Ape-like or hominid-like? The positional behavior of Oreopithecus bambolii reconsidered.
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Comparative morphological and functional analyses of the skeletal remains of Oreopithecus bambolii, a hominoid from the Miocene Mediterranean island of Tuscany-Sardinia (Italy), provides evidence that bipedal activities made up a significant part of the positional behavior of this primate. The mosaic pattern of its postcranial morphology is to some degree convergent with that of Australopithecus and functionally intermediate between apes and early hominids. Some unique traits could have been selected only under insular conditions where the absence of predators and the limitation of trophic resources play a crucial role in mammalian evolution. (+info)
A polydactylous human foot with 'double-dorsal' toes.
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A human polydactylous left foot with 9 toes, amputated from an 11-mo-old child, was examined by x-ray and magnetic resonance imaging and by gross dissection to identify the digits. The normal sequence of toes from medial to lateral is 1, 2, 3, 4, 5. Examination of the morphology of tendons and muscles suggested the toe sequence was 1, 2, 3/4, ?5, 2, 3/4, 3/4, 5. The 2 toes in the sequence that are underlined were displaced dorsally and were found to have 2 extensor tendons, no flexor tendons and nails that were conical and situated at their tips. These toes resembled those described as 'double-dorsal' and which develop in paws of mice in which a gene normally expressed ventrally is functionally inactivated (Loomis et al. 1996). Specification of toe formation occurs in leg buds early in embryonic development and later there is rotation of the limb so that the anterior (rostral) part comes to lie medially, i.e. the hallux which was anterior (rostral) now is on the inner (medial) side of the foot. A disruption in the patterning of this foot in both anteroposterior (rostral-caudal) and dorsoventral axes during development could be responsible. (+info)
Coregistration imaging of the foot. A new localisation technique.
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We describe a new technique, known as coregistration imaging, which superimposes 99mTc isotope bone scans on to plain radiographs. We used the technique selectively in cases in which the nuclear medicine physician, who reported the isotope scan, had difficulty in localising the anatomical site of the abnormality. In the forefoot, coregistration of isotope scans did not help to localise pathology; the scan alone gave sufficient detail. In 17 patients with pain in the hind- and midfoot, isotope scanning identified eight sites of abnormality in those with normal radiographs. In those with more than one abnormality on plain radiographs the isotope scan eliminated 12 sites of suspicion. Coregistration of the images significantly increased the certainty of localisation of disease (p < 0.001). We recommend the selective use of coregistration scanning as a useful technique for investigating patients with pain in the foot and ankle. (+info)
Anatomical and histological observations of fore- and hind limb toes in adult mice after amputations performed at the age of two weeks.
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Amputation of fore- and hind limb toes in order to numerically identify mice, although an effective and conditionally accepted method, is an ethical issue because of the pain involved and because of the detrimental long term side effects that may be encountered. In transgenic mice sacrificed between the ages of 1 and 1-1/2 y, and in which toe amputations were performed at the age of 2 wk, we observed anatomical (n = 60) and histological (n = 10) changes in bones and soft tissues. In stumps, meduallary cavities of sectioned phalanges became sealed and, therefore, some regrowth must have occurred distal to the amputation plane. However, an important increase in width is seen in the diaphysis of transected bones (P < 0.001) when compared to normal phalanges. Normal epidermis-dermis reorganisation occurred in the stumps. Therefore, when considering solely detrimental long-term side effects related to bone growth and tissue reorganization, toe amputations to numerically identify mice seems an acceptable procedure. (+info)