunched back
Spinal shock
- Not prognostic
- Localization T3-L3
- Physiologic or anatomic transection of spinal cord
- causes temporary loss or depression in muscle tone and spinal reflex below injury
- associated with acute injury
- Patellars return within hours in dogs
- Withdrawel can take days to return
Schiff-Sherrington posture
- Not prognostic
- Localization to T3-L3
- Extensor hypertonia of TLs
- due to loss of ascending inhibition
- Associated with severe TL lesions
- plegia +/- pain perception
- Distinguish from decerebrate and decerebellate postures
- mentation, CNs
Localization: L4-S3
- +/- Ambulatory
- PL Ataxia
- +/- pain
- Paraparesis
- Decreased PL muscle tone
- Reflexes
- TL: N
- PL: dec to absent
- +/- panniculus to cut-off
- Anal tone?
- Perineal reflex?
- Tain tone?
- Tail sensation?
Localization: LMN
- +/- ambulatory
- NO ATAXIA
- NO PAIN
- +/- CN weakness
- gag, facial
- Paresis
- decreased muscle tone all over
- Reflexes
- dec to absent
- +/- panniculus affect
- Exercise intolerance
- hallmark for myasthenia gravis
DDX
Chondrodystrophoid
- IVDD
DDX
Acute non-progressive
- Vascular
- Trauma
- IVDD
DDX
Acute Progressive
- Trauma
- IVDD
- Neoplasia
- Inflammatory
- Infectious
DDX
Chronic progressive
- Neoplasia
- Degenerative
- IVDD
- Inflammatory
- Infectious
There are no nerve endings within
Spinal cord
Painful spinal lesions
- IVDD
- Meningitis/meningomyelitis
- Diskospondylitis
- Fracture/luxation
- Neoplasia (bone)
