# multiplesclerosis stockphotos arthritis knee stemcell

In the myelin sheath which protects a neuron's axon is attacked by the immune system due to what is thought to be a virus or defective gene. Without that protective covering nerve signals slow down or stop.

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2018-03-14

Thanks for using our image SS291145 (#Arthritis of the in your for Knee Problems article: https://t.co/DMhsPxBhtN

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2018-01-09