. Bulletin. Natural history; Natuurlijke historie. cm. ca FIG. 68. Left astragalus and calcancum (reversed) of Deinonychus antirrhopus (YPM 5226) in posterior (A), anterior (B) and distal (C) views. Abbreviations: ca—calcaneum; fif—fibular facet; ta 3—articular surface for tarsal III; ta 4—articular surface for tarsal IV; tif—tibial facets. The internal expansion of the astragalus is considerably larger than the lateral expansion, but the latter is supplemented externally by the calcaneum. With the calcaneum in place, lateral and internal expansions of this joint surface are approximately equa
. Bulletin. Natural history; Natuurlijke historie. cm. ca FIG. 68. Left astragalus and calcancum (reversed) of Deinonychus antirrhopus (YPM 5226) in posterior (A), anterior (B) and distal (C) views. Abbreviations: ca—calcaneum; fif—fibular facet; ta 3—articular surface for tarsal III; ta 4—articular surface for tarsal IV; tif—tibial facets. The internal expansion of the astragalus is considerably larger than the lateral expansion, but the latter is supplemented externally by the calcaneum. With the calcaneum in place, lateral and internal expansions of this joint surface are approximately equal, although not symmetrical. The constricted or narrow-waisted design of this articular surface is best likened to the ginglymoid or saddle-like distal surfaces of phalanges. It permitted a great deal of flexion and extension, but tended to restrict movement to a single plane. The opposing surface, constructed by tarsals III and IV, probably had the obverse form, al- though this cannot clearly be shown with the existing materials. We can con- clude that the tarsus permitted considerable hinge-like movement of the foot, but probably little, if any, transverse adduction or Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Peabody Museum of Natural History. New Haven : The Museum
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Keywords: ., bookcentury1900, bookcollectionbiodiv, booksubjectnaturalhistory
