Re: "Heel to Toe"

["Matthew Bonnan" <mbonnan@hotmail.com>]

Hi Natasha:

Many people on this have already said a great deal to help you, so I'm just 
adding a few more notes.

As many people have already stated, all dinosaurs walked on their toes.  If 
you watch a bird walk, that gives you an idea of how the meat-eating 
varieties' foot would have looked.  The way a bird or a meat-eating dinosaur 
walks would be equivalent to you standing upright on your toes, your heel 
off the ground.  Dinosaurs do have a "heel," but for the most part it is 
held clear of the ground.  If you look at a bird leg, above the toes you 
will notice that there is a hinge joint that faces backwards.  This is the 
"heel" of a bird.

Except in rare circumstances, the heel never touched the ground.  In bigger, 
heavier dinosaurs, the foot was angled and supported by a flesh pad, but the 
heel itself was foreshortened and lay next to the ankle.  Even sauropods, 
the big, long-necked herbivores, essentially walked on their toes.

We know this is so because of footprints and from articulating and 
assembling the foot skeletons of dinosaurs together.

The name of the "heel" bone in a human is called the calcaneus.  In 
dinosaurs and birds it is called the calcaneum.  In humans, the calcaneus 
lies below the ankle (a bone called the talus in humans, astragalus in 
everything else) and points backwards.  This is the case in mammals.  In 
birds, reptiles, and dinosaurs, there is a different situation.  The 
calcaneum lies next to the astragalus, and both form a cylinder-like joint 
that the foot bones articulate with (metatarsals).  The toes (phalanges) lie 
below the metatarsals, and are usually what touched the ground, occasionally 
with the metatarsals.

So, humans walk heel-to-toe because our heel lies below our ankle.  This was 
not possible in dinosaurs, because their heel lies next to their ankle and 
both together form the ankle joint.

Hope this helps on top of what has already been said,

Matt Bonnan
Dept Biological Sciences
Northern Illinois University
DeKalb, IL 60115 USA


> From: Natasha Ramsey <dinobabe@earthlink.net>
> Reply-To: dinobabe@earthlink.net
> To: "dinosaur@usc.edu" <dinosaur@usc.edu>
> Subject: "Heel to Toe"
> Date: Mon, 31 Jan 2000 19:20:41 -0600
>
> A question came up in my Invertebrate Paleo class today that we did not
> know the answer to.  I was wondering if anyone out there knew.  The
> question is "Did dinosaurs walk from heel to toe like humans do?"
> Thank you in advance.
>
> --
> Natasha Ramsey
>
> Student of Geological Sciences
> University of Memphis
>
> Event Coordinator
> West Tennessee F-Body Association

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