Spinal Roots in the Sloth

Abstract

IN the course of an investigation intended to relate the size of the myelinated motor nerve fibres to the speed of the muscles in Choloepus hoffmanni Pet.1, in which the whole musculature is ‘red’ in character, we were struck by the unusual arrangement of the spinal roots. It is generally assumed that the backward obliquity of the spinal roots in adult mammals is due to a differential rate of growth of the spinal cord and of the vertebral column. In man, this obliquity increases from the second cervical root to the filum terminale. In cat, dog and sheep, the obliquity of the D13L2 roots is reduced, but more caudally the roots resume their strong backward direction. In the ox, a similar alteration in the course of the spinal roots leads to a situation where the tenth and eleventh dorsal roots are at right angles to the spinal cord. In the horse, which has 18 dorsal vertebrae, the oblique run of the spinal roots starts from D2 decreases from D11 to D17 and then increases again2.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

References

  1. 1

    Goffart, M., and Gerebtzoff, M. A., J. Physiol. (Paris), 56, 563 (1964).

  2. 2

    Tigges, J., Handbuch der Zoologie, 8, Teil 7, 31 (1964).

  3. 3

    Grassé, P. P., Traité de Zoologie, 17, Fasc. 2, 1195 (1955).

  4. 4

    Hochstetter, F., Morphol. Jahrb., 25, 362 (1897).

Download references

Author information

Rights and permissions

Reprints and Permissions

About this article

Cite this article

GOFFART, M., GEREBTZOFF, M. Spinal Roots in the Sloth. Nature 206, 1062–1063 (1965) doi:10.1038/2061062a0

Download citation

Further reading

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.