The primary aim of this study was to evaluate the differences in labial plate thickness in patients identified as having thin versus thick/average periodontal biotypes. The association between ...biotype and labial plate thickness was evaluated by correlating information obtained from cone beam computed tomographs, diagnostic impressions, and clinical examinations of the maxillary anterior teeth (canine to canine) in 60 patients. Compared to a thick/average biotype, a thin biotype was associated with thinner labial plate thickness (P < .001), narrower keratinized tissue width (P < .001), greater distance from the cementoenamel junction to the initial alveolar crest (P = .02), and probe visibility through the sulcus. There was no relationship between biotype and tooth height-to-width ratio or facial recession. Periodontal biotype is significantly related to labial plate thickness, alveolar crest position, keratinized tissue width, gingival architecture, and probe visibility but unrelated to facial recession.
Discoveries of bird-like theropod dinosaurs and basal avialans in recent decades have helped to put the iconic 'Urvogel' Archaeopteryx into context and have yielded important new data on the origin ...and early evolution of feathers. However, the biological context under which pennaceous feathers evolved is still debated. Here we describe a new specimen of Archaeopteryx with extensive feather preservation, not only on the wings and tail, but also on the body and legs. The new specimen shows that the entire body was covered in pennaceous feathers, and that the hindlimbs had long, symmetrical feathers along the tibiotarsus but short feathers on the tarsometatarsus. Furthermore, the wing plumage demonstrates that several recent interpretations are problematic. An analysis of the phylogenetic distribution of pennaceous feathers on the tail, hindlimb and arms of advanced maniraptorans and basal avialans strongly indicates that these structures evolved in a functional context other than flight, most probably in relation to display, as suggested by some previous studies. Pennaceous feathers thus represented an exaptation and were later, in several lineages and following different patterns, recruited for aerodynamic functions. This indicates that the origin of flight in avialans was more complex than previously thought and might have involved several convergent achievements of aerial abilities.
Introduction The purposes of this study were to determine and compare the intraexaminer and interexaminer reliabilities of commonly used cephalometric landmarks identified on digitized lateral ...cephalograms and formatted cone-beam computerized tomography (CBCT) images. Methods CBCT images from 10 randomly selected adolescent patients were obtained from the orthodontic records of a private practice. Measurement errors, and intraexaminer, and interexaminer reliability correlation coefficients (ICC) were obtained for all landmark coordinates. Results Intraexaminer and interexaminer reliabilities for all coordinates for most landmarks on the digital lateral cephalograms and CBCT images were greater than 0.9 (ICC value). The means of landmark locations differed by approximately 1 mm in most coordinates from the lateral cephalograms and were predominantly higher than 1 mm for all coordinates from the CBCT images. Conclusions Intraexaminer and interexaminer reliabilities were high for most landmarks. Coordinates with greater measurement errors in the lateral cephalograms (condylion, gonion, porion, mandibular incisor apex, and posterior nasal spine) were in structures without clearly defined borders. In the CBCT images, gonion, condylion, and porion were located on surfaces that were flat or curved, making it difficult to recognize a specific reference point. Other less reliable landmarks (anterior nasal spine, posterior nasal spine, mandibular incisor apex) were located in structures with lower densities and could not be visualized with 3-dimensional reconstruction; thus, they had high measurement errors.
At present, no consensus has been reached on the compartmental subdivision of the jugular foramen (JF), which can complicate surgical planning in this area and hinder understanding of foraminal tumor ...growth patterns. The extradural neural axis compartment (EDNAC) might aid in producing a standardized model in the future. In the present review, we have summarized the models of JF compartmentalization and analyzed how sound they are anatomically.
The present narrative review identified the key studies and supporting reports that had discussed, referenced, or first presented models of JF compartmentalization.
Three intraforaminal components serve as the basis for JF compartmentalization: the fibro-osseous bridge, neurovascular contents, and EDNAC. A total of 4 models have been proposed to date. These include the 2-part (bipartite) models by Hovelacque (1934) and Shapiro (1972) and the 3-part (tripartite) subdivisions by Katsuta (1997) and Bernard (2018).
The bipartite model has been criticized as being oversimplified and lacking surgical validity. However, support for this compartmentation has persisted despite the increasing popularity of the tripartite model. The 3-part subdivision of Bernard can be considered the most anatomically faithful model to date owing to the consideration of the dura and EDNAC. It is important that future studies consider the entire anatomy of the JF, which may generate an anatomically accurate and surgically applicable compartmental model.
Anatomical studies in animals have described multiple striatal circuits and suggested that sub-components of the striatum, although functionally related, project to distinct cortical areas. To date, ...anatomical investigations in humans have been limited by methodological constraints such that most of our knowledge of fronto-striatal networks relies on nonhuman primate studies. To better identify the fronto-striatal pathways in the human brain, we used Diffusion Tensor Imaging (DTI) tractography to reconstruct neural connections between the frontal cortex and the caudate nucleus and putamen in vivo. We demonstrate that the human caudate nucleus is interconnected with the prefrontal cortex, inferior and middle temporal gyrus, frontal eye fields, cerebellum and thalamus; the putamen is interconnected with the prefrontal cortex, primary motor area, primary somatosensory cortex, supplementary motor area, premotor area, cerebellum and thalamus. A connectivity-based seed classification analysis identified connections between the dorsolateral prefrontal areas (DLPFC) and the dorsal-posterior caudate nucleus and between the ventrolateral prefrontal areas (VLPFC) and the ventral-anterior caudate nucleus. For the putamen, connections exist between the supplementary motor area (SMA) and dorsal-posterior putamen while the premotor area projects to medial putamen, and the primary motor area to the lateral putamen. Identifying the anatomical organization of the fronto-striatal network has important implications for understanding basal ganglia function and associated disease processes.
By identifying homogeneity in bone and soft tissue covariation patterns in living hominids, it is possible to produce facial approximation methods with interspecies compatibility. These methods may ...be useful for producing facial approximations of fossil hominids that are more realistic than currently possible. In this study, we conducted an interspecific comparison of the nasomaxillary region in chimpanzees and modern humans with the aim of producing a method for predicting the positions of the nasal tips of Plio-Pleistocene hominids. We addressed this aim by first collecting and performing regression analyses of linear and angular measurements of nasal cavity length and inclination in modern humans (Homo sapiens; n = 72) and chimpanzees (Pan troglodytes; n = 19), and then performing a set of out-of-group tests. The first test was performed on four subjects that belonged to the same genus as the training sample, i.e., Homo (n = 2) and Pan (n = 2), and the second test, which functioned as an interspecies compatibility test, was performed on Pan paniscus (n = 1), Gorilla gorilla (n = 3), Pongo pygmaeus (n = 1), Pongo abelli (n = 1), Symphalangus syndactylus (n = 3), and Papio hamadryas (n = 3). We identified statistically significant correlations in both humans and chimpanzees with slopes that displayed homogeneity of covariation. Prediction formulae combining these data were found to be compatible with humans and chimpanzees as well as all other African great apes, i.e., bonobos and gorillas. The main conclusion that can be drawn from this study is that our set of regression models for approximating the position of the nasal tip are homogenous among humans and African apes, and can thus be reasonably extended to ancestors leading to these clades.
To review the dose limits and standardize the three-dimenional (3D) radiographic definition for the organs at risk (OARs) for thoracic radiotherapy (RT), including the lung, proximal bronchial tree, ...esophagus, spinal cord, ribs, and brachial plexus.
The present study was performed by representatives from the Radiation Therapy Oncology Group, European Organization for Research and Treatment of Cancer, and Soutwestern Oncology Group lung cancer committees. The dosimetric constraints of major multicenter trials of 3D-conformal RT and stereotactic body RT were reviewed and the challenges of 3D delineation of these OARs described. Using knowledge of the human anatomy and 3D radiographic correlation, draft atlases were generated by a radiation oncologist, medical physicist, dosimetrist, and radiologist from the United States and reviewed by a radiation oncologist and medical physicist from Europe. The atlases were then critically reviewed, discussed, and edited by another 10 radiation oncologists.
Three-dimensional descriptions of the lung, proximal bronchial tree, esophagus, spinal cord, ribs, and brachial plexus are presented. Two computed tomography atlases were developed: one for the middle and lower thoracic OARs (except for the heart) and one focusing on the brachial plexus for a patient positioned supine with their arms up for thoracic RT. The dosimetric limits of the key OARs are discussed.
We believe these atlases will allow us to define OARs with less variation and generate dosimetric data in a more consistent manner. This could help us study the effect of radiation on these OARs and guide high-quality clinical trials and individualized practice in 3D-conformal RT and stereotactic body RT.
The foot is a complex structure with many articulations and multiple degrees of freedom that play an important role in static posture and dynamic activities. The evolutionary development of the arch ...of the foot was coincident with the greater demands placed on the foot as humans began to run. The movement and stability of the arch is controlled by intrinsic and extrinsic muscles. However, the intrinsic muscles are largely ignored by clinicians and researchers. As such, these muscles are seldom addressed in rehabilitation programmes. Interventions for foot-related problems are more often directed at externally supporting the foot rather than training these muscles to function as they are designed. In this paper, we propose a novel paradigm for understanding the function of the foot. We begin with an overview of the evolution of the human foot with a focus on the development of the arch. This is followed by a description of the foot intrinsic muscles and their relationship to the extrinsic muscles. We draw the parallels between the small muscles of the trunk region that make up the lumbopelvic core and the intrinsic foot muscles, introducing the concept of the foot core. We then integrate the concept of the foot core into the assessment and treatment of the foot. Finally, we call for an increased awareness of the importance of the foot core stability to normal foot and lower extremity function.
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