Notice Jaco uses a "big arch" grip technique and does not colapse his hand. Very important to the kind of facility he has on the instrument, helps get around faster on the fretboard. This means keeping the thumb very much centered on the back of the neck.
Just watch where he puts his thumb, you never see it..
I have never heard of the "big arch" grip technique.
Q? Is that the right hand or left hand @surfyogi? :O)
Left Hand!
"get around faster on the fretboard"
Now you've gone and got me all learnamificating @surfyogi lol :O)
..am gonna have to go check that and check what I do. Churz
Exactly, that is also why his thumbs are like a snag :). It is more towards a classical grip, from which I think looks so much more steady. I like his technique very much.
Amazing thumbs that man had!