Using left arm can suck blood from brain

[caesar novus]

Is there some reason 90% of folks are right handed? Even ancient mariners called the right side of boats "starboard" because their dominant right hand steered with a board hung off right side of hull. Wiki suggests the issue may be Darwinian:

Quote

As handedness is a highly heritable trait associated with various medical conditions, and because many of these conditions could have presented a Darwinian fitness challenge in ancestral populations, this indicates left-handedness may have previously been rarer than it currently is, due to natural selection.

Anyway here is something even right handers can consider to reduce negative effects of the left side curse. If you have risk factor of vascular disease (common narrowing with plaque) it normally chokes the left arm artery more than right. The bizarre thing is the onward artery to the brain can be thrown in reverse, sucked down by a busy left arm giving you dizziness and confusion. Maybe don't be like me and try to train the left hand/arm to do half the work 😃 . But before immobilizing your left arm in a sling, remember it once in a while plagues right arms.

 

[guidoLaMoto]

I'd give my right arm to be ambidextrous.-- Yogi Berra

A couple problems with this article--

Almost nobody is truly left handed, ie- right brain dominant/right brain center of language processing-- proved by injection of drugs or MRI studies. ,..For a beast developing skills requiring dexterity, having one side dominant was more efficient.  It just happened to be the right (left brain dominant) by chance- the same reason the L isomer of biochemicals are the biological norm. Once the pattern was established by chance, it was perpetuated by genetics......BTW-- there is also the problem of situs inversus-- all the organs are on the "wrong" side. Also very rare. Also a pattern established way back in evolution and continue because it was effective & efficient.

Subclavian steal syndrome is very uncommon. The left aortic arch/carotid junction is more likely to develop obstructive placque than the right due to hemodynamic considerstions-- just like sand bars are formed at the far side of curves in the river, not the near side. The right side is a "straight shot" up the aorta and into the right carotid....This  makes little difference in perfusion of the brain unless there is also extensive narrowing of arteries to obstruct flow thru the Circle of Willis.....Because this is a problem related to aging, it doesn't appear until well after the reproductive years, thus has virtually no nfluence on genetic selection or evolutionary trends.

Another example of pseudoscientific tripe that never should have made it past the editor or peer review-- a huge problem in science over the past 2-3 decades. Caveat lector.

 

Edited June 26 by guidoLaMoto

[caesar novus]

13 hours ago, guidoLaMoto said:

Another example of pseudoscientific tripe that never should have made it past the editor or peer review

Thanks, it's nice to see you swing your sword against nonsense again; you were getting so genial that I worried that we (and especially I) seemed too hopeless for you to even waste time with debate. Anyway that medical series started as a learning exercise by a young med student. Now as it moves on to obscurities maybe I should unsubscribe. I think it was he that scared me by depicting essential tremor as statistically a stepping stone to dementia.

13 hours ago, guidoLaMoto said:

Subclavian steal syndrome is very uncommon

It looks tricky to diagnose, and with modern vascular clogging lifestyles maybe most cases are undiagnosed. However the condition may be self limiting in that working the affected arm hard makes you want to sit down with head spinning. Folks seem oblivious to lifestyle realities, eg they say take this drug unless you are diagnosed with wonky kidneys. Well, about 110% of the population will eventually have wonky kidneys so better stick to things like tylenol which hurts livers (of alcoholics) rather than kidneys?

13 hours ago, guidoLaMoto said:

For a beast developing skills requiring dexterity, having one side dominant was more efficient

I was the guilty one to digress on "handedness". Not only for dexterity but strength. I hereby end my effort to train my left hand because it leaves both hands equally unexceptional, based experience opening the same jumbo jars of olives for example. I had a fear of losing use of my dexterous hand because practice with my other one was a failure. But recently I lost use of the right for a while, and found that panicked focus could get the left to perform well (if slowly).

Sorry for my fixation, but I once had to measure hundreds of lobsters for a research project and was repelled by their asymmetric claw "handedness". It's logical to differentiate but would you want the mother of your children to have one hand a crusher and the other a ripper?

Edited June 26 by caesar novus