Neuro 2 Flashcards
What neurons [4 locations] are involved in discriminitive touch/proprioception/vibration pathway?
posterior root ganglia, nucleus gracilis/cuneatus, VPL thalamus, postecentral gyrus
Where does the posterior column/medial lemniscus pathway decussate?
rostral medulla [internal arcuate fibers]
Signs of injury to posterior columns in spinal cord?
IL loss of discriminitive touch, proprioception and vibration
Signs of injury to medial lemniscus?
CL loss of discriminitive touch, proprioception and vibration
What is the Romberg test?
test of proprioceptive function [NOT cerebellum]; pt stands upright with arms abducted eyes open vs. eyes closed
What indicates a positive Romberg test indicate?
a marked difference in the ability to maintain erect posture with eyes open vs. eyes closed = + Romberg
What does a Romberg test look like in someone with cerebellar injury?
with cerebellar injury, pt cannot stand up even with eyes open - DON’T DO A ROMBERG TEST in a pt with cerebellar injury
Neurons [4 locations] in pain/temperature pathway?
posterior root ganglia, posterior horn, VPL thalamus, postcentral gyrus
Where does the spinothalamic tract decussate?
anterior white commissure, spinal cord, all levels
Deficits in syringomyelia?
BL dermatomal loss of pain and temperature [usually upper limbs]
Cause and signs of Dejerine-Roussy syndrome?
Extreme hypersensitivity to painful stimuli following posterior thalamic infarct
What is the function of lower motor neurons?
innervate skeletal muscle
Location of lower motor neurons?
spinal cord + motor cranial nerve nuclei (III, IV, V, VI, VII, IX, X, XI, XII)
Location of upper motor neurons?
cerebral cortex, red nucleus, reticular formation
Signs of injury to Upper Motor Neuron (UMN)?
hemiparesis, increase muscle stretch reflexes [hyper-reflexia], spasticity, clonus + Babinski sign, Hoffman sign
Lower motor neuron (LMN) signs?
paralysis, decreased muscles stretch reflexes [hyporeflexia], flaccid tone, atrophy
Motor tracts in the posterior limb of the internal capsule?
corticospinal [upper limb, trunk, lower limb]
What is spasticity?
a velocity-dependant increase in muscle tone [injury to UMNs]
What is rigidity?
a velocity-independant increase in muscle tone [damage to Basal Nuclei structures]
The corticospinal tract decussates at what level?
pyramidal decussation, caudal medulla
Motor tracts in the genu of the internal capsule?
corticobulbar [to cranial nerve nuclei]
Signs of injury to the corticospinal tract in the right internal capsule?
left, UMN signs
Signs of injury to the corticospinal tract in cervical spinal cord on the right?
right, UMN signs
Signs of injury to the corticobulbar tract in the right internal capsule?
left, lower facial paralysis; tongue points away from lesion
Location of lesion in decorticate posturing?
rostral midbrain or thalamus - red nucleus intact
Location of lesion in decerebrate posturing?
midbrain - damage involving red nucleus or rubrospinal tract
Signs of myopathy?
proximal symmetric weakness, no sensory loss
What are the 2 most common causes of peripheral neuropathies?
diabetes, alcoholism
Signs of polyneuropathy?
stocking/glove sensory loss
Neurons in auditory pathway [at least 6]?
spiral ganglion, cochlear nucleus, superior olive, inferior colliculus, medial geniculate, primary auditory cortex
Result of Rinne test in normal ear?
air conduction > bone conduction
Result of Rinne test in conductive hearing loss?
air conduction < bone conduction
Result of Rinne test in sensorineuronal hearing loss?
air conduction > bone conduction
Result of Weber test in normal hearing?
localize to midline
Result of Weber test with sensorineuronal hearing loss in R ear?
localize to left
Result of Weber test with conductive hearing loss R ear?
localize to right [You can verify this by sticking your finger in your ear and performing the Weber test on yourself.]
Deficits with injury to CN VIII?
IL deafness, dizziness, CL nystagmus
Deficits with injury to brainstem auditory pathways?
bilateral hearing loss
What is presbycusis?
age-related hearing loss, high frequencies lost first
Neurons in visual pathway [3 neurons]?
retinal ganglion cells, lateral geniculate, primary visual cortex
Signs of injury to optic nerve/retina?
IL visual loss, can affect both temporal and nasal hemifield
Signs of injury to optic chiasm?
bitemporal hemianopsia
Signs of injury to optic tract?
contralateral homonymous hemianopsia
Signs of injury to Meyer’s loop?
upper quadrant homonymous hemianopsia
Visual deficits in PCA stroke affecting calcarine sulcus?
contralateral homonymous hemianopsia, with macular sparring
What is Marcus Gunn pupil?
optic nerve lesion, when light is shown into bad eye, pupil dilates (bad retina = no light)
What structures comprise the basal ganglia [nuclei]?
caudate, putamen, globus pallidus, subthalamic nucleus, basal nucleus of Meynert
Brain region affected in Parkinson disease?
substantia nigra, pars compacta [dopamine]
Signs of Parkinson disease?
bradykinesia, pill-rolling tremor, masked facies, postural instability
Pathological sign of Parkinson disease?
Loss of dopaminergic neurons in SN + Lewy bodies in SN
Brain region affected in Huntington disease?
caudate nucleus
Signs of Huntington disease?
choreioform movements, dementia
Brain region injured in right hemiballismus?
left subthalamic nucleus
Signs of essential tremor?
chronic, progressive tremor in arms, neck, larynx, chin; reduced with alcohol consumption
What is Wilson disease?
inborn error of copper metabolism; Kayser-Fleischer rings; wing-beating tremor, rigidity
What are signs of cerebellar injury?
ataxia, dysmetria, dysdiadokinesia, nystagmus, dysarthria
Signs of injury to vestibulocerebellum (flocculonodular lobe)?
truncal ataxia, nystagmus
Signs of injury to lateral hemisphere of cerebellum?
IL limb ataxia, intention tremor, dysarthria
Signs of injury to middle cerebellar peduncle?
IL limb ataxia
Results of caloric testing in normal individual?
COWS - cold = nystagmus to opposite side; warm = nystagmus to same side
Signs of Arnold-Chiari I malformation?
extension of cerebellar tonsil below foramen magnum
Signs of Arnold-Chiari II malformation?
displaced vermis + myelomeningiocele
Signs of Dandy-Walker?
enlarged posterior fossa, small cerebellum, absent vermis, cystic dilation of 4th ventricle, hydrocephalus
