Vitamin D and adolescent idiopathic scoliosis, should we stop the hype? A cross-sectional observational prospective study based on a geometric morphometrics approach.

PURPOSE: There is strong evidence supporting the presence of fluctuating asymmetry (FA) in Adolescents with Idiopathic Scoliosis (AIS). Additionally, recent research investigating the relationship between vitamin D and AIS found a relation between them. We hypothesize a negative correlation between FA and vitamin D. METHODS: We performed a surface scan of the torso of 53 AIS patients, a blood test to measure vitamin D and the radiographic Cobb angle. A correlation analysis between vitamin D and FA was carried out to test our hypothesis, and a regression of vitamin D on 3D shape was performed to observe shape differences between the vitamin D deficiency and insufficiency groups. RESULTS: There was no correlation between vitamin D and FA. We found a strong negative correlation between vitamin D and the Cobb angle only in the premenarche group (n = 7; r = - 0.92). Differences in shape were observed between the deficiency and insufficiency groups, and that differences were related to the width of the torso, but not the rotation or lateral flexion. CONCLUSIONS: Our results do not support the massive screening of vitamin D in AIS. Shape analysis revealed differences between the shape of the deficiency and insufficiency groups related to robustness. However, this finding had no relation with the scoliosis characteristics, it just reflected different body composition, and its importance should be explored in future.

Krapina atlases suggest a high prevalence of anatomical variations in the first cervical vertebra of Neanderthals.

The first cervical vertebra, atlas, and its anatomical variants have been widely studied in Homo sapiens. However, in Neanderthals, the presence of anatomical variants of the atlas has been very little studied until very recently. Only the Neanderthal group from the El Sidrón site (Spain) has been analysed with regard to the anatomical variants of the atlas. A high prevalence of anatomical variants has been described in this sample, which points to low genetic diversity in this Neanderthal group. Even so, the high prevalence of anatomical variations detected in El Sidrón Neanderthal atlases needs to be confirmed by analysing more Neanderthal remains. In this context, we analysed the possible presence of anatomical variants in the three Neanderthal atlases recovered from the Krapina site (Croatia) within the Neanderthal lineage. Two of the three Krapina atlases presented anatomical variations. One atlas (Krapina 98) had an unclosed transverse foramen and the other (Krapina 99) presented a non-fused anterior atlas arch. Moreover, an extended review of the bibliography also showed these anatomical variations in other Middle and Upper Pleistocene hominins, leading us to hypothesise that anatomical variations of the atlas had a higher prevalence in extinct hominins than in modern humans.

Comparative anatomy and 3D geometric morphometrics of the El Sidrón atlases (C1).

The first cervical vertebra (atlas, C1) is an important element of the vertebral column because it connects the cranial base with the cervical column, thus helping to maintain head posture and contributing to neck mobility. However, few atlases are preserved in the fossil record because of the fragility of this vertebra. Consequently, only eight well-preserved atlases from adult Neandertals have been recovered and described. Here, we present nine new atlas remains from the El Sidrón Neandertal site (Asturias, Spain), two of which (SD-1643 and SD-1605/1595) are sufficiently well preserved to allow for a detailed comparative and three-dimensional geometric morphometric analysis. We compared standard linear measurements of SD-1643 and SD-1605/1595 with those of other Neandertal atlases and carried out three-dimensional geometric morphometric analyses to compare size and shape of SD-1643 and SD-1605/1595 with those of 28 Pan (Pan troglodytes and Pan paniscus), a broad comparative sample of 55 anatomically modern humans from African and European populations, and other fossil hominins (Neandertals, Homo antecessor, Paranthropus boisei). The El Sidrón atlas fossils show typical features of the Neandertal atlas morphology, such as caudal projection of the anterior tubercle, gracility of both the posterior tubercle and the tuberosity for the insertion of the transverse ligament, and an anteroposteriorly elongated neural canal. Furthermore, when compared with atlases from the other taxa, Neandertals exhibit species-specific features of atlas morphology including a relatively lower lateral mass height, relatively narrower transverse foramina, and flatter and more horizontally oriented articular facets. Some of these features fit with previous suggestions of shorter overall length of the cervical spine and potential differences in craniocervical posture and mobility. Our results may support a different spinopelvic alignment in this species, as the atlas morphology suggests reduced cervical lordosis.

The evolution, form and function of the human respiratory system.

This paper presents an updated view on the morphological and functional significance of the human respiratory system in the context of human evolutionary anatomy. While usually the respiratory system is treated either from a craniofacial perspective, mostly in the context of nasal evolution and air-conditioning, or from a postcranial perspective featuring on overall thoracic shape changes, here we pursue a holistic perspective on the form, function, integration, and evolutionary change of the entire organismal system in hominins. We first present a brief review of the most important morphological structures, their function, and its potential integration and interaction with the nasal cavity and thoracic skeleton. This is followed by an overview of the most important improvements in methods for the comparative study in recent humans and fossil hominins. We then overview and list a compendium of hominin fossil material currently available for the study. We propose four functional categories of hominin respiratory system configurations that differ potentially with respect to size, shape, biomechanics and/or bioenergetics. Finally, we discuss these and speculate on possible ways for future research into an anatomical system that, despite its under-investigated status, is central to the understanding of the form and functions of the hominin organism and its paleobiology.

Geometric Morphometrics of the human cervical vertebrae: sexual and population variations.

This study aims to carry out the first geometric morphometric analysis of the 3D size and shape of the full series of cervical vertebrae delving into variability related to sex and population background. For this reason, we analyzed the cervical vertebrae of both males and females belonging to Europeans, Africans, and Greenland Inuit. We 3D-scanned a total of 219 cervical vertebrae of males and females of three different modern human populations (European, African, and Inuit). A minimum of 72 landmarks and curve semilandmarks were positioned in each of the 3D vertebral models. Landmark configurations were analyzed following the standards of 3D Geometric Morphometrics to test for size and shape differences related to sex or population variation. Results show that male cervical vertebrae are consistently larger than in females while no regular shape differences are observed between males and females in any of the populations. Sex differences in cervical lordosis are thus not supported at the skeletal level of the 3D shape. On the other hand, there is no evidence for population-specific differences in size while shape does vary considerably, possibly also in relation to eco-geographic factors of overall trunk shape. Cervical vertebrae in cold-adapted Inuit were consistently shorter than in Europeans and Africans. The cervical spine may show a different pattern than the thoracic and lumbar spine, which might be related to stronger integration with the cranium, head mobility, and soft-tissue dependence. Our findings suggest that morpho-functional interpretations of the cervical spine based on vertebral skeletal morphology requires caution.

Association between ribs shape and pulmonary function in patients with Osteogenesis Imperfecta.

The aim of the present study was to test the hypothesis that ribs shape changes in patients with OI are more relevant for respiratory function than thoracic spine shape. We used 3D geometric morphometrics to quantify rib cage morphology in OI patients and controls, and to investigate its relationship with forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1), expressed as absolute value and as percentage of predicted value (% pred). Regression analyses on the full sample showed a significant relation between rib shape and FEV1, FVC and FVC % pred whereas thoracic spine shape was not related to any parameter. Subsequent regression analyses on OI patients confirmed significant relations between dynamic lung volumes and rib shape changes. Lower FVC and FEV1 values are identified in OI patients that present more horizontally aligned ribs, a greater antero-posterior depth due to extreme transverse curve at rib angles and a strong spine invagination, greater asymmetry, and a vertically short, thoraco-lumbar spine, which is relatively straight in at levels 1-8 and shows a marked kyphosis in the thoraco-lumbar transition. Our research seems to support that ribs shape is more relevant for ventilator mechanics in OI patients than the spine shape.

Rib cage anatomy in Homo erectus suggests a recent evolutionary origin of modern human body shape.

The tall and narrow body shape of anatomically modern humans (Homo sapiens) evolved via changes in the thorax, pelvis and limbs. It is debated, however, whether these modifications first evolved together in African Homo erectus, or whether H. erectus had a more primitive body shape that was distinct from both the more ape-like Australopithecus species and H. sapiens. Here we present the first quantitative three-dimensional reconstruction of the thorax of the juvenile H. erectus skeleton, KNM-WT 15000, from Nariokotome, Kenya, along with its estimated adult rib cage, for comparison with H. sapiens and the Kebara 2 Neanderthal. Our three-dimensional reconstruction demonstrates a short, mediolaterally wide and anteroposteriorly deep thorax in KNM-WT 15000 that differs considerably from the much shallower thorax of H. sapiens, pointing to a recent evolutionary origin of fully modern human body shape. The large respiratory capacity of KNM-WT 15000 is compatible with the relatively stocky, more primitive, body shape of H. erectus.

Workflows in a Virtual Morphology Lab: 3D scanning, measuring, and printing.

The aim of this paper is to give a practical overview, showing how recent available digital technology can be combined to build a laboratory capable to produce 3D (and reproduce in 3D) anatomical models for research, teaching and museum exhibitions on topics related to anatomy, morphology in natural sciences, biology and medicine. We present workflows in our Virtual Morphology Lab that can be used for research, training (museum, academic), and external service. We first review different surface scanning equipment and post-processing techniques that are useful for scanning in museum collections and provide technical recommendations for hard- and software as well as storing media on the web. This section is followed by an overview of available software packages for rigorous and effective 3D measurements of landmarks and sliding semi-landmarks, providing extensive supplementary information with guiding manuals for self-teaching in these cutting-edge but complicated research methods. We review briefly most recent work on virtual GM and describe ways for representing results in form of 3D images and 3D prints (outputs). The last part is dedicated to a summary of our experience in 3D-printing using FDM technology of differently sized printers and thermoplastic materials. Finally, we discuss the above-described workflows and its potential applications in research (paleo, biomedical), teaching and museums pedagogics.