DrVirgo
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What are they symptoms of ACA occlusion?
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| msyamp
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big one boss better read it in book
shortly you can have legs below knee weakness. urinary and bowel problems. and a lot more variety of syndromes depending on he area affeected. it usually has sudden onset
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| drk1980
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Points summarised from Kaplan...
ACA is one of the terminal branches(smaller) of Internal Carotid Artery. The other's MCA.
Location---> consequent lesion:
1)medial surface and 1" superiorly on lateral aspect of frontal & parietal lobe : motor & sensory for pelvis+lowerlimb---> urinary incontinence+spastic paresis & anesthesia of C/L lowerlimb.
2)anterior 4/5ths of corpus callosum---> transcortical apraxia
3)anterior limb of internal capsule : papez circuit from thalamus to cingulum, part of the limbic system
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| DrVirgo
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Drk, Thanks for your help.
1. I agree. note: urinary incontinence only if bilateral lesion.
2. Can you please explain: 'Transcortical Apraxia' Kaplan Anat says: transcortical apraxia of the left limbs. Is this due to lesion of ACA on the L or R?)
3. Agree, but lesion of it has what affect?
Also if you look in Kaplan Patho
Under ACA it says:
-Weakness or sensory loss in contra leg (same as anat)
-Transient expressive aphasia (?)
-Abulia (?)
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| drk1980
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About 1. good! But also note tht its USUALLY in B/L cases.
2. Transcortical apraxia is seen in lesions of the anterior 4/5th of the corpus callosum. A command to move the right hand is perceived by the receiving centre(Wernicke's), but is not passed to the appropriate hand moving centre, ie. the primary motor cortex on the right. BCOZ the fibres pass thru this corpus callosum. but he can move the right hand whnever he wants to...jsut not on command. You wont hv transcortical apraxia on the left coz the wernickes is on the left lobe. So the fibres dont need to pass thru corpus callosum.
3. Hvnt come across this one...but u know i think its more imp for USMLE to know effects of lesion in the posterior limb. so do tht well.
Kaplan patho...abulia is a general loss of all impulsivity...seen in frontal lobe lesions. Not sure if that is the cause for the 'transient' expressive aphasia. My advise, stick to kaplan neuroanat for neuroanat Qs...
hope sm1 can add more info.
Oops: noted my mistake just now! Geroo(refer post below) is right to point it out. Transcortical apraxia is related to the left limbs....as the right primary motor cortex fibres wud decussate in the pyramid!
Edited by drk1980 on 02/25/06 - 12:05 PM. Reason: correction
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| sturge_weber
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well transcortical apraxia
drk has explained well... some more. the only way u can differntiate, is tell the patient to move the right hnd , he cant but u will see he will move his right hand if he has say a fly sitting on him ie without a command
this is because when u give command to the person, it will go first to the wernickes area, which is in the left hemisphere and then will go to the right motor cortex for execution of action, for this to happen it has to pass thro the corpus callosum. the aca supplies this, and when aca is gone, the ant 4/5 of the corpus callosum is not working and hence the information cant go to the right hemisphere and he will not execute the action
but now u tell him to move his left hand, now the info goes to the wernickes area and then to the left cortex for execution of the plan, now in this case it does not have to pass thro the corpus callosum
hence we conclude that transcortical apraxia, is inability to move the right hand on command
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| msyamp
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sturge way to go. drk you too
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| Geroo
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good explanation sturge and drk,but in transcortical apraxia the patient can't excute command to move his left limb not right.
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