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Metacarpal neck fracture is one of the most common types of hand fractures; the literature suggests that applying a bone plate on the dorsal side provides higher fixation strength than that provided by other fixation methods. Howe...
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Metacarpal neck fracture is one of the most common types of hand fractures; the literature suggests that applying a bone plate on the dorsal side provides higher fixation strength than that provided by other fixation methods. However, bone plate fixation on the dorsal side may result in postoperative tendon adhesion. So far, no studies have investigated the fixation of metacarpal neck fractures on the volar side by using a bone plate. The objective of this study was to investigate the differences in the fixation results between bone plate fixation on the dorsal side and bone plate fixation on the volar side of the metacarpal in the case of a metacarpal neck fracture. A saw blade was used to create a transverse metacarpal neck fracture on 14 artificial metacarpal bone specimens. The specimens were divided into 2 groups depending on the fixation method: a volar locking plate (VLP) group and a dorsal locking plate (DLP) group. All specimens were subjected to a cantilever bending test on a material testing system, and a force–displacement curve was used to measure the yield force and stiffness, which served as an indicator of the fixation ability of the 2 fracture fixation methods. For the experimental results, the Mann–Whitney U test was used to compare the fixation abilities of the 2 fixation methods. In terms of yield force, the DLP group (266.9 ± 68.3 N) scored significantly higher than the VLP group (32.6 ± 2.7 N) ( P < .05); expressed in terms of median, the DLP group scored 8.2 times higher than the VLP group. Similarly, in terms of stiffness, the DLP group (69.0 ± 13.4 N/mm, median ± interquartile range) scored significantly higher than the VLP group (12.9 ± 1.4 N/mm) ( P < .05); expressed in terms of median, the DLP group scored 5.3 times higher than the VLP group. The fixation strength of volar bone plates is only about one-third of that of dorsal bone plates.
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Neck injury remains a major issue in road safety. Current side impact dummies and side impact crashworthiness assessments do not assess the risk of neck injury. These assessments are limited by biofidelity and knowledge regarding ...
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Neck injury remains a major issue in road safety. Current side impact dummies and side impact crashworthiness assessments do not assess the risk of neck injury. These assessments are limited by biofidelity and knowledge regarding neck injury criteria and tolerance levels in side impacts. Side impact tests with PMHS were performed at the Heidelberg University in the 1980s and 1990s to improve primarily the understanding of trunk dynamics, injury mechanisms and criteria. In order to contribute to the definition of human tolerances at neck level, this study presents an analysis of the head/neck biomechanical parameters that were measured in these tests and their relationship to neck injury severity.Data from 15 impact tests were analysed. Head accelerations, and neck forces and moments were calculated from 9-accelerometer array head data, X-rays and anthropometric data. Statistically significant relationships were observed between resultant head acceleration and neck force and neck injury severity. The average resultant head acceleration for AIS 2 neck injuries was 112g, while resultant neck force was 4925 N and moment 241 Nm. The data compared well to other test data on cadavers and volunteers. It is hoped that the paper will assist in the understanding of neck injuries and the development of tolerance criteria.
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Numerical analyses of the head and neck responses daring side impact are presented in this paper. A mathematical human model for side impact simulation was developed based on the previous studies of other researchers. The effects ...
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Numerical analyses of the head and neck responses daring side impact are presented in this paper. A mathematical human model for side impact simulation was developed based on the previous studies of other researchers. The effects of muscular activities during severe side impact were analyzed using this model. This study shows that the effect of muscular activities is significant especially if the occupant is prepared to resist the impact. This result suggests that the modeling of muscles is important for the simulation of real accident situations.
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Bilateral chylothorax is a rare complication of neck dissection, but it is potentially serious and sometimes life threatening. Because of the rarity of chylothorax, surgeons are unfamiliar with its early signs, which allow a promp...
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Bilateral chylothorax is a rare complication of neck dissection, but it is potentially serious and sometimes life threatening. Because of the rarity of chylothorax, surgeons are unfamiliar with its early signs, which allow a prompt diagnosis and effective management. Most cases reported in the literature were associated with a concurrent external chyle leakage, which occurred either during or after surgery. We report two cases of bilateral chylothoraces without concurrent external chyle leakage, which occurred after left-sided neck dissections for thyroid cancer. We treated both patients successfully with conservative management.
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Three skulls of Ummulisani rutgersensis are described here as an addendum to the descriptions and analyses presented in Gaffney et al. (2006a). The present paper is essentially a replacement for the Ummulisani cranial morphology t...
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Three skulls of Ummulisani rutgersensis are described here as an addendum to the descriptions and analyses presented in Gaffney et al. (2006a). The present paper is essentially a replacement for the Ummulisani cranial morphology text in that paper (Gaffney et al. 2006a: 447-457). The original description was based primarily on one skull, AMNH 30563, the type of Ummulisani rutgersensis. Because two previously undescribed skulls, AMNH 30569 and AMNH 30562, are more complete, they add significantly to our understanding of this taxon. However, it does not alter the results of the phylogenetic analysis by Gaffney et al. (2006a), in that Ummulisani rutgersensis remains the sister taxon to Phosphatochelys tedfordi.
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The early Oligocene "Podocnemis" fajumensis and the early Miocene "Podocnemis" aegyptiaca are two podocnemidid turtles from northern Egypt, defined more than a century ago. Their identification as representatives of the South Amer...
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The early Oligocene "Podocnemis" fajumensis and the early Miocene "Podocnemis" aegyptiaca are two podocnemidid turtles from northern Egypt, defined more than a century ago. Their identification as representatives of the South American genus Podocnemis cannot currently be supported. Relatively limited information on both species was available. In fact, no photograph on the shell of either of them has been published so far, and the type material of both is currently lost. Shell remains of almost 15 specimens of "Podocnemis" fajumensis are analyzed here, including a complete carapace and two complete plastra. A neotype is designated here for the species. An artificial mold of the holotype of "Podocnemis" aegyptiaca is identified, corresponding to its holoplastotype. Both "Podocnemis" fajumensis and "Podocnemis" aegyptiaca are confirmed as valid species, attributable to Erymnochelyini, a Glade currently exclusively represented by the Malagasy Erymnochelys madagascariensis. A new diagnosis is proposed for each of these extinct species, including both autapomorphies and a unique combination of characters. They are attributed to two new genera, corresponding to the oldest defined for the African record of Erymnochelyini. Thus, the new combinations Shetwemys fajumensis (http://zoobank.org/NomenclaturalActs/B4805343- 8533-4DA7-808B- BB972D4471. CB, um: lsi d: zoobank.org :act: 84805343-8533-41)A7- 808 B -B B9721)4471. C B) and Apeshemys ae- gyptiaca (http://zoobank.org/NomenclaturalActs/43DD73CF-AAED-47A0-9FFB-EB6CFB80D389, um: lsid: zoobank.org :act :43DD73CF-AAED-47A0-9FFB-EB6CFB80D389) are proposed.
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Neck injury remains a concern in ejection seat-equipped military aircraft with the growing use of helmet-mounted displays (HMDs) worn for entire mission durations, as well as in the automotive and civilian aircraft domains. Existi...
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Neck injury remains a concern in ejection seat-equipped military aircraft with the growing use of helmet-mounted displays (HMDs) worn for entire mission durations, as well as in the automotive and civilian aircraft domains. Existing U.S. Department of Defense criteria are overly complex and not clearly tied to injury risk and thus require improvement. Purpose: This study developed a lateral (Gy) impact, upper neck injury criterion for use in the design and test of U.S. Department of Defense escape systems and HMDs. Methods: A multi-axial lateral impact risk function, referred to as MANIC(Gy), was constructed using the survival analysis of a data set that combined human subject (N = 56) and postmortem human (N = 9) data. The human subject data were analyzed to assess criterion sensitivity to anthropometric factors. Additionally, a risk function was applied to quantify the risk associated with changes in HMD mass and acceleration input. Results: A lateral impact (Gy), upper neck injury criterion is proposed, which yields a 5% risk of Abbreviated Injury Scale (AIS) 2 or greater injury at a criterion value of 0.48 (95% confidence intervals of 0.28 and 0.67, respectively). At an injury level of AIS 3 or greater, a risk function was generated that yields a 5% risk at a criterion value of 0.53 (95% confidence intervals of 0.24 and 0.82, respectively). Conclusions: This initial multi-axial risk function could be applied to quantify the risk of neck injury posed by lateral acceleration. Criterion values were correlated with body mass and related anthropometric factors, indicating that the critical values incorporated in this study may require improvement. This same criterion may be useful for analyzing side impact safety in other vehicle systems (e.g., automotive and civilian fixed wing or rotary wing aircraft).
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Background: The potential for neck injury in high accelerative environments must be understood to ensure occupant safety during crashes or ejections, such as when operating aircraft or other high-performance vehicles. A human-deri...
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Background: The potential for neck injury in high accelerative environments must be understood to ensure occupant safety during crashes or ejections, such as when operating aircraft or other high-performance vehicles. A human-derived, injury risk criteria has been proposed earlier, which considers five forces or moments to calculate the risk of upper-neck injury in the context of human lateral impacts (Gy). Purpose: Develop a method to transform human Gy upper-neck injury responses to an ATD-equivalent response. The equivalent response is used to identify human-equivalent risk during testing involving ATDs. Methods: Multiple regression was used to evaluate ATD and human upper-neck injury criterion based on a multi-axial neck injury criteria (MANIC(Gy)). The difference in modeled responses at instantaneous peak acceleration defined the transfer function for converting human responses to ATD-equivalent responses. Survival analysis was employed to evaluate human and ATD neck injury risks. Results: Use of the six factor (SF) MANIC(Gy) was found necessary when evaluating Hybrid III ATD neck responses. Human MANIC(Gy) was influenced by Peak G and helmet wear. ATD SF-MANIC(Gy) was influenced by these same factors, as well as peak G~3 and a significant intercept. The ATD-equivalent AIS2+ risk curve is steeper and is shifted to the left of the MANIC scale when compared to the human risk curve counterpart. Conclusions: This research bridges the gap between human response functions and the more practical use of ATDs for system evaluation. The method presented here can be applied to generate similar transforms for frontal and vertical force profiles as well as alternate ATD necks.
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Myuchelys, a new genus, is erected for a well supported clade of Australasian freshwater turtles; its establishment resolves an unacceptable paraphyly in relationships among species of the genus Elseya. Molecular and morphological...
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Myuchelys, a new genus, is erected for a well supported clade of Australasian freshwater turtles; its establishment resolves an unacceptable paraphyly in relationships among species of the genus Elseya. Molecular and morphological evidence indicates that the closest relationship of the new genus is with Emydura, not the redefined Elseya. The genus Elseya has had a long and confused history. It was erected by Gray (1867) for the species Chelymys [now Elseya] dentata Gray, 1863 and Elseya latisternum Gray 1867. Elseya dentata was later designated as the type species (Lindholm, 1929). The genus was diagnosed by the presence of a horny shield on the dorsal surface of the head; flat polygonal plates on the temples, cheeks and throat; prominent tubercleson the dorsal surface of the neck; a pair of tubercles on the chin; and the usual absence of a cervical scute (Gray, 1867; Gray, 1872). Boulenger (1889) redefined the genus, placing significance on the alveolar ridge (a longitudinal ridge on the triturating surface of the maxillary sheath and underlying bone) as a character, then known to be present only in Elseya dentata. Elseya latisternum and Elseya novaeguineae (Meyer, 1874) lack the alveolar ridge, and so Boulenger placed them in the genus Emydura.Later, Goode (1967) disagreed with the importance placed on the alveolar ridge, noting that well-established cryptodiran genera displayed considerable variation in this character, and returned E. latisternum and E. novaeguineae to the genus Elseya.
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Myuchelys, a new genus, is erected for a well supported clade of Australasian freshwater turtles; its establishment resolves an unacceptable paraphyly in relationships among species of the genus Elseya. Molecular and morphological...
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Myuchelys, a new genus, is erected for a well supported clade of Australasian freshwater turtles; its establishment resolves an unacceptable paraphyly in relationships among species of the genus Elseya. Molecular and morphological evidence indicates that the closest relationship of the new genus is with Emydura, not the redefined Elseya. The genus Elseya has had a long and confused history. It was erected by Gray (1867) for the species Chelymys [now Elseya] dentata Gray, 1863 and Elseya latisternum Gray 1867. Elseya dentata was later designated as the type species (Lindholm, 1929). The genus was diagnosed by the presence of a horny shield on the dorsal surface of the head; flat polygonal plates on the temples, cheeks and throat; prominent tubercleson the dorsal surface of the neck; a pair of tubercles on the chin; and the usual absence of a cervical scute (Gray, 1867; Gray, 1872). Boulenger (1889) redefined the genus, placing significance on the alveolar ridge (a longitudinal ridge on the triturating surface of the maxillary sheath and underlying bone) as a character, then known to be present only in Elseya dentata. Elseya latisternum and Elseya novaeguineae (Meyer, 1874) lack the alveolar ridge, and so Boulenger placed them in the genus Emydura.Later, Goode (1967) disagreed with the importance placed on the alveolar ridge, noting that well-established cryptodiran genera displayed considerable variation in this character, and returned E. latisternum and E. novaeguineae to the genus Elseya.
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