correlation Flashcards
(15 cards)
UMN lesions
interruption of pathway above anterior horn cell
eg- motor pathways in the cerebral cortex, internal capsule, cerebral peduncles, brain stem or spinal cord
greater weakness of abductors and extensors in the UL, flexors and abductors in the LL > normal function of this pathway is medicate voluntary contraction of antigravity muscles.
no loss of trophic factors hence subtle or no loss of muscle bulk
signs of pyramidal lesion
weakness in all m groups
LL - marked in flexors and abductor muscles.
UL - abductors and extensors.
spasticity - increased tone (clasped knife) > often associated with clonus.
reflexes increased except for superficial reflexes.
extensor plantar response/babinski positive - up going toes.
LMN lesions
weakness more prominent distantly than proximal
flexor and extensor muscles equally involved.
wasting prominent feature.
tone reduced
reflexes reduced.
plantar response normal or absent
fasciculations may be present
level of UMN lesions
1 Leg affected: L1 or above
2 Arm affected: C3 or above
3 Face affected: pons or above
4 Diplopia: midbrain or above
lesions
spasticity > destruction of corticoreticulospinal tract > result in stretch reflex hyperactivity
monoplegia - motor cortex pr partial internal capsule lesion
hemiplegia - lesion affecting projection of pathways from the contralateral motor cortex
paraplegia - result of spinal cord trauma or, less often, a brainstem lesion (e.g. basilar artery thrombosis)
circle of willis fictional importance
1 Anterior cerebral artery - Leg primarily involved
2 Anterior communicating
artery - Connects right and left
internal carotid
3 Penetrating, subcortical branches of middlecerebral artery - Subcortical lacunes,* no cortical deficit
4 Internal carotid, middle
cerebral artery - Dysphasia, or non-dominant hemisphere dysfunction
5 Posterior communicating
artery - May be large with posterior circulation getting significant supply from internal carotid
6 Posterior cerebral
artery - Field cut (supplies occipital
lobe), no hemiplegia
7 Superior cerebellar
artery - Infrequently involved alone
8 Basilar artery - Occlusion results in quadriplegia and death unless there are good anterior collaterals
9 Penetrating branches of the basilar artery to brainstem - Small brainstem infarcts, often classic lacunes
10 Anterior inferior cerebellar artery - Ataxia, nystagmus
11 Posterior inferior cerebellar artery - Lateral medullary syndrome, usually secondary to occlusion of the vertebral artery from which it arises
causes of cerebral embolism
- atrial fibrillation
- carotid atheroma
- aortic arch atheroma
- patent foramen ovale or atrial septal defect (paradoxical embolus from venous system).
Vertebral / basilar (brainstem)
‘Crossed’ motor / sensory (e.g. left face, right arm); bilateral extremity motor / sensory; Horner syndrome; cerebellar signs; lower cranial nerve signs
Anterior cerebral artery
UMN leg > arm; cortical sensory loss leg only; (if corpus callosum affected) urinary incontinence
Posterior cerebral artery
main branch
Infarction of thalamus and occipital cortex: hemianaesthesia (loss of all modalities); homonymous hemianopia (complete); colour blindness
Middle cerebral artery
main branch
Infarction middle third of hemisphere: UMN face, UMN arm > leg; homonymous hemianopia; dysphasia or non-dominant hemisphere signs (depends on side); cortical sensory loss
Perforating artery
Internal capsule infarction: UMN face, UMN arm > leg
cardioembolic stroke
non rheumatic (non valvular) AF
MI
Prosthetic valves
rheumatic heart disease
ischemic cardiomyopathy
small vessel stroke - lacunar infarction - small penetrating artery in brain
atherothrombotic disease
lipohyalinotic thickening
hypertension and age are the main contributors
