Kõan-like hand... left hand? Or right hand?

Hello Martijin,
Yes the case is quite abnormal but here is a family with abnormal hands.

THIS IS A CASE OF FAMILY WITH ABNORMAL HANDS:

Inquiry showed that his father was normal; the paternal grandmother had webbed ringers on both hands, but the fingers involved could not be learned; a paternal male cousin had deformities exactly like those shown here in the picture, except for the rudimentary digit growing from the first finger of the left hand in this case; a sister of this cousin was described as an imbecile. You can view here:

http://jhered.oxfordjournals.org/content/7/5/224.1.full.pdf

The case well illustrates how a stock of rather low mentality is often characterized by Physical Defects, which are evidently due to heredity though not identical in each generation.

In answer to the question how far hand deformation can reveal low mentality in Palmistry I would say according to my experience that in such a severe case the subject is having a mental age of three to seven years only. I have found so.

It is the criteria of medical people to research and decide how much physical deformation or defect reveal imbecile.
Parender Sethi
http://www.palmistryforyou.in/

Thank you Martijin for your detailed explation,

I have the opinion that Polydactyly - extra fingers -does not denote mental retardation or low mentality. It is quite common.

But, now, I can take it granted that Syndactyly too -birth defects in which there is partial or total webbing connecting two or more fingers or toes- do not reveal imbecile. Thank you.

Parender Sethi