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RE: semi-lunate carpal questions




Thankyou very much for your reply Dr Holtz. It was very interesting (though I shall have to wait till I next have a chicken dinner for complete elucidation.)


Moving only at your wrists, move your hands up and down. This is the motion
permitted by the semilunate carpal: a lot more degrees of motion than we can
get with our hands, though.

190 degrees, according to K. Padian. But less degrees of freedom overall.


Moving only at your wrists, move your hands inward (so your palms face
towards you and your arms make something approximating an right angle like a
wrist). If you were a maniraptoran, you would have popped your wrists WAY
out of joint. This motion is not possible for a maniraptoran.

Is this because the semi-lunate carpal "caps" metacarpals I and II and therefore limits the dorso-ventral movement of the hand ?



Like Rob Gay, I am also interested in why theropods had such limited pronation-supination of the forearm. Were the radius+ulna positioned so there was little rotation available ?


Chris

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