A saurischian (Archosauria, Dinosauria) ilium from the Upper Triassic of southern Brazil and the rise of Herrerasauria.

The Carnian (Upper Triassic) rocks of the Candelária Sequence present a rich record of dinosaurs, including some of the oldest known dinosaurs worldwide. In this contribution we describe the first unequivocal dinosaur from the Pivetta site, located in the Restinga Sêca municipality, Southern Brazil. The specimen CAPPA/UFSM 0373 is an isolated but well-preserved left ilium. A thorough examination of the specimen's anatomy and a phylogenetic analysis provides evidence that CAPPA/UFSM 0373 belongs to the Herrerasauria. We were able to identify several similarities with potential non-herrerasaurid herrerasaurians (e.g., Tawa hallae, "Caseosaurus crosbyensis"), which were previously only known from North American deposits. In contrast, herrerasaurids (e.g., Herrerasaurus ischigualastensis) are almost exclusively known from South America. Our results support the nesting of CAPPA/UFSM 0373 as an early-diverging herrerasaurian. Furthermore, this is potentially the first record of a non-herrerasaurid herrerasaurian in unambiguous Carnian beds, suggesting a hidden diversity of dinosaurs in the Carnian rocks of the Candelária Sequence, which can be revealed even by fragmentary specimens.

Transforaminal Endoscopic Approach to L5S1: Imaging Characterization of the Lower Lumbar Spine and Pelvis for Surgical Planning.

OBJECTIVE: To determine and compare pelvic and lumbosacral reference parameters with computed tomography in patients with low back pain (LBP) and a control group of asymptomatic patients to provide quantification data and morphological correlations for L5S1 transforaminal endoscopic approach (L5S1TEA). METHODS: We prospectively evaluated 100 patients with LBP and a control group of 100 individuals, with spinopelvic computed tomography. We measured lumbopelvic and L5S1 transforaminal approach parameters: maximum approach angle (maxAA) and minimum approach angle (minAA) and skin incision (maxSI and minSI), iliac crest (IC) projection at intersection point (ICPi), distance between the projected intersection of maxAA with the ilium (ICi) and the posterior limit of the IC (ΔICi-ICpost), and distance between ICi and spinous process (ΔICi-SP). RESULTS: Females and ICPi were increased in the LBP group: maxAA: 48.38° ± 5.09°; minAA:32.5° ± 3.90°; maxSI: 11.39 ± 1.86 cm; and minSI: 8.30 ± 1.48 cm. Ilium intersection was increased in males; IC projection at the highest point (ICPh) was higher than ICPi; maxAA intersected the ilium in 28% and minAA in 1.5% of cases; ICi was positively correlated with facet angle, ICPh, and ICPi and negatively with ΔICi-SP. CONCLUSIONS: Our results set preliminary reference values for L5S1TEA surgical planning. Besides higher ICPi, there were no differences between groups in measured parameters. Traditional IC height (ICPh) does not correspond to the point of intersection of the approach and is significantly higher than ICPi. ICi correlated to higher facet angle values, ICPh and ICPi grades, and lower ΔICi-SP. Potential conflict with the ilium is increased in the male population. IC is not impeditive of L5S1TEA in most cases.

Topographic localization of the sacroiliac joint and superior gluteal artery branches on the posterolateral ilium.

Latrogenic vascular injuries at the posterior ilium during sacroiliac screw placements are not uncommon. Though intra-operative imaging reduces the risk of such injuries, anatomical localization of the sacral segments using discrete topographical landmarks is not currently available. This descriptive study proposes the use of an anatomical grid system to localize the sacroiliac articulation on the posterolateral ilium. It also investigates the positional variability of the branches of the superior gluteal artery (SGA) within areas defined by the grid. 48 dried adult hip bones were examined to determine the position of the sacral articular surface on the posterolateral surface of the ilium. A novel grid-system was defined and used to map the positions of the articulation of the first two sacral segments on the posterolateral ilium. Superficial and deep branches of the SGA were dissected in donor cadavers and their courses were virtually overlayed on the grid system. The grid system localized the sacral articular surfaces within a defined area on the posterior ilium. Arterial distributions indicated the presence of the superficial branch of SGA more frequently over the screw insertion area (at an intermuscular plane), while the deep branch ran closer to the ilium but antero-inferior to the screw placement areas. This study proposes a new topographical perspective of visualizing SGA branches with respect to the cranial sacral segments. Precise localization of vascular anatomy may help to reduce potential risk of injury during sacroiliac screw placements.

Anatomy and morphology of iliolumbar ligament.

PURPOSE: To address limited amount of available data and contradictory statements in published works 60 Iliolumbar ligaments extracted from 30 cadavers were examined to describe their insertions and morphology. METHODS: The ligaments were removed during the standard autopsy procedures with a use of an oscillating saw, a chisel and a scalpel. The specimens were photographed before the extraction and measured alongside their anterior margin. Next, they were preserved in formaldehyde, stripped of other soft tissues and then examined, photographed and described. RESULTS: The mean length of the ligaments was 31.7 mm. 44 specimens were described as single-banded, 13 as double-banded and 3 as other. In 24 cases costal process of LV has been fixed to the iliac plate by short ligamentous bands. In 38 cases there was a thick fibrous membrane connected to the ligament. No legitimate insertions on LIV vertebra were observed. CONCLUSIONS: Typical iliolumbar ligament consists of a single ligamentous band. Most common variability of the ligament consist of two bands. In approximately 40% of cases the costal process of LV can be additionally stabilized to the iliac plate by short, strong ligamentous bands. In 63% of cases a connection between the iliolumbar ligament and a fibrous membrane placed in the frontal plane, superiorly to the ligament, has been observed. There seems to be no convincing proof of existence of the insertion of the iliolumbar ligament on the LIV vertebra.

Methods for sex estimation of prepubertal individuals (< 12 years old): bibliographic review and future directions.

Sex estimation is essential in both bioarchaeological and forensic research. Based on bibliographical research, this study aims to systematize and compare the existing methods and glance at the future on this research topic. The survey in Web of Science and Google Scholar revealed 37 papers describing the generation of original procedures, and 25 validation studies. The results show that the pelvis, namely the ilium, is the most analyzed anatomical region, followed by the deciduous teeth, the cranium, the mandible, and the long bones. The morphometric approaches are addressed in greater proportion, both as original methods (n = 19) or validations (n = 24). Only one of the 19 approaches that require expensive equipment (conventional radiology, computer tomography, geometric morphometrics and 3D modelling) was tested. Most of them were generated during the 21st century; however, 24 have not been tested yet. Comparing all the methods tested, the percentages of correctly estimated cases are always lower in validation studies. It is suggested that the most promising ones be tested in documented samples by a group of researchers. Thus, the interobserver error would be evaluated and may also lead to new methodological proposals and refinements.

Age-at-death estimation from the auricular surface of the ilium: A test of a sex-specific component method.

Accurate age-at-death estimation is important for both paleodemographic studies and forensic casework. Although the auricular surface of the ilium is a well-validated skeletal indicator for aging studies, problems persist with identifying features that estimate age accurately in older individuals. This study tests the utility of one method, developed by Igarashi et al. (2005), which claims to estimate age more accurately in older individuals using a presence/absence scoring system for 13 auricular surface traits. Four hundred (400) individuals, aged 16-93 years, from the Hamann-Todd Collection were examined to test the performance of Igarashi et al.'s method in a North American sample. Pearson's product-moment correlation tests were performed for both the overall method and individual traits to assess correlation with chronological age. Eleven of the 13 traits showed statically significant correlations with chronological age, and nine were found to have higher correlations than originally reported. The method showed a tendency toward negative bias (i.e., a tendency to under-age individuals, particularly in the older age range). Models for both males and females and full and reduced models developed by Igarashi et al. were tested; the sex-pooled full model performed best, and the female full model performed most poorly. Although this method did not have significantly higher accuracy rates in a North American sample than other auricular surface methods, unique traits identified by Igarashi et al. did correlate with chronological age. In future studies, these traits should be investigated using different scoring systems (e.g., character states), as they show utility for aging research.

Sex estimation of the subadult ilium prior to acetabular fusion.

Previous studies evaluating sexual dimorphism in subadult pelvic features present variable, and at times conflicting, conclusions. As a result, there is yet to be a consensus on whether the subadult pelvis can be used in sex estimation methods. This study aims to assess the forensic utility of ilium shape and greater sciatic notch morphology in sexing subadult pelves prior to acetabular fusion. A sample of 397 modern U.S. individuals with unfused acetabula (i.e., tri-radiate cartilages) aged birth to 14 years was queried from a larger sample of postmortem computed tomography scans. Elliptical Fourier analyses were performed on ilium and greater sciatic notch outlines and resultant PCs were evaluated for significant effects of sex and age. Greater sciatic notch metrics were also collected. Stepwise linear discriminant function analyses with leave-one-out cross-validation were performed on the PCs and metric variables. Analyses were performed on pooled samples, on age-specific cohort samples, and on samples that iteratively removed the youngest one-year cohort. Cross-validated correct classification rates ranged from 57% to 65% and no patterns were observed to support an appearance and/or consistent expression of sexually diagnostic traits. Based on the results, sex estimation using these features is not recommended in pelvic remains prior to acetabular fusion, although the sample sizes of individuals over 5 years of age were limited in this study. Future studies should focus on the sexually diagnostic ability of pelvic traits in subadult samples post-fusion of the acetabulum.

Analysis of the performance of machine learning and deep learning methods for sex estimation of infant individuals from the analysis of 2D images of the ilium.

Reducing the subjectivity of the methods used for biological profile estimation is, at present, a priority research line in forensic anthropology. To achieve this, artificial intelligence (AI) techniques can be a valuable tool yet to be exploited in this discipline. The goal of this study is to compare the effectiveness of different machine learning (ML) methods with the visual assessment of an expert to estimate the sex of infant skeletons from images of the ilium. Photographs of the ilium of 135 individuals, age between 5 months of gestation and 6 years, from the collection of identified infant skeletons of the University of Granada have been used, and classic ML and deep learning (DL) techniques have been applied to develop prediction algorithms. To assess their effectiveness, the results have been compared with those obtained by a forensic expert, who has estimated the sex from each photograph through direct observation and subjective assessment following the criteria described by Schutkowsky in 1993. The results show that the algorithms obtained using DL techniques offer an accuracy of 59%, very close to the 61% obtained by the expert, and 10 percentual points better than classic ML techniques. This study offers promising results and represents the first AI-based approach for estimating sex in infant individuals using photographs of the ilium.

Trabecular bone properties in the ilium of the Middle Paleolithic/Middle Stone Age Border Cave 3 Homo sapiens infant and the onset of independent gait.

The Border Cave 3 (BC3) infant skeleton has been understudied, despite its importance as an example of a well-preserved and fairly complete immature skeleton of early Homo sapiens which potentially provides a rare window into various aspects of ontogenetic development, including locomotor activity (e.g., timing of gait events). Trabecular structure in the BC3 ilium was evaluated to investigate whether it matches that of an equivalently aged infant from a postindustrialized society. Microcomputed tomography (µCT) scans were acquired from the BC3 infant and from an ontogenetic series of 25 postindustrial infants that were divided into three age classes (ACs) ranging from neonates to toddlers (<36 months). All ilia were qualitatively compared and then digitally subdivided into 10 volumes of interest (VOIs) based on anatomical reference points. The VOIs were quantified and ontogenetic differences in trabecular structure were statistically evaluated. Across the comparative ontogenetic series, trabecular architectural properties overlapped in all regions. However, trabecular thickness increased significantly after the first year of life. The BC3 infant demonstrated generally similar trabecular structure to that observed in the age-equivalent postindustrial infants (AC2), including relatively strong development of the trabecular chiasma qualitatively. However, some interesting distinctions were observed in BC3, such as low strut thickness compared with infants from the postindustrial sample, that bear further exploration in future studies. Evaluation of only one individual from the Middle Stone Age (MSA), coupled with the relatively small comparative sample, limit our ability to distinguish more meaningful biological differences in trabecular structure throughout ontogeny from idiosyncratic characteristics. Nonetheless, results of this study extend ongoing research on infant locomotor and morphological development to archeological populations in the Middle Stone Age. Further cross-cultural studies consisting of larger comparative postindustrial samples may provide additional information on trabecular structure in the infant ilium during this important developmental timeframe.

Effects of Surgical Positioning on L4-L5 Accessibility and Lumbar Lordosis in Lateral Transpsoas Lumbar Interbody Fusion: A Comparison of Prone and Lateral Decubitus in Asymptomatic Adults.

BACKGROUND: Lateral interbody fusion (LIF) is traditionally performed in lateral decubitus on a breaking surgical table to improve L4-L5 access. Prone transpsoas (PTP) LIF may improve sagittal alignment and facilitate single-position circumferential procedures; but may require manipulation of the iliac crest for L4-L5 accessibility. METHODS: Healthy adult volunteers (n = 41) were positioned as if for surgery in right-lateral decubitus on a radiolucent breaking table, and also prone on a Jackson-style surgical frame atop a custom PTP bolster. Iliac crest distance from the L5 superior endplate, and coronal and sagittal plane alignments were measured from fluororadiographs obtained in each of 5 positions: standard lateral decubitus (LD), prone-hips and spine neutral (PR-NN), prone-hips neutral and spine coronally bent (PR-NCB), prone-hips extended and spine neutral (PR-EN), and prone-hips extended and spine coronally bent (PR-ECB). RESULTS: L4-L5 accessibility was lowest in prone-neutral and improved in all augmented positional configurations: PR-NN<>PR-ENLD, P = 0.0480). Coronal angulations were greatest in LD, and statistically different from both prone neutral (LD>PR-NN, P < 0.0001) and prone coronally bent (LD>PR-NCB, P < 0.0001). Lordosis was greatest in extended prone positions and lowest in lateral decubitus: PR-EN>PR-ECB>PR-NCB<>PR-NN>LD. All prone positions showed significantly greater lordosis than lateral decubitus (P < 0.001). CONCLUSIONS: Compared with lateral decubitus, prone positioning provides equivalent or better L4-L5 LIF access around the iliac crest when a positioner is used that enables coronal bending, and improved positional lordosis, which may facilitate segmental correction and achievement of surgical alignment goals.

Evaluation of the auricular surface method for subadult sex estimation on Italian modern (19th to 20th century) identified skeletal collections.

OBJECTIVES: Sex estimation in subadult skeletal remains is still considered highly problematic. The aim of this research is to test the reliability of the method of subadult sex assessment proposed by Luna and co-workers in 2017, based on the analysis of the auricular surface of the ilium. MATERIALS AND METHODS: Seven ratios and three morphological traits were recorded for 127 subadult individuals (63 males and 64 females), aged between 0 and 17 years, from several Identified Skeletal Collections of the University of Bologna. Nonparametric Mann Whitney test, Kolmogorov Smirnov test, and the Pearson correlation coefficient were used for continuous variables, whereas the Cramer Coefficient was calculated for qualitative variable. A principal component analysis was also performed on ratio values. The statistic ƞ was taken into account for both types of variables. RESULTS: None of the ratios presented significant dimorphic results. Two qualitative variables show statistically significant differences between sexes. The overall morphology proved to be an accurate sex predictor among children aged ≥4 years (78%-86%) and meets the minimum accuracy standard (75%) for subadult sex estimation for individuals between 1 and 17 years of age. The morphology of the retroauricular end of the superior demiface (MRS) can be used with a high level of accuracy for sexing individuals from 1 to 12 years (77%-81%). CONCLUSIONS: The metric variables did not replicate the accuracy values originally obtained by Luna and co-workers. Otherwise, the evaluation of the morphological variables proposed by the authors yielded promising results as a reliable sexing technique for individuals who died before puberty.

Test of the auricular surface sex estimation method in fetuses and non-adults under 5 years old from the Lisbon and Granada Reference Collections.

Non-adult sex estimation is an active field of forensic inquiry as morphological variations between males and females are subtle, but observable, even from intrauterine development. The objectives of this study are threefold: to test the validity of the auricular surface method for sex estimation (Int J Osteoarchaeol 27:898-911, 2017) in fetuses and children under the age of 5 years old; to evaluate if health conditions, reported as the cause of death, influence its accuracy; and to detect possible secular trends in sexual dimorphism. One-hundred and ninety-seven skeletal individuals from the Lisbon and Granada Identified Collections were studied. Individuals were divided according to the hormonal peaks (< 0, 0-2, < 2, and 2.1-5 years old), cause, and year of death (before and after 1960). As in previous studies, two ratios (FI/CF and DE/AD) and two qualitative variables (OM and MRS) showed the highest frequencies of correct estimation (0.81-0.86). The correct sex allocations increased when the discriminant function (0.85) and logistic regression (0.86) were applied. Males of the age groups < 0 and 2.1-5 years were all correctly sexed by both formulae, and the same was observed for the female probabilities of adequate allocation. The cause and year of death were identified as variables without statistical significance. It is proposed that this method can be incorporated with confidence into the multifactorial laboratory protocols for non-adult sex estimation from skeletal remains.

Preoperative Simulation of the Trajectory for L5/S1 Percutaneous Endoscopic Transforaminal Discectomy: A Novel Approach for Decision-Making.

OBJECTIVE: We simulated the trajectory for an L5/S1 percutaneous endoscopic transforaminal discectomy (PETD) to guide decision-making for the surgery approach. METHODS: Twenty-three patients with L5/S1 lumbar disc herniation were included in the study. The patients all underwent thin-section computed tomography scans, after which data were collected for 3-dimensional reconstruction. Simulations of the trajectory for the L5/S1 PETDs were generated and the hindrance of surrounding anatomic structures was evaluated. RESULTS: Preoperative simulation showed that 14 patients were considered suitable for lumbar PETD. Nine patients were not considered suitable for PETD surgery according to the simulation. Factors affecting the trajectory included high iliac crest in 5 patients, L5 transverse process in 3 patients, and hypertrophic L5-S1 facet joint in 1 patient. CONCLUSIONS: Preoperative simulation of the trajectory for L5/S1 PETD was helpful in the decision-making for the surgical approach.

An evaluation of statistical models for age estimation and the assessment of the 18-year threshold using conventional pelvic radiographs.

The developmental patterns of the pelvic epiphyses are one of the anatomical markers used in the assessment of skeletal age and the legally relevant age threshold. In this study, four regression models and five classification models were developed for forensic age estimation and the determination of the 18-year threshold, respectively. A total of 2137 conventional pelvic radiographs (1215 males and 922 females) aged 10.00-25.99 years were analyzed, and the ossification and fusion of the iliac crest and ischial tuberosity epiphyses were scored separately. The epiphyses on both sides were used as inputs for all models. The accuracy of the regression models was compared using the mean absolute error (MAE) and root mean square error. The percentages of correct classifications were evaluated for the determination of the 18-year threshold. Support vector regression (SVR) and gradient boosting regression (GBR) showed higher accuracy for age estimation in both sexes. The lowest MAE was 1.38 years in males when using SVR and 1.16 years in females when using GBR. In the demarcation of minors and adults, the percentage of correct classification was over 92%, and the area under the receiver operating characteristic curves was over 0.91 in all models, except the Bernoulli naive Bayes classifier. This study demonstrated that the present models may be helpful for age estimation and the determination of the 18-year threshold. However, owing to the high effective dose of ionizing radiation used during conventional radiography of the pelvis, it is expected that these models will be tested with pelvic MRI for age estimation.

Anatomical conditions and patient-specific locked navigation templates for transverse sacroiliac screw placement: a retrospective study.

OBJECTIVE: To analyse the anatomical conditions of transverse sacroiliac screw (TSS) about the S1 and S2 segments in order to develop and validate a locked navigational template for TSS placement. METHODS: A total of 22 patients with sacral fractures were involved in this study from May 2018 to February 2019. Patients were divided into two groups according to the surgery procedure: locked template group and conventional group. The CT data of 90 normal sacra were analysed. The long axis, short axis and lengths of TSS, cancellous corridors were measured through 3D modelling. A patient-specific locked navigation template based on simulated screws was designed and 3D printed and then used to assist in TSS placement. The operative time and radiation times were recorded. The Matta criteria and grading score were evaluated. The entry point deviation of the actual screw placement relative to the simulated screw placement was measured, and whether the whole screw was in the cancellous corridor was ob`served. RESULTS: S1 screws with a diameter of 7.3 mm could be inserted into 69 pelvises, and S2 screws could be inserted in all pelvises. The S1 cancellous corridor had a long axis of 25.44 ± 3.32 mm in males and 22.91 ± 2.46 mm in females, a short axis of 14.21 ± 2.19 mm in males and 12.15 ± 3.22 mm in females, a corridor length of 153.07 ± 11.99 mm in males and 151.11 ± 8.73 mm in females, and a proportional position of the optimal entry point in the long axis of the cancellous corridor of 35.96 ± 10.31% in males and 33.28 ± 7.2% in females. There were significant differences in the corridor long axis and corridor short axis between sexes (p < 0.05), and there were no significant differences in corridor length and proportional position of the optimal entry point in the long axis of the cancellous corridor between sexes (p > 0.05). The S2 cancellous corridor had a long axis of 17.58 ± 2.36 mm in males and 16 ± 2.64 mm in females, a short axis of 14.21 ± 2.19 mm in males and 13.14 ± 2.2 mm in females, a corridor length of 129.95 ± 0.89 mm in males and 136.5 ± 7.96 mm in females, and a proportional position of the optimal entry point in the long axis of the cancellous corridor of 46.77 ± 9.02% in males and 42.25 ± 11.95% in females. There were significant differences in the long axis, short axis and corridor length (p < 0.05). There was no significant difference in the proportional position of the optimal entry point in the long axis of the cancellous corridor (p > 0.05). A total of 20 transversal sacroiliac screws were successfully implanted into 10 patients with the assistance of locked navigation templates, and a total of 24 transversal sacroiliac screws were successfully implanted into 12 patients under C-arm fluoroscopy. There was a significant difference in surgical time (88 ± 14.76 min vs 102.5 ± 17.12 min, p = 0.048), radiation times (11.5 ± 1.78 vs 54.83 ± 6.59, p < 0.05) and screw grading between two groups (nineteen screws in grade 0, one screw in grade 1 and 0 screws in grade 2 vs fourteen screws in grade 0, 8 screws in grade 1 and 2 screws in grade 2, p = 0.005). All screw entry point deviations were shorter than the short axis of the cancellous corridor, and all screws were located completely within the cancellous corridor. CONCLUSION: Approximately 76% of males and females can accommodate screws with diameters of 7.3 mm in S1, and all persons can accommodate the same screw in S2. From the standard lateral perspective of the sacrum, the optimal entry point of the transverse screw is in the first 1/3 of the cancellous corridor for S1 and the centre of the cancellous corridor for S2. The patient-specific locked navigation template assisted in TSS placement with less operative time, less intraoperative fluoroscopy and higher safety of screw placement compared with traditional surgery.

The influence of musculoskeletal forces on the growth of the prenatal cortex in the ilium: a finite element study.

Remodelling and adaptation of bone within the pelvis is believed to be influenced by the mechanical strains generated during locomotion. Variation in the cortical bone thickness observed in the prenatal ilium has been linked to the musculoskeletal loading associated with in utero movements; for example the development of a thicker gluteal cortex is a possible response to contractions of the gluteal muscles. This study examines if the strains generated in the prenatal iliac cortex due to musculoskeletal loading in utero are capable of initiating bone remodelling to either maintain homeostasis or form new bone. Computational modelling techniques were used firstly to predict the muscle forces and resultant joint reaction force acting on the pelvis during a range of in utero movements. Finite element analyses were subsequently performed to calculate the von Mises strains induced in the prenatal ilium. The results demonstrated that strains generated in the iliac cortex were above the thresholds suggested to regulate bone remodelling to either maintain homeostasis or form new bone. Further simulations are required to investigate the extent to which the heterogeneous cortex forms in response to these strains (i.e., remodelling) or if developmental bone modelling plays a more pivotal role.

Fibrous configuration of the fascia iliaca compartment: An epoxy sheet plastination and confocal microscopy study.

BACKGROUND AND OBJECTIVES: The underlying anatomical mechanism of the ultrasound-guided fascia iliaca compartment (FIC) block for anaesthesia and analgesia in the lower limb has not been illuminated and numerous variations were attempted to achieve an optimal needle placement. This study aimed to define the fibrous configuration of the FIC. METHODS: A total of 46 adult cadavers were studied using dissection, latex injection, epoxy sheet plastination and confocal microscopy. RESULTS: (1) The fascia iliaca originated from the peripheral fascicular aponeurotic sheet of the iliopsoas. (2) The FIC was a funnel-shaped adipose space between the fascia iliaca and the epimysium of the iliopsoas, had a superior and an inferior opening and contained the femoral and lateral femoral cutaneous nerves but not obturator nerve. (3) The estimated volume of the FIC in the cadavers was about 23 mls, of which about one third was below the level of the anterior superior iliac spine. CONCLUSIONS: This study revealed that the fascia iliaca was aponeurotic and may be less permeable for the local anesthetics. CONCLUSIONS: The FIC contained only the femoral and lateral femoral cutaneous nerves and communicated with the extraperitoneal space and femoral triangle adipose space via its superior and inferior opening, respectively.

Evaluation of the auricular surface method for non-adult sex estimation on the Lisbon documented collection.

OBJECTIVES: Sex is usually not estimated in skeletonized non-adult individuals because sexual dimorphism is considered minimal before puberty. In 2017, a new approach based on the shape of the auricular surface was proposed, showing that this anatomic area of the ilium is dimorphic. This study tests the reproducibility and evaluates the accuracy of the method in a bigger sample. MATERIALS AND METHODS: Thirty males and 31 females from the Lisbon Collection (1 day-18 years old) were analyzed by two researchers, one experienced, and the other without previous knowledge of the method. The sample was divided into three groups according to prepubertal and pubertal hormonal peaks (<2, 0-12, and 13-18 years old). Two metric variables (DE/AD and FI/CF ratios), two morphological features (Overall Morphology, OM and Morphology of the Retroauricular End of the Superior Demiface, MRS), and two formulae were tested based on the adequate results obtained in the original article. RESULTS: Data shows a low interobserver error (ICC > 0.92; K > 0.74). Morphological features provide better results than the metrics (DE/AD = 77.05%; FI/CF = 73.77%; OM = 80.33%; MRS = 85.24%). The discriminant function correctly classified 86.66% of the males and the logistic regression, 83.33%. The method was equally reliable in 0-12 and 13-18 years-old age groups and more accurate in males. The accuracy of most of the variables reached 100% for males under 2 years-old, and the probabilities were higher than for older individuals. The percentages of correct estimations are not influenced by the age, year, and cause of death. DISCUSSION: Despite the relatively small sample size, this study confirms the usefulness of the auricular surface for non-adult sexual estimation, especially for those younger than 2 years old. Additional validation tests in documented individuals from other geographic regions are suggested.

The iliosacral joint in lizards: an osteological and histological analysis.

The development of the iliosacral joint (ISJ) in tetrapods represented a crucial step in the evolution of terrestrial locomotion. This structure is responsible for transferring forces between the vertebral column and appendicular skeleton, thus supporting the bodyweight on land. However, most research dealing with the water-to-land transition and biomechanical studies in general has focused exclusively on the articulation between the pelvic girdle and femur. Our knowledge about the contact between the pelvic girdle and vertebral column (i.e. the ISJ) at a tissue level is restricted so far to human anatomy, with little to no information available on other tetrapods. This lack of data limits our understanding of the development and evolution of such a key structure, and thus on the pattern and processes of the evolution of terrestrial locomotion. Therefore, we investigated the macro- and microanatomy of the ISJ in limb-bearing squamates that, similar to most non-mammalian, non-avian tetrapods, possess only two sacral ribs articulating with the posterior process of the ilium. Using a combination of osteology, micro-computed tomography and histology, we collected data on the ISJ apparatus of numerous specimens, sampling different taxa and different ontogenetic stages. Osteologically, we recorded consistent variability in all three processes of the ilium (preacetabular, supracetabular and posterior) and sacral ribs that correlate with posture and locomotion. The presence of a cavity between the ilium and sacral ribs, abundant articular cartilage and fibrocartilage, and a surrounding membrane of dense fibrous connective tissue allowed us to define this contact as a synovial joint. By comparison, the two sacral ribs are connected to each other mostly by dense fibrous tissue, with some cartilage found more distally along the margins of the two ribs, defining this joint as a combination of a syndesmosis and synchondrosis. Considering the intermediary position of the ISJ between the axial and appendicular skeletons, the shape of the articular surfaces of the sacral ribs and ilium, and the characteristics of the muscles associated with this structure, we argue that the mobility of the ISJ is primarily driven by the movements of the hindlimb during locomotion. We hypothesize that limited torsion of the ilium at the ISJ happens when the hip is abducted, and the joint is likely able to absorb the compressional and extensional forces related to the protraction and retraction of the femur. The mix of fibres and cartilage between the two sacral ribs instead serves primarily as a shock absorber, with the potential for limited vertical translation during locomotion.

The Modified Iliac Screw: An Anatomic Comparison and Technical Guide.

BACKGROUND: Iliac screws are a widely used sacropelvic fixation technique, which is often criticized for its impaired wound healing owing to hardware prominence. The aim of this study was to present a modified iliac screw (MIS) fixation technique that uses a different entry point more medially and caudally to the posterior superior iliac spine next to the rudimentary S1-S2 joint. Soft tissue coverage and midline distance in an MIS and a traditional iliac screw were compared. METHODS: Two different variations of iliac screws were placed into 12 fresh frozen adult cadavers (9 male, 3 female, mean age at death 77.08 years, mean body mass index 23.4). The distance between the midline and the center of the screw head was measured. We also compared the angulation of the trajectories. After wound closure, we measured the distance between the iliac screw head and the skin. RESULTS: The mean distance from the screw tulip head to the skin was 2.43 cm (range, 1.2-4.2 cm) with the traditional iliac screw and 3.16 cm (range, 1.7-4.3 cm) with the MIS. The mean distance to the midline with the MIS was 3.1 cm (range, 2.4-4.5 cm) lateral to the midline compared with the traditional iliac screw, of which the mean was 4.2 cm lateral to the midline (range, 3.7-4.9 cm). Mean angulation was 10°. CONCLUSIONS: The MIS avoids the use of connectors and provides less prominent pelvic fixation. Clinically, this might help prevent prominent hardware and related wound healing impairment.