This is not a medical question, but let me give some background. Some years ago, I was plagued with daily migraines. My doc sent me to a neurologist. The neurologist found that my coordination was (his word) “mushy” on the left side of my body. He ordered an MRI of my brain, which showed nothing. 
However, lately I’ve noticed that my reactions seem even “mushier” on my left side. It’s fairly subtle: I don’t notice it while walking but can sense it in dance class. This got me to wondering: Why would coordination be different on different sides of the body? Is it all due to which side of the brain is dominant? Does it have anything to do with the number of dendrites or synapses in the parts of the brain that control movement? And is coordination on one side likely to deteriorate more or less rapidly with advancing age than the other side? (I’m in my mid-fifties.)
I should add that I tried to read the Wikki article, but had a hard time focusing. This subject is not my cup of tea.
Thanks.