Journal of Anatomy

The supracondylar foramen with a seemingly osseous peripheral arch noticed on the medio-distal feline humeri had remained disputed among anatomists. Some scholars have argued in favor of homology between this foramen and the supracondyloid foramen formed in the presence of the ligament of Struthers in humans. Other theories include its presence as a retinaculum holding the median nerve and brachial artery to their anatomical position in a flexed elbow. Unfortunately, these theories lack investigative rigor. The emergence of non-invasive imaging modalities, such as micro-computed tomography, has enabled researchers to inspect the internal anatomy of bones without dismantling. Thus, a micro-computed tomographic investigation was conducted on three feline humeri specimens while the internal anatomy of the supracondylar foramina was examined. Unlike the humerus, the thin peripheral arch of the feline supracondylar foramen failed to elicit any osseous trabeculae or foci of calcification. While adhering to the humeral periosteum at its origin, the non-osseous arch, typical of a muscular tendon or a ligament, inserts into a bony spur attached to the medial humeral epicondyle suggestive of a ligament or aponeurotic extension of a (vestigial) brachial muscle, with the coracobrachialis longus emerging to be the most likely candidate.

Osteoderms are bony plates which develop in the dermis of the skin of vertebrates, most commonly found in fishes and reptiles. They have evolved independently at least eight times in reptiles suggesting the presence of a gene regulatory network which is readily activated and inactivated. The absence of osteoderms in birds and mammals, except for the one example of armadillos, has prevented a comparative molecular approach to their evolution. However, following CT scanning, we have discovered that in two genera of Deomyinae, the spiny mouse Acomys and the brush-furred mouse, Lophuromys there are osteoderms present in the skin of their tails. We have studied osteoderm development within the dermis of the tail in Acomys cahirinus to show that they begin development before birth in the proximal part of the tail skin and they do not complete differentiation throughout the tail until 6 weeks after birth. This has allowed us to study the cellular differentiation of the osteoderms with histology and immunocytochemistry and perform RNA sequencing to identify the gene networks involved in their differentiation. There is a widespread down-regulation of keratin genes and an up-regulation of osteoblast genes and a finely balanced expression of signaling pathways as the osteoderms differentiate. Future comparisons with reptilian osteoderms may allow us to understand how these structures have evolved, why they are so rare in mammals and how they are position-specific.

Spider morph ball pythons are a frequently bred design morph with striking alterations of the skin color pattern. We created high resolution {micro}CT-image series through the otical region of the skulls, used 3D-reconstruction software for rendering anatomical models, and compare the anatomy of the semicircular ducts, sacculus and ampullae of wildtype Python regius (ball python) with spider morph snakes. All spider morph snakes showed the wobble condition. We describe the inner ear structures in wild-type and spider-morph snakes and report a deviant morphology of semicircular canals, ampullae and sacculus in spider morph snakes. We also report about associated differences in the desmal skull bones of spider morph snakes. The spider morph snakes were characterized by wider semicircular canals, anatomically poorly defined ampulla, a deformed crus communis and a small sacculus, with a highly deviant x-ray morphology as compared to wildtype individuals. We observed considerable intra- and interindividual variability of these features. This deviant morphology of spider morph snakes can easily be associated with an impairment of sense of equilibrium and the observed neurological wobble condition. Limitations in sample size prevent statistical analyses, but the anatomical evidence is strong enough to support an association between the wobble condition in design bread spider morph snakes and a malformation of the inner ear structures. A link between artificially selected alterations in pattern and specific color design with neural-crest associated developmental malformations of the statoacoustic organ as known from other vertebrates is discussed.

AIMTo analyze the increase in the cross-sectional area (CSA) of the median nerve during early childhood. METHODThis prospective, cross-sectional study used high-resolution ultrasound images of the median nerve from three locations (wrist, forearm and upper arm). A total of 43 participants (32 of whom were children younger than 2 years) were included in the study. RESULTSA strong and highly significant correlation was found between age and CSA (r = 0.8, p < 0.0001). The growth rate of CSA decreases with age. The increase in CSA follows a logarithmic growth curve (p < 0.0001). Based on the regression analysis, an age-synchronous increase in CSA for all three locations was found. The nerve reaches 70% of its final CSA by 2 years of age. INTERPRETATIONSimilar to the nerve conduction speed, the increase in CSA is greatest during the first 2 years of life. Then, the rate gradually and synchronously slows at the proximal and distal locations. What this paper adds- Normative values for increased cross-sectional area (CSA) of the median nerve. - Standardized locations and image procedures outlined for the clinical setting. - Growth dynamic of the CSA of the median nerve in children. - Normative data for development of the median nerve in children. - High resolution ultrasound images of the maturating median nerve in neonates, infants and children.

Individuals with complex congenital heart disease (CHD) are at increased risk for cognitive impairments linked to altered brain structure, including reduced cortical volume. Cortical volume is determined by two distinct morphometric measures: cortical thickness (CT) and surface area (SA), each with unique developmental, genetic, and evolutionary origins. Despite their importance, few studies have examined the differential contributions of CT and SA to cortical volume alterations and cognitive outcomes in CHD. Exploring these individual cortical morphometric changes may provide additional insight into the origin of cortical volume changes in CHD, and their relationships with cognitive function. High-resolution 3D T1-weighted images, IQ and executive function (EF) scores were acquired from a final sample of 49 patients with CHD and 80 controls (mean age=13.16, male:54.3%). Cortical reconstruction and volumetric analyses were performed using Freesurfer version 7.1. Group differences in cortical volume, CT, and SA, as well as their associations with cognitive measures, were investigated through vertex-wise multivariate general linear modelling. While both SA and CT were significantly reduced in the CHD group, both globally and regionally, SA was more affected than CT, and total SA showed a stronger and more consistent correlation with cortical volume. Furthermore, SA, but not CT, was strongly associated with IQ and EF across the brain. These relationships were especially prominent in the frontal and occipitotemporal cortices, where patients with CHD exhibited stronger associations between SA and cognitive performance compared to controls. These findings indicate that cortical volume reductions observed in CHD primarily reflect reduced cortical surface area rather than cortical thinning. While structure-function associations between cortical morphology and cognition are established in healthy populations, our data suggest that these relationships are accentuated in CHD, likely due to disrupted neurodevelopmental processes. This study underscores the importance of differentiating cortical morphometric features to improve our understanding of brain-behaviour associations and the neurobiological underpinnings of cognitive impairment in CHD.ss

In the course of performing a detailed dissection of adult rat to map the cutaneous nerves of cervical, thoracic, and lumbar levels a small and unexpected structure was isolated. It appeared to be a cutaneous striated muscle and was observed in both male and female rats and in mice but absent from cats and humans. With the skin reflected laterally from midline, the muscle lies closely apposed to the lateral border of the Thoracic Trapezius (Spinotrapezius) muscle and is easily missed in standard gross dissections. Focussed prosections were performed to identify the origin, insertion, and course of gross innervation. Identification of each of these elements showed them to be distinct from the nearby Trapezius and Cutaneous Trunci (Cutaneous Maximus in mouse) muscles. The striated muscle nature of the structure was validated with whole-mount microscopy.Consulting a range of published rodent anatomical atlases and gross anatomical experts revealed no prior descriptions. This preliminary report is an opportunity for the anatomical and research communities to provide input to either confirm the novelty of this muscle or refer to prior published descriptions in rodents or other species while the muscle, its innervation, and function are further characterized. Presuming this muscle is indeed novel, the name "Cutaneous Scapularis muscle" is proposed in accord with general principles of the anatomical field.

There is general awareness of artificial selection and its potential implications on health and welfare of animals. Despite growing popularity and increasing numbers of breeds of atypical colour and pattern variants in reptiles, only few studies have investigated the appearance and cause of various diseases associated with colour morphs. Ball pythons (Python regius) are among the most frequently bred reptiles and breeders selected for a multitude of different colour and pattern morphs. Among those colour variants, the spider morph of the ball python is frequently associated with the wobble syndrome. The aim of this study was to determine, whether a morphological variant can be found and brought in association with the clinical occurrence of the wobble syndrome in spider ball pythons, using MRI and CT-imaging as intra-vitam diagnostic methods. Data from eight ball pythons including five spider ball pythons and three wild type ball pythons was assessed and evaluated comparatively. We were able to identify distinctive structural differences in inner ear morphology in spider ball pythons highly probable to relate to the wobble syndrome. To our knowledge, these anomalies are described for the first time and represent a basis for further anatomical and genetic studies and discussions regarding animal welfare in reptile breeding.

Background. Brain development is altered in neonates with congenital heart disease (CHD). However, development in the perioperative period remains incompletely understood. Purpose. This study used Structural Covariance Component (SCC) analysis to identify brain regions showing spatial patterns of coordinated expansion and contraction that differ between neonates with CHD after cardiac intervention and healthy controls, as well as pre-to postoperative changes and effects of perioperative risk factors. Study type. Prospective. Population. The cohort included 41 neonates with CHD who underwent cardiac surgery or catheterization and 359 healthy neonates. Field strength and sequence. 3 Tesla T2-weighted turbo-spin-echo sequence. Assessment: Brain MRI were motion-corrected and reconstructed using an established neonatal algorithm. Jacobian determinants calculated from non-linear registration of MRI to a neonatal template were input into an Independent Component Analysis to identify SCCs (N=40). SCC weightings were extracted, reflecting the degree to which the pattern of covariance is expressed in each neonate. Statistical tests. Postoperative SCC weightings were compared to healthy neonates using a general linear model or robust regression. Pre- and postoperative SCC weightings were compared using a linear mixed effect model. Pre- to postoperative differences were calculated and associations with age at surgery, cardiopulmonary bypass duration, and postoperative paediatric intensive care unit stay were assessed using partial spearman's rank correlation. Analyses were adjusted for covariates and corrected for multiple comparisons using False Discovery Rate. Results. 16/40 SCCs showed significant differences between neonates with CHD after surgery and controls, including white matter, cortical- and deep grey matter, brainstem, and CSF regions, with seven also showing significant perioperative change. A further nine SCCs only showed significant perioperative change. Perioperative risk factors were not associated with perioperative change. Data conclusion. This data-driven approach highlights region-specific postoperative alterations and perioperative changes in brain morphology of neonates with CHD. Evidence level. 1. Technical Efficacy. Stage 3.

ObjectivesThe intricate trabecular architecture of long-bone epiphyses underpins functional adaptations for diverse mammalian locomotion. Despite extensive study in other mammals, tamarin trabecular structure and fine-grained differences among leaping taxa remain poorly characterized. Materials and MethodsWe examined humeral and tibial trabecular networks in four tamarin species representing short- and long-distance leapers using {micro}CT-scans and a whole-epiphysis approach. We quantified network complexity with topological indices (node density, tortuosity, trabecular length, fractal dimension) alongside traditional metrics (degree of anisotropy [DA], bone volume fraction [BV/TV]) to capture both geometric and topological features. ResultsLong leapers exhibit significantly higher node density in both humeral and tibial epiphyses and increased trabecular tortuosity in the distal humerus. Elevated node density localizes beneath the humero-scapular joint, within the proximal humerus, and in variable regions across other epiphyses. Other parameters (DA, BV/TV, trabecular length, fractal dimension) showed no leaping-related differences, instead correlating with sex and captivity. DiscussionIncreased mechanical strain during longer leaps likely drives higher node density and, to a lesser extent, tortuosity in humeral and tibial epiphyses, with node density showing the strongest functional signal. While sex and captivity influence other trabecular traits, patterns in these key metrics support locomotor adaptation. Integrating whole-epiphysis analyses with novel topological indices enhances detection of subtle functional signals and complements VOI-based and traditional frameworks in comparative trabecular bone studies.

The anatomical description of the hourglass dolphin (Lagenorhynchus cruciger) and the spectacled porpoise (Phocoena dioptrica) remains largely unexplored, due to limited specimen availability and preservation challenges. This study employed digital imaging techniques, conventional histology and computed tomography to provide visualisation of anatomical structures for a detailed analysis. We present a comprehensive analysis of the gross macroscopical and microscopical morphology of two hourglass dolphins and four spectacled porpoises. The hourglass dolphins were characterised by their distinctive black and white pigmentation and a hooked dorsal fin, while the spectacled porpoises were defined by their large dorsal fin, lack of a visible rostrum and unique eye markings. Morphometric measurements and skeletal characteristics aligned with the literature, while internal anatomy (organs and systems) were similar to other odontocetes. Although precise lung measurements were challenging, qualitative assessments indicated relatively large lungs for their body size, supporting the "short dive, big lung" hypothesis and suggesting that these species are not deep divers. The spectacled porpoise dorsal fin was uniquely large with a well-developed blood supply; this is hypothesised to act as a thermoregulatory window, helping to manage body heat. Overall, this study provides new data on the anatomy of the hourglass dolphin and spectacled porpoise, contributing insights that may influence future research on these rare species. The findings highlight the importance of anatomical studies in explaining evolutionary relationships within cetaceans and their ecological roles in the Southern Ocean ecosystems.

Unique cardiovascular adaptations in giraffes (Giraffa Camelopardalis reticulata) have been the focus of numerous investigations for almost a century. The vertical distance between the heart and brain impose high pressure on the giraffe left ventricle leading to thickening that exceeds heart in other mammals. Yet, cardiovascular function appears to be unimpacted by these morphologic differences. Physiologically adapted atrioventricular conduction may contribute to these unique cardiovascular characteristics. Atrioventricular (AV) function was assessed to determine whether physiologically adapted AV intervals might optimize the delay between atrial and ventricular contractions. Using ambulatory and intracardiac recordings, we report a longer PR interval in giraffes than predicted by allometric scaling. Slow ventricular response during atrial fibrillation further supports species-specific atrioventricular adaptations.

Synovial joints, characterized by reciprocally congruent and lubricated articular surfaces separated by a cavity, are hypothesized to have evolved from continuous cartilaginous joints for increased mobility and improved load bearing. To test the evolutionary origins of synovial joints, we examine the morphology, genetic, and molecular mechanisms required for the development and function of the joints in elasmobranchs and cyclostomes. We find the presence of cavitated and articulated joints in elasmobranchs, such as the little skate (Leucoraja erinacea) and bamboo shark (Chiloscyllium plagiosum), and the expression of lubrication-related proteoglycans such as aggrecan and glycoproteins such as hyaluronic acid receptor (CD44) at the articular surfaces in little skates. Sea lampreys (Petromyozon marinus), a representative of cyclostomes, are devoid of articular cavities but express proteoglycan-linking proteins throughout their cartilaginous skeleton, suggesting that the expression of proteoglycans is primitively not limited to the articular cartilage. Analysis of the development of joints in the little skate reveals the expression of growth differentiation factor-5 (Gdf5) and {beta}-catenin at the joint interzone before the process of cavitation, indicating the involvement of BMP and Wnt-signaling pathway, and reliance on muscle contraction for the process of joint cavitation, similar to tetrapods. In conclusion, our results show that synovial joints are present in elasmobranchs but not cyclostomes, and therefore, synovial joints originated in the common ancestor of extant gnathostomes. A review of fossils from the extinct clades along the gnathostome stem further shows that synovial joints likely arose in the common ancestor of gnathostomes. Our results have implications for understanding how the evolution of synovial joints around 400 mya in our vertebrate ancestors unlocked motor behaviors such as feeding and locomotion. Author summaryWe owe our mobility and agility to synovial joints, characterized by a lubricated joint cavity between the bony elements. Due to the cavity, synovial joints function by bones sliding relative to each other, allowing an extensive range of motion and heightened stability compared to fused or cartilaginous joints that function by bending. Using histological and protein expression analysis, we show that reciprocally articulated, cavitated, and lubricated joints are present in elasmobranchs such as skates and sharks but not in cyclostomes such as the sea lamprey. Furthermore, the development of the little skate joints relies on genetic regulatory mechanisms such as BMP and Wnt-signalling, similar to tetrapods. Thus, our results show that synovial joints are present in elasmobranchs but not in cyclostomes. In conclusion, synovial joints originated in the common ancestor of jawed vertebrates. Furthermore, a review of fossil taxa along the gnathostome stem shows that cavitated joints that function by relative sliding of articulating surfaces originated at the common ancestor of all gnathostomes. Our results have consequences for understanding how the evolution of cavitated and lubricated joints in ancient vertebrates impacted behaviors like feeding and locomotion 400 million years ago.

Skeletal muscle function is inferred from the spatial arrangement of myofiber architecture and the molecular and metabolic features of myofibers. Features of myofiber types can be distinguished by the expression of myosin heavy chain (MyHC) isoforms, indicating contraction properties. In most studies, a local sampling, typically obtained from the median part of the muscle, is used to represent the whole muscle. It remains largely unknown to what extent this local sampling represents the entire muscle. Here we studied myofiber architecture over the entire wild type mouse tibialis anterior muscle, using a high-throughput procedure combining automatic imaging and image processing analyses. We reconstructed myofiber architecture from consecutive cross-sections stained for laminin and MyHC isoforms. The data showed a marked variation in myofiber geometric features, as well as MyHC expression and the distribution of neuromuscular junctions, and suggest that muscle regions with distinct properties can be defined along the entire muscle. We show that in these muscle regions myofiber geometric properties align with biological function and propose that future studies on muscle alterations in pathological or physiological conditions should consider the entire muscle.

The aim of this study was to explore and compare patterns of morphological covariation, including symmetrical deviations, between splanchnocranium and the basicranium in Toy rabbit, a type of paedomorphic rabbit. A sample of 32 skulls of adult Toy rabbits was studied on digital pictures on ventral aspects by means of geometric morphometric methods. A set of 7 landmarks were located on the horizontal plane of the splanchnocranial ventral bones (palatine process of the maxillary bone [processus palatinus maxillae] + palatine bone [lamina horizontalis ossis palatini]), and a set of 8 landmarks were on the basicranium (sphenoid [os sphenoidale] + basilar part of the occipital bone [pars basilaris] + bulla tympanica). Both fluctuating and directional asymmetries were detected on both blocks, being the asymmetry more important among splanchnocranial bones. It appeared also a significant relationship (allometry) between size and shape, especially in the basicranium, as well a significant relationship between the two blocks. From results we deduce that, although normally cranial base usually reaches adult size before the face, in paedomorphic animals the face stops its growth earlier than basicranium, resulting in their proportionally reduced splanchnocranium, the typical brachyfacial morphology for paedomorphy. In other words, our results support the hypothesis of an early stop of facial pattern development in neoteny -the retention of juvenile characteristics into adulthood-, which can affect vital structures. So, further research should expand on clinical data of paedomorphic animals in order to advance in the understanding of pathological results of this growth anomaly.

To understand how an extinct species may have moved, we first need to reconstruct the missing soft tissues of the skeleton which rarely preserve, with an understanding of segmental volume and the muscular composition within the body. The Australopithecus afarensis specimen AL 288-1 is one of the most complete hominin skeletons. Whilst it is generally accepted that this species walked with an erect limb, the frequency and efficiency of such movement is still debated. Here, 36 muscles of the pelvis and lower limb were reconstructed in the specimen AL 288-1 using 3D polygonal modelling which was guided by imaging scan data and muscle scarring. Reconstructed muscle masses and configurations guided biomechanical modelling of the lower limb in comparison to a modern human. Muscle moment arms were calculated and summed per muscle group. Simulated error margins were computed using Monte Carlo analyses. Results show that the moment arms of both species were comparable, hinting towards similar limb functionality. Moving forward, the polygonal muscle modelling approach has demonstrated promise for reconstructing the soft tissues of hominins and providing information on muscle configuration and space filling. This approach is recommended for future studies aiming to model musculature in extinct taxa.

BackgroundJoint hyper-resistance is a common symptom in cerebral palsy (CP). It is assessed by rotating the joint of a relaxed patient. Joint rotations also occur when perturbing functional movements. Therefore, joint hyper-resistance might contribute to reactive balance impairments in CP. AimTo investigate relationships between altered muscle responses to isolated joint rotations and perturbations of standing balance in children with CP. Methods & procedures20 children with CP participated in the study. During an instrumented spasticity assessment, the ankle was rotated as fast as possible from maximal plantarflexion towards maximal dorsiflexion. Standing balance was perturbed by backward support-surface translations and toe-up support-surface rotations. Gastrocnemius, soleus, and tibialis anterior electromyography was measured. We quantified reduced reciprocal inhibition by plantarflexor-dorsiflexor co-activation and the neural response to stretch by average muscle activity. We evaluated the relation between muscle responses to ankle rotation and balance perturbations using linear mixed models. Outcomes & resultsCo-activation during isolated joint rotations and perturbations of standing balance was correlated across all levels. The neural response to stretch during isolated joint rotations and balance perturbations was not correlated. Conclusions & implicationsReduced reciprocal inhibition during isolated joint rotations might be a predictor of altered reactive balance control strategies. HighlightsO_LIImpaired reciprocal inhibition might underlie altered balance control in CP. C_LIO_LICo-activation during isolated joint rotations and balance responses is correlated. C_LIO_LIHyperreflexia is not correlated with increased response to perturbations of standing. C_LIO_LIReduced reciprocal inhibition has functional implications. C_LIO_LIIt might be valuable to clinically assess reduced reciprocal inhibition. C_LI What this paper addsIt has been hard to relate alterations in muscle coordination during functional movements to alterations in the muscles response to isolated joint rotations as applied during (clinical) assessments of hyper-reflexia. Here, we performed a more comprehensive assessment of the altered muscle response to isolated joint rotations in children with cerebral palsy (CP) by not only considering muscle activity in response to stretch but also agonist-antagonist co-activation. Muscle co-activation in response to isolated joint rotations in relaxed patients has been attributed to reduced reciprocal inhibition in the spinal cord. We found that muscle co-activation during isolated joint rotations was correlated to muscle co-activation during perturbed standing, an important functional movement. Therefore, increased muscle co-activation during standing balance control might - at least partially - result from reduced reciprocal inhibition in the spinal cord. In contrast, we found very few relations between the mean muscle activity during isolated joint rotations and perturbed standing. This might be due to the sensitivity of the response to stretch to stretch velocity, posture, and baseline muscle activity, all of which largely differed between the two conditions. Our results indicate that clinical assessment of reduced reciprocal inhibition during isolated joint rotations might provide information about balance impairments.

The scaling pattern of the hind limb in Carnivora was determined using a sample of 13 variables measured on the femur, tibia, and calcaneus, of 429 specimens belonging to 141 species. Standardized major axis regressions on body mass were calculated for all variables, using both traditional regression methods and phylogenetically independent contrasts (PIC). Significant differences were found between the allometric slopes obtained with traditional and PIC regression methods, emphasizing the need to take into account phylogenetic relatedness in scaling studies. Overall, the scaling of the carnivoran hind limb conformed to geometric similarity, although some deviations from its predictions (including differential scaling) were detected, especially in relation with swimming adaptations. The scaling pattern of several phyletic lines and locomotor habits within Carnivora was also determined. Significant deviations from the scaling pattern of the order were found in some phyletic lines, but not in the locomotor habit subsamples. This suggests that the scaling of the carnivoran hind limb is both more heavily influenced by phylogenetic relatedness than by locomotor specializations, and more conservative than that of the forelimb. Finally, together with our previous work on the carnivoran forelimb, the results of the present study suggest that, in large non-aquatic carnivorans, size-related increases in bone stresses are compensated primarily by limb posture changes instead of by modifying limb bone scaling. However, increasing bone robusticity might also occur in the forelimb in response to the heavier stresses acting on the forelimbs due to asymmetrical body weight distribution.

This study aims to discriminate cercopithecid taxa of higher taxonomic levels (subfamily, tribe, subtribe, and genus) on the basis of corpus shape in transverse cross-section at the M1-M2 junction and to assess its variation using 2D geometric morphometrics. Specifically, we evaluated the effect of allometry and sexual dimorphism on differences in corpus shape at interspecific and intraspecific levels, respectively. We also investigated whether corpus variation among cercopithecids was following Brownian motion using Pagels {lambda}. Taxonomic discrimination and sexual dimorphism were established using Analysis of Variance on Principal Component scores. Allometry was studied using phylogenetic least-squares regressions and partial least-squares regressions. We demonstrated that, using corpus shape, extant cercopithecids can be significantly discriminated at the subfamilial, tribal, and subtribal levels. In addition, the main axis of variation of the Principal Component Analysis follows a distribution expected under Brownian motion, validating the presence of a phylogenetic signal in corpus shape. Colobines exhibit a robust corpus (superoinferiorly short and transversely broad) with large lateral prominences while cercopithecines have a gracile corpus (superoinferiorly long and transversely thin in its distal portion) with marked corpus fossae in African papionins. Exception to the typical subfamilial or tribal shape pattern exist, with the best examples being Trachypithecus, Presbytis and Pygathrix within colobines, Allenopithecus within Cercopithecini, and Macaca, Theropithecus and Cercocebus within Papionini. Sexual dimorphism is a confounding factor in shape discrimination, as there are significant differences between sexes, notably in Papio anubis, Nasalis larvatus and Procolobus verus . Intriguingly, sexual dimorphism in corpus shape does not seem to follow the dimorphism deduced in canine and molar crown dimensions. This discrepancy is illustrated by the low degree of dimorphism in corpus shape in Piliocolobus badius, despite dimorphic canine and molar dimensions. Overall, our findings concerning corpus shape variation in cercopithecids will greatly benefit to paleontological studies that seek to identify taxa in the fossil record, and to neontological studies aiming to explore the ecomorphological value of the cercopithecid mandible.

BackgroundThe severity of pectus excavatum (PEX) as measured by Haller index (HI) does not always correlate with symptoms of aerobic capacity. Transthoracic echocardiograms (TTE) are generally reported as normal which may influence the pediatricians decision to refer for corrective surgery. The aim of this study was to find a reproducible TTE marker as an indicator of right ventricular compression and compare it to severity of PEX and cardiopulmonary exercise test (CPET) indices. MethodsThe study included patients aged 10-19 years with an institution-based protocol for preoperative PEX evaluation with TTE, chest computed tomography (CT) for HI, and CPET from 2015-2021. We divided the patients into two groups, mild/moderate PEX (HI 2-3.5) and severe PEX (HI > 3.5). Tricuspid valve annulus size (TVAS) was compared between the groups as well as with other CPET and TTE indices using Students t-test. Spearmans rank correlation coefficient was used to evaluate correlations between the severity of PEX by HI with the TTE and CPET parameters. ResultsOf the 124 patients, 82 (66.1%) had severe PEX and 42 (33.9%) had mild/moderate PEX. The mean TVAS z-scores in the mild/moderate PEX group was -1.98(SD 0.51) and -2.24 (SD 0.71) in the severe PEX group (p 0.046). There was a negative correlation between the TVAS z-score and the severity of PEX but this was not statistically significant (r = -0.154, p = 0.087). There was no significant difference in peak oxygen uptake (peak VO2) or left ventricular ejection fraction between the severity groups. However, the TVAS z-score positively correlated with peak VO2 (median 43 ml/kg/min, r = 0.023, p = 0.01), peak VO2 percent predicted (median 86%, r = 0.19, p = 0.04), and O2 pulse (median 12.7 ml/beat, r = 0.20, p = 0.025), and negatively correlated with VE/VCO2 (median 29, r = -0.23, p = 0.01). ConclusionThe severity of PEX by HI does not factor in the location of cardiac compression and may not always reflect the degree of cardiac limitation. The Tricuspid valve annulus size is a good TTE indicator of cardiopulmonary compromise from PEX. A TVAS z score <-2 is a good predictor of cardiac compromise in pediatric PEX. This may provide additional functional parameters in the decision-making process for corrective surgery.

PurposeThe shape of the peroneus brevis tendon may contribute to the development of split tears, but a classification of its anatomical variants on transverse section in vivo is lacking. This study aimed to validate a proposed classification system for peroneus brevis tendon morphology on the transverse cross section on magnetic resonance imaging (MRI). MethodsWe analysed 130 normal peroneus brevis tendons (power >0.8, = 0.05, effect size = 0.31) on consecutively selected ankle MRI performed at 3T. We excluded patients with fractures, ligament injuries, or peroneal tendon pathology. Seven independent raters classified tendons into four morphological categories: general flat, flat with a lateral bulge, flat with a medial bulge, and oval. Inter-rater reliability was assessed using Cohens kappa, Gwets AC1, and Fleiss kappa. We evaluated classification robustness using F1 score, receiver operating characteristic analysis, and precision-recall metrics. ResultsConsensus classification showed 37.7% of tendons were general flat, 20.8% flat with a lateral bulge, 19.2% flat with a medial bulge, and 22.3% oval. Inter-rater agreement was substantial, with Fleiss kappa of 0.69 (95% CI 0.63-0.75). Cohens kappa ranged from 0.59 to 0.87, and Gwets AC1 from 0.58 to 0.87, confirming strong pairwise agreement. Classification performance was high (area under the curve = 0.89), and majority voting further improved agreement (F1 score = 0.93). The most common misclassification occurred between oval and flat with a medial bulge. ConclusionThis proposed classification is robust and reliable, offering a validated framework for consistent tendon evaluation in both clinical and research settings.