forelimb posture

["Pat Grant (Library: Serials Catalog" <PATG@vax2.concordia.ca>]

Naturally I left the printout at the office, so can't quote the
relevant passage, but Allan Edels (sorry if I misspelled that) quoted
an article by Dodson and Farlow, 1991 (?) in which it was stated that
the humerus of ceratopsians has to "sprawl" about 30 degrees in order
to prevent the proximal end of the humerus from bashing into a rib.

This theory is based on a false premise.  The humerus does not
articulate lateral to any rib; the glenoid is completely free of the
ribcage, and anterior to it, or as Ken Carpenter put it in a post to 
the DML, Jan. 19, 1996:

"As all naturally articulated dinosaur skeletons show, the first
dorsal rib bisects the scapula about midway along its length. If the
Torosaurus were mounted so that the ribcage was narrow at the front
and wide[r] posteriorly (as in all living vertebrates), and placing
the scapula so that the first rib bissected it at the mid point, the
coracoids would be much, much closer (almost touching) and the elbows
would be brought in."

So, no opportunity for the proximal humerus to bump any rib even if it
wanted to, and no need to sprawl out the leg to avoid this nonexistent
problem.  (Carpenter also points out that this misrestoration can be
caused by mounting the ribs too vertically, which distorts the shape of
the chest.)  

Now, *elbows* bashing into the ribs may be a different matter...

Pat Grant
patg@vax2.concordia.ca