In article <D29rwA.JLM at murdoch.acc.Virginia.EDU>,
mlm2s at galen.med.Virginia.EDU (Mallory Leslie McClure) wrote:
> Today I examined a 24 year old patient who had experienced a
> stroke at birth. The stroke had damaged the left side of her
> brain such that the right body was affected. There was marked
> hypoplasia of the right extremities, particularly the right arm
> and hand. What is the mechanism for this? Is it just the
> decrease in trophic signals to the muscles resulting from
> neuronal destruction? Besides the hypoplasia, the patient had
> few other deficits that could be picked up with the naked eye.
> I was amazed!! At this rate, I may end up wanting to be a
> neurologist--admittedly, I have a lot more to learn but I find
> it very interesting!!
You are really interested in strokes which is a good way to learn
neuroanatomy but to tell you the honest truth their really isn't much
variation. Yes every stroke is different for every different person but
you can probably categorize strokes into perhaps 10 categories (if that many).
First off I'm sure you know that the tracts cross over in the medulla so
the right side of the brain controls the left and visa versa.
To find the answer to your question look at the hominuculous of the brain.
It can be found in Netter and it shows the areas of the brain which control
motor imput to the extremities.
Strokes can make the extremities flaccid or hypertonic or somewhere in
between. The motor areas of the brain control the muscle spindles and
gogi tendon organs. These are responsible for the tonic changes you see
in muscles. Read up on muscle spindles and golgi tendon organs for details.
Cerebral Palsy is a condition that affects children like strokes do adults.
Many of them are spastic and there is an operation called a dorsal rhizotomy
which changes the bias of the muscle spindles and reduces the tone. I believe
the rootlets in the lower spinal cord are cut to produce this effect. (Its
been a while since I last read up on this procedure, maybe you might want
to explore this yourself. You do have access to medline?
Anyway neurology is indeed any exciting field. Its great because there is
a direct correlation of injury to the neuroanatomy. So everytime you get
a case it requires you to know your neruoanatomy which strengthens or adds
to your knowledge. There are myraids of neurological injuries which are
more exciting than strokes and aren't as black and white. Enjoy!!
Cardiology is also fascinating. Give that whack!!!!
Hope this helps
Alan
