[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

RE: Anatomical directions for decribing coracoids



evelyn sobielski writes:
 > > > Asking as a dedicated retroactivist; is it useful to go w/
 > > > priority?
 > > 
 > > Not if it is positively misleading compared to the orientation of
 > > the coracoid (that being the real source of the confusion).
 > 
 > The problem, as far as I can see it, is that usually a
 > directional term like "proximal/distal" is to be
 > preferred to a posture-relative one like "anterior",
 > "ventral" etc. Problem with the coracoid: it's by no
 > means certain. The end closest to the manus (which
 > would usually be "distal") is also the one closest to
 > the spinal column (which usually would be "proximal").
 > Hence, I guess, the confusion.

Correct -- in part.  The other part of the problem with the coracoid
is simply that there is so much disagreement over how it should was
oriented in life.  The scapulocoracoid would have been oriented such
that the scapula blade pointed somewhere between posteriorly and
anteriorly, but whether it was at 45 degrees or more or less is much
debated.  Add in the the coracoid may have "wrapped round" the front
of the torso somewhat -- see for example the old Humboldt
Brachiosaurus brancai mount, in which the coracoids nearly meet on the
midline -- and you can see why descriptions of the edge furthers from
the scapula have included inferior or ventral (assuming a vertical
scapula), anterior (assuming a horizontal scapula), anteroventral
(assuming 45 degrees), medial (assuming 90-degree wrap-around,
anteromedial (assuming 45 degree wraparound), anteroventromedial
... well, you get the picture.

 > One might be tempted to break ground and simply start
 > using "sternal end" and "scapular end" (or maybe
 > "sternad" and "scapulad")...

That is not acually such a bad idea, except that -- as with proximal
and distal -- that only gives you two of the four (or six) directions
you need.  If I went with sternal and scapular, then what would I call
the edge of the coracoid that, were the scapula horizonal, would be
the anterior edge?

So, no, I think that proximal/distal and sternal/scapular are misfires
in this context, and that it's better just to assume a particular
orientation and then use the standard directions.  (And let's not even
get into the use of cranial/caudal for anterior/posterior!  If I read
one more papar about cranial caudal elements, or caudal cranial
elements, I'm going to have to go get that Quad Damage and do some
harm.)

 _/|_    ___________________________________________________________________
/o ) \/  Mike Taylor    <mike@indexdata.com>    http://www.miketaylor.org.uk
)_v__/\  "There is a huge switching cost to using a different operating
         system.  It is this switching cost that has given customers
         the patience to stick with Windows through all our mistakes,
         our buggy drivers, our high TCO, our lack of a sexy version" --
         Microsoft's C++ Manager Aaron Contorer, in a memo to Bill Gates.