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Old 11-07-2008, 09:52 AM #20 (permalink)
Spacemonkehh
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Spacemonkehh
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Quote:
Originally Posted by Hyppo View Post
Just thought I'd say this in case this is something you worry about. Upper and lower motor neurons have nothing to do with upper and lower body. LMN signs are weakness, twitches and muscle wasting. UMN signs are brisk reflexes, slowness, and bad coordination. You can have LMN signs in the upper body as well as UMN signs in the lims. Feel free to correct me if I'm wrong.
Upper motor = the nerves connecting the brain with the spinalcord, at a specific point the lower motor takes over.
Lower motor = the motor nerves connecting the brain and spinal cord to the limbs and muscle fibers.

Brisk reflexes are so taken out of context; You can have brisk reflexes.. but if this is found in all limbs and regions then it is still considered normal. Abnormal reflexes are found when you have clonus after the examinor slams with a hammer on the tendon and you keep on shaking. A fast or brisk reflex with no after shocks is still considered normal if found on both sides. Absent reflexes ( no reaction ) can be a sign of lower motor neuron damage. While the babinski's sign and hoffman's sign are both indicators of upper motor neuron damage.

So;
A brisk reflex in both legs is considered normal
A brisk reflex in one leg, but no reflexin the other is considered abnormal
A reflex is considered abnormal when clonus are present.