Morphometric analysis of the hominin talus: Evolutionary and functional implications.

The adoption of bipedalism is a key benchmark in human evolution that has impacted talar morphology. Here, we investigate talar morphological variability in extinct and extant hominins using a 3D geometric morphometric approach. The evolutionary timing and appearance of modern human-like features and their contributions to bipedal locomotion were evaluated on the talus as a whole, each articular facet separately, and multiple combinations of facets. Distinctive suites of features are consistently present in all fossil hominins, despite the presence of substantial interspecific variation, suggesting a potential connection of these suites to bipedal gait. A modern human-like condition evolved in navicular and lateral malleolar facets early in the hominin lineage compared with other facets, which demonstrate more complex morphological variation within Homininae. Interestingly, navicular facet morphology of Australopithecus afarensis is derived in the direction of Homo, whereas more recent hominin species such as Australopithecus africanus and Australopithecus sediba retain more primitive states in this facet. Combining the navicular facet with the trochlea and the posterior calcaneal facet as a functional suite, however, distinguishes Australopithecus from Homo in that the medial longitudinal arch had not fully developed in the former. Our results suggest that a more everted foot and stiffer medial midtarsal region are adaptations that coincide with the emergence of bipedalism, whereas a high medial longitudinal arch emerges later in time, within Homo. This study provides novel insights into the emergence of talar morphological traits linked to bipedalism and its transition from a facultative to an obligate condition.

The influence of mobility strategy on the modern human talus.

OBJECTIVES: The primate talus is known to have a shape that varies according to differences in locomotion and substrate use. While the modern human talus is morphologically specialized for bipedal walking, relatively little is known on how its morphology varies in relation to cultural and environmental differences across time. Here we compare tali of modern human populations with different subsistence economies and lifestyles to explore how cultural practices and environmental factors influence external talar shape. MATERIALS AND METHODS: The sample consists of digital models of 142 tali from 11 archaeological and post-industrial modern human groups. Talar morphology was investigated through 3D (semi)landmark based geometric morphometric methods. RESULTS: Our results show distinct differences between highly mobile hunter-gatherers and more sedentary groups belonging to a mixed post-agricultural/industrial background. Hunter-gatherers exhibit a more "flexible" talar shape, everted posture, and a more robust and medially oriented talar neck/head, which we interpret as reflecting long-distance walking strictly performed barefoot, or wearing minimalistic footwear, along uneven ground. The talus of the post-industrial population exhibits a "stable" profile, neutral posture, and a less robust and orthogonally oriented talar neck/head, which we interpret as a consequence of sedentary lifestyle and use of stiff footwear. DISCUSSION: We suggest that talar morphological variation is related to the adoption of constraining footwear in post-industrial society, which reduces ankle range of motion. This contrasts with hunter-gatherers, where talar shape shows a more flexible profile, likely resulting from a lack of footwear while traversing uneven terrain. We conclude that modern human tali vary with differences in locomotor and cultural behavior.

Trajectory analysis among African hominoids can provide insights into genetic and epigenetic influences during ontogeny.

OBJECTIVES: Prior examination of the ontogeny of Hominoid talo-crural joint morphology using Singular Warp analysis suggested both a genetic and epigenetic signal during development. This question is examined using trajectory analysis and its implications for the Hominin fossil record explored. MATERIALS AND METHODS: Trajectory analysis was used to examine talo-crural joint shape at different molar eruption stages during development among a cohort of 221 specimens of Homo sapiens, Gorilla gorilla, Pan troglodytes, and Pan paniscus. Trajectory length, angle, and shape were compared among species. Trajectories that showed a consistent pattern of shape change were predicted to show a genetic signal, while change in that pattern an epigenetic signal. RESULTS: The trajectories of all four hominoid tali were consistent during M1-M2 development, but there was a change in Pan paniscus alone at M2-M3. The tibial trajectories were again consistent in M1-M2 development, however, only Pan paniscus persisted in this trajectory at M2-M3 while the other three changed. DISCUSSION: Trajectory analysis demonstrated an epigenetic signal in Pan paniscus in the talus and among the other three hominoids in the tibia. Behavioral (epigenetic) changes may impact hominoid ankle shape in extant species. These changes may reflect differences in locomotor repertoire altering shape, as has been suggested in the Hominin fossil record. Further examination of closely related hominoid species may provide insights into potential behavioral influences in the rapid change and diversity of Hominin talo-crural shape in the Plio-pleistocene.

The ontogeny of talo-crural appositional articular morphology among catarrhine taxa: adult shape reflects substrate use.

The upper ankle joint forms a single articular plane between organism and the foot and substrate. Singular warp analysis shows that its shape reflects substrate use. This study explores whether the differences in shape are genetic with a developmental trajectory evident during ontogeny or epigenetic and the result of substrate use by the individual. A total of 418 matched distal tibial and proximal talar landmarked surfaces from adult and subadult specimens from 12 diverse catarrhine taxa were studied. Specimens were grouped by molar eruption (M1, M2, and M3) for comparative analysis. Generalized Procrustes analysis, multivariate regression, relative warp analysis, singular warp analysis, and permutation tests were used. Singular warp analysis for the entire cohort was highly significant in the first singular warp, with the adult taxa sorting by substrate use. All 173 subadults clustered with an adult "arboreal" shape profile. Among Hominoidea, adults (M3) sorted by substrate use with Pan paniscus and Hylobatidae assuming an "arboreal" shape separate from Pan troglodytes and the remaining taxa with "terrestrial" shape. Cercopithecoid adults sorted by substrate use as well, with the M3 specimens of Papio hamadryas and Macaca thibetana demonstrating a "terrestrial" shape. Differences in mode of locomotion did not affect the findings in the first singular warp. Results confirmed the convergence of talo-crural shape among superfamilies based on substrate use and divergence in shape within Pan and Macaca, based on substrate use. The shape differences among adults (M3) are consistent with a plastic response to the behavioral stimulus of substrate use.

Exploring sexual dimorphism of the modern human talus through geometric morphometric methods.

Sex determination is a pivotal step in forensic and bioarchaeological fields. Generally, scholars focus on metric or qualitative morphological features, but in the last few years several contributions have applied geometric-morphometric (GM) techniques to overcome limitations of traditional approaches. In this study, we explore sexual dimorphism in modern human tali from three early 20th century populations (Sassari and Bologna, Italy; New York, USA) at intra- and interspecific population levels using geometric morphometric (GM) methods. Statistical analyses were performed using shape, form, and size variables. Our results do not show significant differences in shape between males and females, either considering the pooled sample or the individual populations. Differences in talar morphology due to sexual dimorphism are mainly related to allometry, i.e. size-related changes of morphological traits. Discriminant function analysis using form space Principal Components and centroid size correctly classify between 87.7% and 97.2% of the individuals. The result is similar using the pooled sample or the individual population, except for a diminished outcome for the New York group (from 73.9% to 78.2%). Finally, a talus from the Bologna sample (not included in the previous analysis) with known sex was selected to run a virtual resection, followed by two digital reconstructions based on the mean shape of both the pooled sample and the Bologna sample, respectively. The reconstructed talus was correctly classified with a Ppost between 99.9% and 100%, demonstrating that GM is a valuable tool to cope with fragmentary tali, which is a common occurrence in forensic and bioarchaeological contexts.

Phylogenetic Perspectives on Catarrhine Talo-Crural Joint Phenotypic Plasticity.

Previous investigations of the primate talo-crural joint (TCJ; specifically on the talus and distal tibia) have demonstrated that substrate preference significantly influences morphology, but this association is not necessarily found in subadults. This has been interpreted as the result of a plastic, behaviorally induced response of bone due to substrate use. In this investigation, we use geometric morphometric and phylogenetic comparative methods to investigate ontogenetic phenotypic plasticity in the catarrhine TCJ. Osteological specimens from four African hominoid and four cercopithecid species, divided into subadult and adult developmental stages based on molar eruption, formed the study group. We tested for phylogenetic signal in the shape of both the talar and tibial articular surfaces, at both developmental stages. We then used phylomorphospaces to examine the evolution of shape differences at each developmental stage for each element, and to determine if substrate usage is associated with shape in this phylogenetic context. A significant phylogenetic signal was found for both articular surfaces in subadults, but not adults. In phylomorphospace, both talar and tibial articular morphologies show an association with substrate preference in adults, but not in subadults. Our results provide confirmation of the significant effect of habitual substrate usage and the consequences of bone remodeling during ontogeny on the shape and presentation of the TCJ. These results also suggest caution when using adult talo-tibial shapes to evaluate phylogenetic relationships as TCJ morphology can be considered as a palimpsest, with substrate usage overwriting phylogenetic information in adult specimens. Anat Rec, 302:1977-1984, 2019. © 2019 American Association for Anatomy.

Advances in Paedriatric Cardiac Surgery.

Treatment of congenital cardiac disease has been marked in the recent decade by a movement towards treatment in early infancy, the development of techniques of radical palliation for conditions previously inoperable and the emergence of transplantation as a viable alternative.

The appositional articular morphology of the talo-crural joint: the influence of substrate use on joint shape.

The appositional articular morphology of the talo-crural joint is the third component of the joint complex. It is a site of internal integration of this highly stable functional evolutionary unit. Prior studies of the other two components, tibia and talus, demonstrated that substrate preference influenced their articular shape. This effect was unrelated to physical attributes (size and mass) and phylogeny (superfamily). The effect of this behavioral factor, substrate preference, on shape and integration of the appositional articular morphology was investigated. Two hundred forty-five matched distal tibial and proximal talar landmarked surfaces from 12 diverse Catarrhine taxa were studied. Shape effects due to the same factors previously studied were examined in the tibial and talar subsets and were highly significant (P < 0.0001). These were assessed using Multivariate Regression and Relative Warps analysis, and Permutation tests, with results consistent with prior unmatched cohorts. Substrate preference influenced shape and was unrelated to the other factors across taxa. Singular Warp analysis of the cross-covariance matrix revealed sorting of taxa by substrate use, unrelated to physical attributes and phylogeny. Finally, the sorting demonstrated a signal of convergent evolution among distantly related taxa and divergent evolution among closely related taxa reflecting substrate use. Results were consistent with a behavioral influence, substrate use, affecting articular shape and integration in this highly stable functional evolutionary unit, and signals with evolutionary implications.

The shape and presentation of the Catarrhine talus: a geometric morphometric analysis.

The distal component of the talo-crural joint, the talus, was compared, using geometric morphometrics, in 219 specimens from nine extant taxa to identify differences in shape and the factors influencing them. The specimens were laser scanned, digitally reconstructed, and landmarked. The whole talus, proximal and distal articular facet subgroups were analyzed using Generalized Procrustes analysis, linear regression, principal component analysis, analysis of percent variance, dot-product vector analysis, and pair-wise permutation tests to evaluate shape, and were visualized by TPS deformation of an exemplar surface. Significant percentages of shape variation among taxa were due to body mass, talar size, superfamily, and substrate preference. Shape and presentational morphology associated with these factors were documented, along with the similarities and differences among individual taxa. Nearly all taxa were significantly different in overall, proximal and distal shapes. The most important factors influencing whole talar shape were log centroid size and substrate preference. Substrate preference was also the most important factor defining proximal articular morphology and unrelated to other factor such as mass, while distal articular morphology was influenced by superfamily (head angle and shape). Results demonstrated that substrate preference and superfamily significantly influenced distal presentation, while substrate preference influenced proximal articular shape.

Geometric morphometric analysis of tibial shape and presentation among Catarrhine taxa.

The proximal component of the talo-crural joint, the tibia, was compared, using geometric morphometrics, in 240 specimens from 10 extant taxa to identify differences in shape and the factors influencing them. The specimens were laser scanned, digitally reconstructed, and landmarked. Regression analysis was used to evaluate tibial shape, and significant amounts of shape variation among taxa were due to body mass, tibial size, superfamily, and substrate preference in the whole tibia, as well as, separate analysis of the distal tibial articular facets, and the medial malleolar facet. The most important factor for whole tibial shape was tibial robusticity, which closely correlated with body mass. However, substrate preference was also a significant factor in tibial shape and independent from body mass. Substrate preference was also the most important factor defining distal articular morphology. Principal components analysis and pairwise permutation tests were used to compare differences in morphology among taxa. Nearly all were significantly different in overall tibial shape, and distal morphology. Shape and presentational morphology associated with body mass, tibial size, superfamily, and substrate preference were identified, along with the similarities and differences among individual taxa. These were visualized by TPS deformation of an exemplar surface. Relationships among these factors were assessed with their dot-product. Results demonstrated that size significantly influenced proximal presentation, while substrate preference influenced articular morphology.

Tronco arterioso: seguimiento postquirúrgico / Truncus arteriusus post-surgical follow-up

Sin tratamiento, el 60% de los troncos arteriosos fallece dentro de los seis meses de vida, siendo muy comprometido el pronóstico del 40% restante por la insuficiencia cardíaca o por la enfermedad vascular pulmonar hipertensiva. Esto justifica la intervención quirúrgica precoz. Fueron operados 106 pacientes menores de seis meses: 14 con insuficiencia troncal severa. Se efectuó la técnica de Rastelli con tubo valvulado de Hancock; fallecieron 11 en el postoperatorio inmediato (8 con insuficiencia troncal severa) y 3 tardíamente por endocarditis. Otros 4 presentaron endocarditis, habiendo sido operados dos con éxito; los dos restantes fueron exitosamente tratados con antibióticos. Fueron reoperados 71 pacientes para cambiar el conducto y 3 requirieron un segundo cambio. En conclusión, la baja mortalidad operatoria justifica la indicación de la cirugía a una edad de uno a cuatro meses