RE: Dinosaur Discs

["Stewart, Dwight" <Dwight.Stewart@VLSI.com>]

Hi, All;

   As a person who has had a lot of pets in my lifetime (primarity
quadrapedal) & seen loads of x-rays 
And who has seen quite a few x-rays of horses & cattle too - let me assure
you that they have cartiligenous (sp??? :-)) discs.  So, they aren't only
present in the human spine.  Loss of a disc in a human is USUALLY avoided by
replacing it with a synthetic prosthetic, otherwise; it would effect spinal
length (& one would think, height), placing strain on the whole structure.
I have 3 repaired vertebrae in my neck (5th, 6th, & 7th cervical) & two
between my shoulder blades.  When my arthritis is really acting up, my
height can vary by 2 cms, & yep: it hurts!  :-)  Therapy helps avoid this.
I don't know about dinosaur vertebrae, but discs certainly seem like a good
idea from a structural
Standpoint.   I sure some of the folks at the conference would have good
insight into this.  Logic would also indicate that a reconstruction without
the discs (if they existed) would reduce overall length in an animal with a
horizontal posture.  

Dwight

        -----Original Message-----
        From:   Peter Von Sholly [SMTP:vonrex@gte.net]
        Sent:   Saturday, September 26, 1998 2:07 AM
        To:     dinosaur@usc.edu
        Subject:        Dinosaur Discs

        While looking at the Apatosaurus skeleton at Yale Peabody, I noticed
that
        all the verterbrae seemed butted directly up against each other,
leaving no
        room at all for cartiligenous (sp?) discs in between.  Did dinosaurs
had
        them?  If so, might they not possibly have had, over the length of a
large
        animal, a significant bearing on length of said animal?  Or are
discs
        really only present to the degree we see them in human spines in
erect
        animals that battle gravity and have a lot of flexion?  Just
wondering
        about that.