Publications by authors named "Shahed Nalla"

20 Publications

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Assessing thoraco-pelvic covariation in Homo sapiens and Pan troglodytes: A 3D geometric morphometric approach.

Am J Phys Anthropol 2020 11 30;173(3):514-534. Epub 2020 Aug 30.

Departamento de Paleobiología, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain.

Objectives: Understanding thoraco-pelvic integration in Homo sapiens and their closest living relatives (genus Pan) is of great importance within the context of human body shape evolution. However, studies assessing thoraco-pelvic covariation across Hominoidea species are scarce, although recent research would suggest shared covariation patterns in humans and chimpanzees but also species-specific features, with sexual dimorphism and allometry influencing thoraco-pelvic covariation in these taxa differently.

Material And Methods: N = 30 adult H. sapiens and N = 10 adult Pan troglodytes torso 3D models were analyzed using 3D geometric morphometrics and linear measurements. Effects of sexual dimorphism and allometry on thoraco-pelvic covariation were assessed via regression analyses, and patterns of thoraco-pelvic covariation in humans and chimpanzees were computed via Two-Block Partial Least Squares analyses.

Results: Results confirm the existence of common aspects of thoraco-pelvic covariation in humans and chimpanzees, and also species-specific covariation in H. sapiens that is strongly influenced by sexual dimorphism and allometry. Species-specific covariation patterns in chimpanzees could not be confirmed because of the small sample size, but metrics point to a correspondence between the most caudal ribs and iliac crest morphology that would be irrespective of sex.

Conclusions: This study suggests that humans and chimpanzees share common aspects of thoraco-pelvic covariation but might differ in others. In humans, torso integration is strongly influenced by sexual dimorphism and allometry, whilst in chimpanzees it may not be. This study also highlights the importance not only of torso widths but also of torso depths when describing patterns of thoraco-pelvic covariation in primates. Larger samples are necessary to support these interpretations.
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http://dx.doi.org/10.1002/ajpa.24103DOI Listing
November 2020

Three-dimensional geometric morphometrics of thorax-pelvis covariation and its potential for predicting the thorax morphology: A case study on Kebara 2 Neandertal.

J Hum Evol 2020 10 14;147:102854. Epub 2020 Aug 14.

Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), J.G. Abascal 2, 28006, Madrid, Spain.

The skeletal torso is a complex structure of outstanding importance in understanding human body shape evolution, but reconstruction usually entails an element of subjectivity as researchers apply their own anatomical expertise to the process. Among different fossil reconstruction methods, 3D geometric morphometric techniques have been increasingly used in the last decades. Two-block partial least squares analysis has shown great potential for predicting missing elements by exploiting the covariation between two structures (blocks) in a reference sample: one block can be predicted from the other one based on the strength of covariation between blocks. The first aim of this study is to test whether this predictive approach can be used for predicting thorax morphologies from pelvis morphologies within adult Homo sapiens reference samples with known covariation between the thorax and the pelvis. The second aim is to apply this method to Kebara 2 Neandertal (Israel, ∼60 ka) to predict its thorax morphology using two different pelvis reconstructions as predictors. We measured 134 true landmarks, 720 curve semilandmarks, and 160 surface semilandmarks on 60 3D virtual torso models segmented from CT scans. We conducted three two-block partial least squares analyses between the thorax (block 1) and the pelvis (block 2) based on the H. sapiens reference samples after performing generalized Procrustes superimposition on each block separately. Comparisons of these predictions in full shape space by means of Procrustes distances show that the male-only predictive model yields the most reliable predictions within modern humans. In addition, Kebara 2 thorax predictions based on this model concur with the thorax morphology proposed for Neandertals. The method presented here does not aim to replace other techniques, but to rather complement them through quantitative prediction of a virtual 'scaffold' to articulate the thoracic fossil elements, thus extending the potential of missing data estimation beyond the methods proposed in previous works.
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http://dx.doi.org/10.1016/j.jhevol.2020.102854DOI Listing
October 2020

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

Nat Ecol Evol 2020 09 6;4(9):1178-1187. Epub 2020 Jul 6.

Centre for Human Evolution Research, Department of Earth Sciences, The Natural History Museum, London, UK.

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.
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http://dx.doi.org/10.1038/s41559-020-1240-4DOI Listing
September 2020

3D geometric morphometric analysis of variation in the human lumbar spine.

Am J Phys Anthropol 2019 11 15;170(3):361-372. Epub 2019 Aug 15.

Paleoanthropology Group, Museo Nacional de Ciencias Naturales (CSIC), Madrid, Spain.

Objectives: The shape of the human lumbar spine is considered to be a consequence of erect posture. In addition, several other factors such as sexual dimorphism and variation in genetic backgrounds also influence lumbar vertebral morphology. Here we use 3D geometric morphometrics (GM) to analyze the 3D morphology of the lumbar spine in different human populations, exploring those potential causes of variation.

Material And Methods: We collected 390 (semi) landmarks from 3D models of the CT scans of lumbar spines of seven males and nine females from a Mediterranean population (Spain, Israel) and seven males and either females from a South African population for geometric morphometric (GM) analysis. We carried out Generalized Procrustes Analysis, Principal Components, and Regression analyses to evaluate shape variation; and complemented these analyses with the Cobb Method.

Results: The Mediterranean sample was considerably more lordotic than the South African sample. In both populations, female lumbar spines showed proportionally narrower and more craniocaudally elongated lumbar segments than in males. In addition, the point of maximum curvature in females tended to be located more inferiorly than in males.

Discussion: Our results show that sexual dimorphism is an important factor of lumbar spine variation that mainly affects features of lumbar spine robustness (height proportions) and the structure-but not the degree-of its curvature. Differences in lordosis, however, are clearer at the inter-population level. This reflects previous conflicting studies casting doubts on pregnancy as an adaptive factor influencing lordosis. Other factors, for example, shape of the individual lumbar vertebrae and intervertebral discs and their relative proportions within the lumbar spine should be considered when exploring variation in vertebral column morphology.
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http://dx.doi.org/10.1002/ajpa.23918DOI Listing
November 2019

Possible Clinical Implications of Geographic Differences in Prevalence of Double Transverse Foramen.

World Neurosurg 2019 Jun 1;126:e570-e572. Epub 2019 Mar 1.

GIAVAL Research Group, Department of Anatomy and Human Embryology, University of Valencia, Faculty of Medicine, Valencia, Spain.

Background: The double transverse foramen (DBLTF) is a cervical spine anatomic variant. Current literature has presented prevalence values of DBLTF in Caucasian Mediterranean subjects that seem to be higher than those observed in other samples of subjects. Therefore we aimed to test if Caucasian Mediterranean subjects present a higher prevalence of the DBLTF than sub-Saharan African subjects.

Methods: We analyzed the presence of DBLTF in cervical spines of 100 skeletons from Caucasian Mediterranean subjects and 91 skeletons from sub-Saharan African subjects, resulting in a total of 1337 cervical vertebrae having been studied.

Results: No DBLTF was found in vertebrae C1, C2, and C3. The pattern of prevalence observed in all samples analyzed indicated the prevalence ranged from exhibiting the most to the least prevalence as C6 > C5 > C7 > C4. The sub-Saharan African subjects presented a significant reduced DBLTF prevalence of 2.2%, 14.3%, 19.8%, and 3.3% in C4 (P = 0.043), C5 (P = 0.004), C6 (P < 0.001), and C7 (P = 0.041), respectively, than that presented by Caucasian Mediterranean subjects (9.0%, 32.0%, 45.0%, 11.0% in C4, C5, C6, and C7, respectively).

Conclusions: Our study has revealed that this anatomic variation is more frequently found in Caucasian Mediterranean subjects than in sub-Saharan African subjects.
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http://dx.doi.org/10.1016/j.wneu.2019.02.096DOI Listing
June 2019

The Retrotransverse Foramen of the Atlas Is not a Modern Anatomic Variation.

World Neurosurg 2019 Mar 14;123:174-176. Epub 2018 Dec 14.

Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Auckland Park, South Africa.

Background: The retrotransverse foramen (RTF) is a nonmetric variant of the atlas vertebra that consists of an abnormal accessory foramen located on the posterior root of the transverse process and it extends from the posterior root of the transverse process to the root of the posterior arch. Its presence has been related to regional variations of the venous circulation. It is currently unknown whether the RTF is a modern or an ancient anatomic variation.

Case Description: We analyzed the skeletal remains from the late-ancient Roman necropolis (II-VI centuries ad) of La Boatella (Valencia, Spain) and we found a well-preserved individual skeleton that presented with a left retrotransverse foramen in C1.

Conclusions: The RTF is not a modern anatomic variation. As a result, ancient individuals had the same modifications in the regional circulation as modern subjects present today.
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http://dx.doi.org/10.1016/j.wneu.2018.11.241DOI Listing
March 2019

The torso integration hypothesis revisited in Homo sapiens: Contributions to the understanding of hominin body shape evolution.

Am J Phys Anthropol 2018 12 27;167(4):777-790. Epub 2018 Sep 27.

Paleoanthropology Group, Museo Nacional de Ciencias Naturales, Madrid, Spain.

Objectives: Lower thoracic widths and curvatures track upper pelvic widths and iliac blades curvatures in hominins and other primates (torso integration hypothesis). However, recent studies suggest that sexual dimorphism could challenge this assumption in Homo sapiens. We test the torso integration hypothesis in two modern human populations, both considering and excluding the effect of sexual dimorphism. We further assess covariation patterns between different thoracic and pelvic levels, and we explore the allometric effects on torso shape variation.

Material And Methods: A sex-balanced sample of 50 anatomically connected torsos (25 Mediterraneans, 25 Sub-Saharan Africans) was segmented from computed tomography scans. We compared the maximum medio-lateral width at seventh-ninth rib levels with pelvic bi-iliac breadth in males and females within both populations. We measured 1,030 (semi)landmarks on 3D torso models, and torso shape variation, mean size and shape comparisons, thoraco-pelvic covariation and allometric effects were quantified through 3D geometric morphometrics.

Results: Females show narrow thoraces and wide pelves and males show wide thoraces and narrow pelves, although this trend is more evident in Mediterraneans than in Sub-Saharans. Equal thoracic and pelvic widths, depths and curvatures were found in absence of sexual dimorphism. The highest strength of covariation was found between the lowest rib levels and the ilia, and allometric analyses showed that smaller torsos were wider than larger torsos.

Conclusions: This is the first study testing statistically the torso integration hypothesis in anatomically connected torsos. We propose a new and more complex torso integration model in H. sapiens with sexual dimorphism leading to different thoracic and pelvic widths and curvatures. These findings have important implications in hominin body shape reconstructions.
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http://dx.doi.org/10.1002/ajpa.23705DOI Listing
December 2018

Description and analysis of three Homo naledi incudes from the Dinaledi Chamber, Rising Star cave (South Africa).

J Hum Evol 2018 09 9;122:146-155. Epub 2018 Jul 9.

Evolutionary Studies Institute, University of the Witwatersrand, 210A Palaeosciences Centre East Campus, Braamfontein, Johannesburg, Private Bag 3 WIT 2050, South Africa.

This study describes three incudes recovered from the Dinaledi Chamber in the Rising Star cave system in South Africa. All three bones were recovered during sieving of excavated sediments and likely represent three Homo naledi individuals. Morphologically and metrically, the Dinaledi ossicles resemble those of chimpanzees and Paranthropus robustus more than they do later members of the genus Homo, and fall outside of the modern human range of variation in several dimensions. Despite this, when overall size is considered, the functional lengths in H. naledi and P. robustus are very similar to those predicted for a human with a similar-sized incus. In this sense, both taxa seem to show a relatively elongated functional length, distinguishing them from chimpanzees. The functional length in H. naledi is slightly longer in absolute terms than in P. robustus, suggesting H. naledi may already show a slight increase in functional length compared with early hominins. While H. naledi lacks the more open angle between the long and short processes found in modern humans, considered a derived feature within the genus Homo, the value in H. naledi is similar to that predicted for a hominoid with a similar-sized incus. Principal components analysis of size-standardized variables shows H. naledi falling outside of the recent human range of variation, but within the confidence ellipse for gorillas. Phylogenetic polarity is complicated by the absence of incus data from early members of the genus Homo, but the generally primitive nature of the H. naledi incudes is consistent with other primitive features of the species, such as the very small cranial capacity. These ossicles add significantly to the understanding of incus variation in hominins and provide important new data on the morphology and taxonomic affinities of H. naledi.
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http://dx.doi.org/10.1016/j.jhevol.2018.06.008DOI Listing
September 2018

Prevalence of anatomic variations of the atlas vertebra.

Spine J 2018 11 28;18(11):2102-2111. Epub 2018 Jun 28.

Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, 7304e, John Orr Building, Johannesburg, South Africa.

Background Context: The retrotransverse foramen (RTF), arcuate foramen (AF), unclosed transverse foramen (UTF) and posterior atlas arch defects (PAAD) are anatomic variations of the atlas vertebra that surgeons must be aware of before spine surgery is performed.

Purpose: To analyze the prevalence of the AF, RTF, UTF, and PAAD.

Study Design: Ex-vivo anatomical study.

Patient Sample: Two hundred eighteen atlas vertebrae obtained from 100 Caucasian subjects and 118 sub-Saharan African subjects (48 Sotho subjects, 35 Xhosa subjects and 35 Zulu subjects).

Methods: We studied 218 atlas vertebrae from skeletons of the Raymond A. Dart Collection in order to analyze the prevalence of AF, RTF, UTF, and PAAD in both Caucasian and sub-Saharan African subjects.

Outcome Measures: Not applicable.

Results: Sixty-nine (31.2%) atlases presented anatomical variants: 64 (29.3%) presented one anatomical variant, 4 (1.8%) presented two, and 1 (0.5%) presented three. AF, RTF, UTF, Type A and Type E defects were present in 35 (16.1%), 17 (7.8%), 17 (7.8%), 5 (2.3%), and 1 (0.5%) vertebrae, respectively. The vertebrae with two anatomical variants presented a bilateral UTF and a Type A defect, a bilateral AF and a Type A defect, a right UTF and a left AF, and a right UTF and a Type E defect. The vertebra with three anatomical variants presented a bilateral RTF, a left UTF, and a left AF. No sex differences in prevalence of the RTF (p=.775), AF (p=.605), UTF (p=.408) and Type A defects (p=1.000) were found in the sub-Saharan African and Caucasian groups (RTF, p=.306; AF, p=.346; UTF, p=.121; Type A defects, p=.561). Comparison between the sub-Saharan African (all subjects) and the Caucasian group revealed no differences in the UTF (p=.105), AF (p=.144), RTF (p=.542) and Type A defects (p=.521) prevalence. Also, no differences in the prevalence of the UTF (p=.515), AF (p=.278), and RTF (p=.857) between Zulu, Xhosa and Sotho subjects were found. Neither were found sex differences in the prevalence of UTF, RTF and AF in Zulu (p=.805, p=.234, p=.129), Xhosa (p=.269, p=.181, p=.309), and Sotho subjects (p=.062, p=.590, p=.106).

Conclusions: The present study has revealed no sex differences in the prevalence of AF, UTF, RTF or PAAD in both Caucasian and sub-Saharan African subjects. This research has also indicated no differences in the prevalence of the UTF, AF and RTF between Zulu, Xhosa and Sotho subjects. In addition, this study has revealed no differences in the Type A, UTF, AF, and RTF prevalence between the sub-Saharan African (all subjects) and the Caucasian subjects. These variations may be known by surgeons before spine surgery for better planning.
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http://dx.doi.org/10.1016/j.spinee.2018.06.352DOI Listing
November 2018

Atlases with Arcuate Foramen Present Cortical Bone Thickening That May Contribute to Lower Fracture Risk.

World Neurosurg 2018 Sep 5;117:e162-e166. Epub 2018 Jun 5.

Orthopedic Surgery Service, USC University Hospital Complex, Santiago de Compostela, Spain.

Background: To date, no information about the cortical bone microstructural properties in atlas vertebrae with arcuate foramen has been reported. As a result, we aimed to test in an experimental model if there is a cortical bone thickening in an atlas vertebra which has an arcuate foramen that may play a protective role against bone fracture.

Methods: We analyzed by means of micro-computed tomography the cortical bone thickness, the cortical volume, and the medullary volume (SkyScan 1172 Bruker micro-CT NV, Kontich, Belgium) in cadaveric dry atlas vertebrae with arcuate foramen and without arcuate foramen. We also reviewed a case series of 31 posterior atlas arch fractures to correlate the possible presence in the same atlas of both fracture and arcuate foramen.

Results: The micro-computed tomography study revealed significant differences in cortical bone thickness (P < 0.001), cortical volume (P < 0.004), and medullary volume (P = 0.013) values between the arcuate foramen vertebrae and the nonarcuate foramen vertebrae. The clinical series found no coexistence in the same vertebra of a posterior atlas arch fractures and the arcuate foramen.

Conclusions: An atlas with arcuate foramen presents cortical bone thickening. This advantage in bone microarchitecture seems to contribute to a lower fracture risk compared to subjects without arcuate foramen as no coexistence in the same vertebra of a posterior atlas arch fractures and arcuate foramen was found.
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http://dx.doi.org/10.1016/j.wneu.2018.05.220DOI Listing
September 2018

Can the transverse foramen/vertebral artery ratio of double transverse foramen subjects be a risk for vertebrobasilar transient ischemic attacks?

J Anat 2018 Jun 7. Epub 2018 Jun 7.

Department of Radiology, ERESA CT and MRI Unit, Valencia, Spain.

The C6 is the cervical vertebra into which the vertebral artery enters the passage of the transverse foramen and it is the vertebra most affected by double transverse foramina. There is currently little information about the relation between the vertebral artery and the double transverse foramen in C6. We aimed to test whether subjects with a double transverse foramen in C6 have a reduced transverse foramen/vertebral artery ratio when compared with normal anatomy subjects who possess a single transverse foramen which may be a risk for transient vertebral artery stenosis. We measured the area of the transverse foramen and the vertebral artery in 27 double transverse and 56 normal anatomy subjects using computed tomography angiography. We found significant differences in the area of the transverse foramen between double transverse and normal subjects (P < 0.001) but not between the vertebral artery area of double transverse and normal subjects (P = 0.829). The subjects with double transverse foramina have a reduced transverse foramen/vertebral artery ratio, which may be a possible risk for transient vertebral artery stenosis.
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http://dx.doi.org/10.1111/joa.12839DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6081508PMC
June 2018

Double Retrotransverse Foramen of Atlas (C1).

World Neurosurg 2018 Jun 20;114:e869-e872. Epub 2018 Mar 20.

Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, South Africa. Electronic address:

Background: The retrotransverse foramen is a nonmetric variant of C1 that consists of an abnormal accessory foramen on the posterior root of the transverse process.

Case Description: During a study on the prevalence of the retrotransverse foramen in 150 dry C1 vertebrae, we observed an exceptional C1 (0.67%) with a right double retrotransverse foramen of the 14 C1 vertebrae (9.3%). This has not been reported previously in the literature. No osteogenic reaction and no degenerative signs were observed in this C1 with the double retrotransverse foramen.

Conclusions: Neurosurgeons should be aware of the possible presence of the "conventional" retrotransverse foramen and the "exceptional" double retrotransverse foramen so that they can safely plan to prevent surgical complications. This will thus ensure better patient management by neurosurgeons.
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http://dx.doi.org/10.1016/j.wneu.2018.03.102DOI Listing
June 2018

The Decreasing Prevalence of the Arcuate Foramen.

World Neurosurg 2018 Feb;110:521-525

Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.

Background: The arcuate foramen (AF), or ponticulus posticus, is an anatomic variant of the first cervical vertebra that consists of a complete or partial osseous bridge over the groove for the vertebral artery and extends from the posterior aspect of the superior articular facet to the superior lateral border of the posterior arch. The AF has been associated with clinical symptoms, such as headache, migraine, neck pain, shoulder pain, arm pain, and vertebral artery dissection. We aimed to test whether the prevalence of the AF has decreased in the modern human population over the past centuries as a result of reduction in inbreeding and endogamy.

Methods: Possible reduction in the prevalence of the AF was assessed by comparing a 17th century rural sample (n = 108) with a 20th century modern urban sample (n = 192).

Results: When comparing the 17th and the 20th century samples, we found a statistically significant (P = 0.003) reduction of 14.5% (95% confidence interval 4.5-24.5) in the prevalence of the AF.

Conclusions: Prevalence of the AF has been decreasing over the past centuries.
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http://dx.doi.org/10.1016/j.wneu.2017.10.037DOI Listing
February 2018

Eco-geographic adaptations in the human ribcage throughout a 3D geometric morphometric approach.

Am J Phys Anthropol 2018 06 8;166(2):323-336. Epub 2018 Feb 8.

Paleoanthropology Group, Museo Nacional de Ciencias Naturales, Madrid, Spain.

Objectives: According to eco-geographic rules, humans from high latitude areas present larger and wider trunks than their low-latitude areas counterparts. This issue has been traditionally addressed on the pelvis but information on the thorax is largely lacking. We test whether ribcages are larger in individuals inhabiting high latitudes than in those from low latitudes and explored the correlation of rib size with latitude. We also test whether a common morphological pattern is exhibited in the thorax of different cold-adapted populations, contributing to their hypothetical widening of the trunk.

Materials And Methods: We used 3D geometric morphometrics to quantify rib morphology of three hypothetically cold-adapted populations, viz. Greenland (11 individuals), Alaskan Inuit (8 individuals) and people from Tierra del Fuego (8 individuals), in a comparative framework with European (Spain, Portugal and Austria; 24 individuals) and African populations (South African and sub-Saharan African; 20 individuals).

Results: Populations inhabiting high latitudes present longer ribs than individuals inhabiting areas closer to the equator, but a correlation (p < 0.05) between costal size and latitude is only found in ribs 7-11. Regarding shape, the only cold adapted population that was different from the non-cold-adapted populations were the Greenland Inuit, who presented ribs with less curvature and torsion.

Conclusions: Size results from the lower ribcage are consistent with the hypothesis of larger trunks in cold-adapted populations. The fact that only Greenland Inuit present a differential morphological pattern, linked to a widening of their ribcage, could be caused by differences in latitude. However, other factors such as genetic drift or specific cultural adaptations cannot be excluded and should be tested in future studies.
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http://dx.doi.org/10.1002/ajpa.23433DOI Listing
June 2018

Unexpected Persistent Dentocentral Synchondrosis of C2.

World Neurosurg 2018 Mar 15;111:26-27. Epub 2017 Dec 15.

Department of Anatomy and Human Embryology, Faculty of Medicine, University of Valencia, Valencia, Spain.

Background: The persistence of synchondrosis in adulthood can confound diagnostic decisions made during patient management.

Case Description: A 59-year-old woman who presented neck pain, acute headache, and acute cervical myelopathy symptoms after suffering whiplash grade 3 in a car rear-end impact underwent a conventional radiologic study that revealed no fracture and no anatomic spine variations. The magnetic resonance imaging study revealed no spinal cord intensity signal changes, but it showed a persistent (remnant) dentocentral synchondrosis that was undetected in a previous conventional radiographic evaluation.

Conclusions: The localization and level of the remnant of the dentocentral synchondrosis are extremely important from the clinical viewpoint because of odontoid and C2 fractures. Neurosurgeons should thus be aware of the possible presence of a persistent (remnant) C2 dentocentral synchondrosis in adult subjects in order to avoid misdiagnosis with C2 fracture.
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http://dx.doi.org/10.1016/j.wneu.2017.12.017DOI Listing
March 2018

Retrotransverse foramen of the atlas: prevalence and bony variations.

Eur Spine J 2018 06 7;27(6):1272-1277. Epub 2017 Nov 7.

Department of Human Anatomy and Physiology, Faculty of Health Sciences, University of Johannesburg, Johannesburg, South Africa.

Purpose: To analyze the prevalence of the retrotransverse foramen (RTF) and its bony variations.

Methods: One hundred ten atlases of living adult subjects, 161 twentieth century dry adult cervical atlases and four dry adult cervical atlases from medieval skeletons were studied to detect the RTF and its abnormal bony variations. The 110 living adult subjects underwent a computed tomography study to detect the RTF.

Results: In the in vivo sample (n = 110; 100%), the RTF was found in four (3.6%) atlases. It was bilateral in all cases, but three (2.7%) patients showed complete RTF and the other patient presented a complete RTF in the left transverse process and an unclosed RTF in the right transverse process. In addition, the RTF was observed in combination with an unclosed transverse foramen in two cases (1.8%). In the twentieth century skeletal sample (n = 206; 100%) the RTF was found in 15 (7.3%) C1 vertebrae. It was bilateral in three (1.5%) vertebrae and unilateral in another 12 (5.8%) vertebrae. In the medieval skeletal sample (n = 4; 100%) one cadaveric atlas (25%) presented a bilateral RTF with special bony characteristics which presented an unexpected spicula in the left RTF.

Conclusions: The RTF is a nonmetric variant of the atlas vertebra that can present non-degenerative and non-traumatic spiculae or it can be unclosed. In addition, it can be associated with the presence of unclosed transverse foramina.
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http://dx.doi.org/10.1007/s00586-017-5372-4DOI Listing
June 2018

The relationship between the distal metatarsal articular angle and intersesamoidal crista: An osteological study.

Foot (Edinb) 2017 Mar 17;30:5-12. Epub 2017 Jan 17.

Evolutionary Studies Institute, University of Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg, 2000, South Africa; School of Geosciences, University of Witwatersrand, 1 Jan Smuts Avenue, Braamfontein, Johannesburg, 2000, South Africa. Electronic address:

Background: As hallux valgus (HV) progresses, the first metatarsal drifts medially and the subsequent lateral drift of the sesamoids results in intersesamoidal crista erosion. This study aimed to provide a novel method of assessing crista erosion and determine if there is a relationship between that erosion and an increase in the distal metatarsal articular angle (DMAA).

Methods: The DMAA and size of the intersesamoidal crista was measured on the first metatarsals of 120 adult modern human individuals. There was an equitable spread of both sexes, a wide age range (18-88 years), from three South African population groups (Zulu, Sotho, "European"). The following non-metric features were observed: intersesamoidal crista appearance, metatarsal head shape, and first intermetatarsal facet. Correlation tests, t-tests and Analyses of Variance (ANOVA) were used to determine relationships between variables.

Results: The Pearson correlation test showed no significant correlation between the DMAA and crista ratio (r=0.092, p=0.154, α=0.05). DMAA: there was a significant difference between sides (p=0.009), right side larger; there was a significant difference between Zulu and "European" samples (p=0.036) but not between "Europeans" and Sotho (p=0.270); and there was a slight positive correlation with an increase in age. Crista: there was a significant difference between the sexes (p=0.044), with females having less erosion.

Conclusions: There is no significant relationship between the DMAA and crista erosion. Severe cartilaginous erosion is present before osteological changes occur, and the unexpected result may be reflected in skeletal specimens in which no cartilaginous changes can be observed. A novel, experimental method of assessing HV in modern human skeletal material is proposed.
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http://dx.doi.org/10.1016/j.foot.2017.01.006DOI Listing
March 2017

The vertebrae and ribs of Homo naledi.

J Hum Evol 2017 03 13;104:136-154. Epub 2017 Jan 13.

Evolutionary Studies Institute and Centre for Excellence in PalaeoSciences, University of the Witwatersrand, Private Bag 3, Wits 2050, South Africa.

Hominin evolution featured shifts from a trunk shape suitable for climbing and housing a large gut to a trunk adapted to bipedalism and higher quality diets. Our knowledge regarding the tempo, mode, and context in which these derived traits evolved has been limited, based largely on a small-bodied Australopithecus partial skeleton (A.L. 288-1; "Lucy") and a juvenile Homo erectus skeleton (KNM-WT 15000; "Turkana Boy"). Two recent discoveries, of a large-bodied Australopithecus afarensis (KSD-VP-1/1) and two Australopithecus sediba partial skeletons (MH1 and MH2), have added to our understanding of thorax evolution; however, little is known about thorax morphology in early Homo. Here we describe hominin vertebrae, ribs, and sternal remains from the Dinaledi chamber of the Rising Star cave system attributed to Homo naledi. Although the remains are highly fragmented, the best-preserved specimens-two lower thoracic vertebrae and a lower rib-were found in association and belong to a small-bodied individual. A second lower rib may belong to this individual as well. All four of these individual elements are amongst the smallest known in the hominin fossil record. H. naledi is characterized by robust, relatively uncurved lower ribs and a relatively large spinal canal. We expect that the recovery of additional material from Rising Star Cave will clarify the nature of these traits and shed light on H. naledi functional morphology and phylogeny.
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http://dx.doi.org/10.1016/j.jhevol.2016.11.003DOI Listing
March 2017

Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa.

Elife 2015 Sep 10;4. Epub 2015 Sep 10.

Evolutionary Studies Institute and Centre of Excellence in PalaeoSciences, University of the Witwatersrand, Johannesburg, South Africa.

Homo naledi is a previously-unknown species of extinct hominin discovered within the Dinaledi Chamber of the Rising Star cave system, Cradle of Humankind, South Africa. This species is characterized by body mass and stature similar to small-bodied human populations but a small endocranial volume similar to australopiths. Cranial morphology of H. naledi is unique, but most similar to early Homo species including Homo erectus, Homo habilis or Homo rudolfensis. While primitive, the dentition is generally small and simple in occlusal morphology. H. naledi has humanlike manipulatory adaptations of the hand and wrist. It also exhibits a humanlike foot and lower limb. These humanlike aspects are contrasted in the postcrania with a more primitive or australopith-like trunk, shoulder, pelvis and proximal femur. Representing at least 15 individuals with most skeletal elements repeated multiple times, this is the largest assemblage of a single species of hominins yet discovered in Africa.
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http://dx.doi.org/10.7554/eLife.09560DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4559886PMC
September 2015

Mosaic morphology in the thorax of Australopithecus sediba.

Science 2013 Apr;340(6129):1234598

Anthropological Institute and Museum, University of Zurich, Zurich, Switzerland.

The shape of the thorax of early hominins has been a point of contention for more than 30 years. Owing to the generally fragmentary nature of fossil hominin ribs, few specimens have been recovered that have rib remains complete enough to allow accurate reassembly of thoracic shape, thus leaving open the question of when the cylindrical-shaped chest of humans and their immediate ancestors evolved. The ribs of Australopithecus sediba exhibit a mediolaterally narrow, ape-like upper thoracic shape, which is unlike the broad upper thorax of Homo that has been related to the locomotor pattern of endurance walking and running. The lower thorax, however, appears less laterally flared than that of apes and more closely approximates the morphology found in humans.
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http://dx.doi.org/10.1126/science.1234598DOI Listing
April 2013