clinical neuroanatomy Flashcards
Function of frontal lobes and where in particular is responsible
Motor control: motor strip
Motor planning: premotor cortex
Planning, motivation, behavioural control: pre-frontal
Emotional control: orbitofrontal cortex
Function of parietal lobes
somatosensory function Visuospatial function (right dominant)
Function of temporal lobes
language
Auditory cortex
Memory (hippocampus and medial and temporal lobes)
Amotions (amygdala)
Function of occipital lobes
Visual processing
What is Broca’s area
What will lesions here cause
Lies in front of motor strip at base of frontal lobe
-LEsions in this area cause a non-fluent effortful type speech but with better comprehension
What is Wernicke’s area
What will lesions here cause
sits of top of superior temporal lobe
Fluent speech but paraphasia (speech nonsense) and poor comprehension
What lesion will cause a bitemporal hemianopia
Pituitary macroadenoma lifting chasm
Lesions behind chiasm causing what
Hemianopia
What can cause a hemianopia
Posterior cerebral artery stroke in occipital lobe
If lesions affect only part of the pathway, what can be caused
Quadratantopia
What nuclei are in midbrain and what does midbrain control
3+4 nuclei
vertical eye movements
What nuclei are in pons and what does pons control
6,7 nuclei and horizontal eye movements
What nuclei are in medulla and what does medulla control
vestibular nuclei
10+12 nuclei
respiratory and cardiac centres
Pyramidal decussation
What do lesions in the medial longitudinal fasciculus cause (these are in the midbrain)
intranuclear ophthalmoplegia
What is the motor pathway like (starting from the motor cortex)
Fibres in the motor cortex gather in the corona radiata
Funnel down through internal capsule
Travel down brain stem through the medulla and crosses over to the other side to form the lateral corticospinal tract
What lesions will cause a contralateral hemiparesis and why
lesions in:
1) cortex
2) corona radiata
3) internal capsule
4) pyramidal tract in brainstem
Because this s before there is a crossing over of the motor fibres in the medulla so everything is on the opposite side.
What lesions will cause an ipsilateral hemiparesis and why
Corticospinal tract in lateral spinal cord
This is after the motor fibres have crossed over
which do strokes of the middle cerebral artery and lenticulostriate branches cause
Hemiplegia
what are upper motor neurone
From cortex to corticospinal tract
Why are signs of upper motor neurone disease due to
Hyper-excitability to inputs to anterior horn cells
Signs of upper motor neurone disease
Increased Tone + Clonus
Exaggerated tendon reflexes
Extensor Plantar response
Pyramidal pattern weakness
What’re lower motor neurone
from anterior horn to muscle
What are signs of lower motor neurone diseases due to
Loss of trophic effect on muscle
Signs of lower motor neurone
Wasting
Fasciculation
Lost reflexe
Weakness
What are the two main sensory columns and what do they do
Dorsal columns (touch, vibration , joint position) Spinothalamic tract (pain and temperature)
How do the dorsal column fibres travel
Travel in dorsal root into dorsal column
Synapse in medulla then cross to thalamus
What is significant about blood supply to dorsal column
Blood supply is different from rest of spinal cord. SO in infarcts you can be weak but still have retained joint position sense
What does spinothalamic tract do
Pain and temperature
how do pain and temperature fibres travel
They start in dorsal root and synapse in dorsal column. Then cross spinal cord to the lateral spinothalamic tract then synapse in thalamus then in the cortex.
What does a complete cord lesion cause
Sensory level (complete loss in sense)
What does a half cord lesion cause
Brown squared syndrome
- Loss of light touch and joint position sense on same side (ipsilateral)
- Loss of pain and temperature contralaterally
What does a central cord lesion cause
Loss of pain and too bilaterally over a restricted area (cape over shoulders and going down arms) but no loss in dorsal column
what can middle cerebral artery infarcts cause
contralateral Hemisensory loss
-damage sensory cortex, white matter tracts and internal capsule
What can lesion in thalamic area cause
Pure sensory stroke (contralateral)- no motor loss, only hemisensory loss
What can pure cordial lesions cause
Damage only fine discrimination so only able to feel light touch
How to tell difference between UMN and LMN lesion in the face
UMN spares the forehead so it is not paralysed. Therefore the whole forehead is creased
LMN lesion affects entire face so there can be complete facial paralysis on one side (e.g. Bell’s palsy)
what are the lesion sites which can cause upper motor neurone dysarthria (difficulty swallowing)
1) Cortex
2) Corona radiata
3) internal capsule
4) brainstem corticospinal tract
5) vagus and hypoglossal nuclei
what can bilateral UMN pathway lesions cause
-symptoms
Pseudobulbar palsy
-slow stiff speech and brisk jaw jerk: bilateral strokes
what are lower motor neurone symptoms that cause dysarthria
Slurry speech, poor palate elevation, risky swallow and no brisk jaw jerk
Other causes of dysarthria
- Diffuse cranial neuropathy: Gillian Barre syndrome
- Neuromuscular junction: myasthenia or botulism
- Muscle disorders: forms of dystrophy and inclusion body myositis
- Cerebella disease (scanning/staccato speech)
