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The relationship of trabecular architecture to inferred loading patterns in the third metacarpals of the extinct equids Merychippus and Mesohippus

Published online by Cambridge University Press:  08 February 2016

J. J. Thomason*
Affiliation:
Department of Vertebrate Palaeontology, Royal Ontario Museum, 100 Queens Park, Toronto, Ontario M5S 2C6, Canada Department of Zoology, University of Toronto, Toronto, Ontario, M5S 1A1, Canada

Abstract

The internal structures of the third metacarpals of Merychippus and Mesohippus are assessed from thin sections and from radiographs, and systems of trabeculae differing in orientation and density are described. The principal forces transmitted to the articular surfaces of these bones are reconstructed and are used to estimate the pressure of contact on each surface. The major correlations made between the structure and the function of the third metacarpal of Equus (Thomason, 1985a) are also observed in this bone in Merychippus and Mesohippus. More important, the differences in trabecular structure among the recent and fossil bones may be interpreted in terms of the differences in inferred function. Thus the functional interpretation of the internal structure of fossil bones may reasonably be attempted.

Type
Research Article
Copyright
Copyright © The Paleontological Society 

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References

Literature Cited

Bartel, D. L., Schryver, H. F., Lowe, J. E., and Parker, R. A. 1978. Locomotion in the horse: a procedure for computing the internal forces in the digit. Am. J. Vet. Res. 39:17211728.Google Scholar
Biewener, A. A., Thomason, J., Goodship, A. E., and Lanyon, L. E. 1983a. Bone stress in the horse forelimb during locomotion at two different gaits: a comparison of two experimental methods. J. Biomech. 16:565576.CrossRefGoogle ScholarPubMed
Biewener, A. A., Thomason, J., and Lanyon, L. E. 1983b. Mechanics of locomotion and jumping in the horse forelimb: in vivo stress developed in the radius and metacarpus. J. Zool. London 201:6782.CrossRefGoogle Scholar
Camp, C. L. and Smith, N. 1942. Phylogeny and functions of the digital ligaments of the horse. Mem. Univ. Calif., Berkeley 13:173.Google Scholar
Cook, S. F., Brooks, S. T., and Ezra-Cohn, H. E. 1962. Histological studies on fossil bone. J. Paleontol. 36:483494.Google Scholar
Hayes, W. C., Swenson, L. W., and Schurman, D. J. 1978. Axisymmetric finite element analysis of the lateral tibial plateau. J. Biomech. 11:2133.CrossRefGoogle ScholarPubMed
Hayes, W. C., Snyder, B. M., Levine, B. M., and Ramaswamy, S. 1982. Stress-morphology relationships in trabecular bone of the patella. Pp. 223267. In: Finite Elements in Biomechanics. Gallagher, R. H. et al., eds. Wiley; New York.Google Scholar
Jayes, A. S. and Alexander, R. McN. 1978. Mechanics of locomotion of dogs (Canis familiaris) and sheep (Ovis aries). J. Zool. London 185:289308.CrossRefGoogle ScholarPubMed
Meyer, G. H. 1867. Die Architektur der Spongiosa. Arch. Anat. Physiol. Wiss. Med. 34:615628.Google Scholar
Shotwell, J. A. 1961. Late Tertiary biogeography of horses in the northern Great Basin. J. Paleontol. 35:203217.Google Scholar
Sondaar, P. Y. 1968. The osteology of the manus of fossil and Recent Equidae. Verh. K. Ned. Akad. Wet. 25:176.Google Scholar
Stirton, R. A. 1940. The phylogeny of the North American Equidae. Univ. Calif. Publ., Bull. Geol. Sci. 25:165198.Google Scholar
Thomason, J. J. 1985a. Estimation of the locomotory forces and stresses acting on the limb bones of Recent and extinct equids. Paleobiology 11:287298.CrossRefGoogle Scholar
Thomason, J. J. 1985b. The relationship of structure to mechanical function in the third metacarpal of the horse Equus caballus. Can. J. Zool. 63:14201428.CrossRefGoogle Scholar
Thomason, J. J. In prep. The functional morphology of the manus in the tridactyl equids Merychippus and Mesohippus: paleontological inferences from neontological models. Submitted.Google Scholar
Treharne, R. W. 1981. Review of Wolff's Law and its proposed means of operation. Orthop. Rev. 10:3547.Google Scholar
Wolff, J. 1870. Über die innere Architektur der Knochen und ihre Bedeutung für die Frage vom Knochenwachstum. Virchows Arch. Pathol. Anat. 50:389450.CrossRefGoogle Scholar