Planteamos en la presente investigación diversas cuestiones sobre la información geográfica proporcionada por Humboldt en su viaje a Nueva España, incidiendo en los datos relativos al ámbito de las ...Provincias Internas y sus desarrollos cartográficos, con las correcciones oportunas en mediciones astronómicas y la situación de algunos lugares claves; los detalles suplementarios de hidrografía y orografía permitieron al sabio prusiano perfilar sus propios mapas sobre el Septentrión mexicano, en una tarea encomiable, pues debido a la relativa brevedad de su estancia en el virreinato la labor cartográfica se basó (al contrario que en Venezuela) en la lectura y corrección de referencias indirectas.
Category:
Hindfoot; Midfoot/Forefoot; Other
Introduction/Purpose:
Progressive collapsing foot deformity (PCFD) is a complex three-dimensional (3D) deformity characterized by peritalar subluxation ...(PTS) of the hindfoot through the triple joint complex. In this context, adjacent structures adopt different positions, and bone relations change, producing areas of higher or less contact and stress. The objective of this study was to use 3D distance maps (DMs) and coverage maps (CMs) from weightbearing CT (WBCT) images to assess subluxation across the Chopart joint in PCFD patients. We hypothesized that CMs would show decreased coverage indicative of subluxation through regions of the Chopart joint in PCFD patients when compared to controls.
Methods:
In this IRB-approved, retrospective case-control study, we analyzed WBCT data of 20 consecutive patients with flexible PCFD and 20 controls. Using principle component analysis, coverage area was divided into six regions on the talar head and 4 on the calcaneal-cuboid articular surface. Novel 3D distance mapping (DM) technique was used to objectively characterize joint coverage across the entire Chopart surface on both talus and calcaneus. Distance maps were measured in millimeters and colored to highlight covered areas. Distances less than 4mm were defined to be covered, while areas with distances greater than 4mm uncovered. Joint coverage was defined as percentage of articular area with DMs lower than 4 mm. Coverage Maps (CM) were built highlighting areas of coverage (teal) versus non-coverage (pink). The Foot and Ankle Offset (FAO) was used as a reference semi-automatic three-dimensional measurement. Comparisons were performed with independent t-tests, assuming unequal variances and p-values <.05 considered significant.
Results:
Changes in coverage percentages of PCFD cases relative to controls are indicated in the attached figure. The superomedial and the inferomedial regions of the talar head were found to have a 75% and 79% decrease in coverage in PCFD cases relative to the controls (ps<0.003). The medial side of the head had an overall increase in coverage (ps<0.002). On the calcaneus, the calcaneal-cuboid joint plantar region was found to have a significant coverage decrease of 12% relative to the controls (p=0.037), while the lateral quadrant observed a 13% increase (p=0.002). DMs evaluation showed no significant differences in the mean distances for either the calcaneocuboid or the talonavicular (ps>0.05). The FAO was found to be correlated with changes in talar and calcaneal coverages (rs=0.90; R2=0.81).
Conclusion:
Our results support the hypothesis that significant changes occur at the Chopart joint in early flexible PCFD cases. Increased coverage in the lateral region of the talar head and decreased coverage in the medial and plantar regions point to internal rotation of the talus indicating subluxation through the entire joint. This behavior was also translated in the calcaneal- cuboid, where plantar and medial areas had a decrease in coverage. Coverage 3D mapping enabled objective subluxation quantification through the Chopart joint in early-stage PCFD. These findings may assist clinical assessment of normal joint alignment restoration during PCFD corrections.
Atlas of the 2012 elections Archer, J. Clark; Watrel, Robert H; Davidson, Fiona ...
2014., 2014, 2014-09-26
eBook
Bringing together leading political geographers and political scientists, this authoritative atlas analyzes and maps the campaigns, primaries, general election, and key state referenda in the hotly ...contested 2012 elections. The contributors offer a comprehensive and detailed assessment of a wide array of election issues and results including presidential primaries; newspaper endorsements and campaign stops; the results of the presidential election at the regional and national levels; and key voting patterns by race and ethnicity, religion, occupational groups, age, and poverty. Moving beyond the national race, the atlas examines important senatorial and gubernatorial races and considers selected state referenda including the legalization of marijuana and same-sex marriage. Illustrated with nearly 200 meticulously drawn full-color maps, the atlas will be an essential reference and a fascinating resource for pundits, voters, campaign staffs, and political junkies alike.
In this lesson, you will learn how to display a georeferenced map from Map Warper in KnightLab’s StoryMap JS, an interactive web-based map and storytelling platform.
Category:
Basic Sciences/Biologics; Hindfoot; Midfoot/Forefoot
Introduction/Purpose:
Progressive collapsing foot deformity (PCFD), formerly termed Adult-Acquired Flatfoot Deformity (AAFD), is a ...complex 3D deformity characterized by peritalar subluxation (PTS) of the hindfoot through the triple joint complex. In this context, adjacent structures may adopt different positions and boney relations can change, producing areas increased contact or subluxation. The objective of this study was to use 3D distance maps (DMs) and coverage maps (CMs) from weightbearing CT (WBCT) images to assess subluxation across the Chopart joint in PCFD patients. We hypothesized that CMs would show decreased coverage indicative of subluxation through certain regions of the Chopart joint in PCFD patients when compared to the controls.
Methods:
In this IRB-approved, retrospective case-control study, we analyzed WBCT data of 18 consecutive patients with flexible PCFD and 10 controls. Using principle component analysis, candidate coverage area was divided into nine regions on the talar head and 4 regions on the calcaneal-cuboid (CC) articular surface. Novel 3D distance mapping (DM) technique was used to objectively characterize joint coverage across the entire Chopart joint surface on both the talus and calcaneus. Distance maps were measured in millimeters and colored to highlight covered areas. Areas with distances less than 4mm were defined to be covered, while areas with distances greater than 4mm were considered to be uncovered. Joint coverage was defined as percentage of articular area with DMs lower than 4 mm. Coverage Maps (CM) were created to highlight areas of coverage (teal) versus non- coverage (pink). Comparisons were performed with independent t-tests, assuming unequal variances. P values <.05 were considered significant.
Results:
Changes in coverage percentages of PCFD cases relative to controls are indicated in attached figure 1. The middle lateral region of the talar head was found to have a 9% increase in coverage in PCFD cases relative to the controls (p = 0.011). The plantar region of the calcaneal-cuboid joint was found to have a 18% decrease in coverage compared to the controls. Except for the dorsal medial regions, the medial side of the talar head saw overall decreases in coverage. However, these values were not statistically significant. On the calcaneus, the plantar region of the calcaneal-cuboid joint was found to have a significant coverage decrease of 18% relative to the controls (p = 0.017). There was also a decrease in coverage observed in the medial region of the calcaneal-cuboid joint and an increase in the dorsal and lateral areas.
Conclusion:
Our results support the occurrence of significant Chopart joint changes in early flexible PCFD. Increased lateral and decreased medial/plantar talar head coverage point to internal rotation and plantarflexion of the talus. Associated dorsal migration of the cuboid where plantar and medial areas have decreased coverage indicate subluxation through the entirety of the Chopart joint. Novel 3D coverage mapping enabled objective quantification of subluxation though the Chopart joint in early stage PCFD. These findings may assist clinical decision making regarding the restoration of normal joint alignment during PCFD corrections. Further studies are needed to establish thresholds of change associated with degeneration.
PDF