Re: Another anatomy question

["Jaime A. Headden" <qilongia@yahoo.com>]

I wrote:

<<For clarification's sake to something Ray Stanford wrote, the neural arch is 
every part of the
vertebra that is not the centra, and includes the neural pedicels and all 
apophyses (neurapophyis
[neural spine], diapophyses, parapophyses, and zygapophyses, and in birds, the 
hypoapophysis).">>

Ray Stanford (dinotracker@earthlink.net) wrote:

<I was using the definition of neural arch given in Jeff Poling's on-line 
Anatomical Dictionary,
which gave this definition: "...the opening in a vertebra through which the 
spinal cord passes".

Just below that, Jeff defines neural spine as, "...the large 'spike' of bone 
that rises above the
top of a vertebra to which the muscles and tendons...attach".>

  The neural arch is every part of the vertebra that is not the centrum. In 
this sense, it is an
arch. The space between the body of the arch and the centrum, and between both 
lateral [neural]
pedicels is the neural canal.

<That it, why call a group of bony extensions an arch???>

  All the processes that jut from the vertebra save two are part of the arch 
itself, but the term
arch can also be limited to the body of the arch devoid of the processes, 
called apophyses. A more
detailed description of these is below.

David Marjanovic (david.marjanovic@gmx.at) wrote:

<BTW, I think the diapophyses are the transverse processes.>

  They are, to a degree. Definitions are as follows, pretty general for the 
most part:

  neurapophysis (neural spine): projects dorsally from the body of the arch, 
medially (or
    centrally) situated from the lateral margins.
  diapophysis: also generally called a transverse process, this is the 
projection of bone that
    bears the facet for the tuberculum of the rib, which may not be confulent 
with the body of the
    the transverse process. Both can be called "transverse" process. These are 
also termed
    mammilary processes in mammalian biology, for the lumbar or non-rib-bearing 
dorsal vertebrae.
  parapophysis: the pedunculate process that bears the facet for the capitulum 
of the rib, either
    on the centrum, the margin between centrum and arch, or on the arch alone.
  zygapophysis: process that holds consecutive vertebrae in sequence, 
effectively "yoking" them
    together [pun intended]. Prezygapophyses have facets that face dorsally and 
medially
    (inwardly) and the postzygapophyses have facets that face laterally and 
ventrally. The facets
    also face toward the front or back (respectively).

  There are two other processes tat are worth mentioning: the hyposphene is a 
posterior projection
    between the postzygapophyses that articulations with the hypantra [pl.; the 
singular
    is 'hypantrum'] which are between the prezygapophyses and may only resemble 
to small facets on
    the prezygapophyseal shafts. In some forms, these are distinct processes.


=====
Jaime A. Headden

  Aaaaaaaaaaaaaaaaaaaahhhhhhhhhhhhhhhhhhr-gen-ti-na
  Where the Wind Comes Sweeping Down the Pampas!!!!

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