Thinking about spinal cords

August 28, 2014

I’m scrambling to get everything done before I leave for England and SVPCA this weekend, so no time for a substantive post. Instead, some goodies from old papers I’ve been reading. Explanations will have to come in the comments, if at all.

Streeter (1904: fig. 3). Compare to the next image down, and note that in birds and other reptiles the spinal cord runs the whole length of the vertebral column, in contrast to the situation in mammals.

Streeter (1904: fig. 3). Compare to the next image down, and note that in birds and other reptiles the spinal cord runs the whole length of the vertebral column, in contrast to the situation in mammals.

Nieuwenhuys (1964: fig. 1)

Nieuwenhuys (1964: fig. 1)

Butler and Hodos (1996: fig. 16.27)

Butler and Hodos (1996: fig. 16.27)

For more noodling about nerves, please see:

References

  • Butler, A.B., and Hodos, W. 1996. Comparative Vertebrate Neuroanatomy: Evolution and Adaptation. 514 pp. Wiley–Liss, New York.
  • Nieuwenhuys, R. (1964). Comparative anatomy of the spinal cord. Progress in Brain Research, 11, 1-57.
  • Streeter, G. L. (1904). The structure of the spinal cord of the ostrich. American Journal of Anatomy, 3(1), 1-27.

 

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3 Responses to “Thinking about spinal cords”

  1. Jura Says:

    Hmm, look at that. Turtles are being weird again.

  2. Matt Wedel Says:

    Sorry, I was unclear. Turtles and birds and crocs are normal, in having the default pattern of the spinal cord running the whole length of the vertebral column. In that Nieuwenhuys figure, the turtle is the token vanilla vertebrate, used to contrast the derived shortening of the cord in mammals and anurans. Although I think a lot of the cord-shortening in frogs and toads must surely be driven by the very anterior position of the sacral vertebra and the presence of the urostyle. IOW, I suspect that the long terminal nerves in frogs and toads are probably running posteriorly outside the neural canal, whereas those of mammals run inside the neural canal, and form the cauda equina.

  3. David Marjanović Says:

    Huh. I had no idea of this mammalian and anuran weirdness.


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