A musical interlude with Joni Mitchell

When Mitchell was 9 she got polio, and while the effects of the disease have not been readily apparent to most of her fans, her music has been creatively shaped by a weakened left arm:

From the beginning, Mitchell played guitar in different tunings to compensate for the fact her left hand had been left weakened by a childhood bout with polio. As a result, her chord shapes, combined with the meandering meters of her more fanciful compositions, tend to resemble jazz more than standard folk or rock.

In a conversation with Joni Mitchell by Jody Denberg, September 9, 1998, Mitchell said:

...the 80s were a rough decade for me and on top of it I was diagnosed as having post-polio syndrome which they said was inevitable for I'm a polio survivor, that forty years after you had the disease, which is a disease of the nervous system, the wires that animate certain muscles are taken out by the disease, and the body in its ingenious way, the filaments of the adjacent muscles send out branches and try to animate that muscle. It's kind of like the EverReady bunny, the muscles all around the muscles that are gone begin to go also because they've been trying to drive this muscle for so long. That's the nature of what was happening so I had it mostly in my back, so you don't see it as much as you would in a withered leg or an arm. But the weight of the guitar became unbearable. Also, acoustic guitar requires that you extend your shoulder out in an abnormal way and coincidentally some of the damage to my back in combination with that position was very painful. So, there was a merchant in Los Angeles who knew of my difficulties and knew that this machine was coming along that would solve my tuning problems and he made on spec a Stratocaster for me out of yellow cedar that was very light and thin as a wafer, so an electric guitar is a more comfortable design for my handicap. Then, a genius lothier built me this two and a half pound guitar which is not only beautiful to look at but it kind of contours to my body. It fits my hip and even kind of cups up like a bra! It's just beautifully designed and then also I abandoned regular medicine and fell into the hands first of a Kahuna and then a Chinese mystic acupuncturist who put down his pins and just points at you. I know this sounds real quacky but they did some mysterious good to the problem and I feel fine.

Direct link to video at YouTube here. It's a live performance of "Both Sides Now" from 1970.