Journal of Anatomy最新文献

Modern trionychids (Testudines, Cryptodira) have a pan-tropical distribution, but their range encompassed Central Europe during the Miocene. However, their true Neogene northernmost limit is uncertain because of limited Miocene exposures in the northern half of Europe, including Poland. Here, we address this problem, describing the first Polish remains from this family, coming from three new Middle Miocene vertebrate localities. The material includes isolated shell fragments and an incomplete skull, studied using computed tomography. Through a detailed review of the variation of cranial characters in extant and extinct trionychids, as well as considering the already existing occurrences of the family in the Miocene of Europe, we propose a tentative assignment for this last specimen to Trionyx cf. vindobonensis. This is somehow unexpected since the geographically closest diagnostic records of the family from the Early Miocene of Czechia belong to Rafetus. These new occurrences hint toward an environment still suitable for thermophilic organisms between the Mid-Miocene Climatic Optimum and Late Miocene "washhouse" climate in the northern part of Central Europe.

Recent advances in the study of cross-sectional geometry have highlighted the value of ontogenetic data for understanding skeletal function, development, and biomechanics. While multiple protocols for extracting bone cross-sections have been validated in limb long bones, the clavicle (despite its unique curvature and developmental trajectory) has received little methodological scrutiny. Critically, two main alignment strategies can be used to extract clavicular midshaft cross-sections from 3D data, yet their comparability remains untested. This lack of standardization compromises the reproducibility and interpretability of clavicular cross-sectional property (CSP) data, particularly in developmental studies. This study evaluates two published alignment protocols for clavicular CSP extraction in non-adults: one that follows the natural curvature of the bone and one based on a standardized transverse plane. We analyzed high-resolution computed tomography scans of 81 individuals (ages 0.5-20 years) from a medieval osteological collection. Midshaft cross-sections were generated using both methods for each clavicle, and CSP variables were calculated. Comparative analysis involved linear regressions, Bland-Altman plots, and percent prediction error (%PE) to assess both systematic bias and the magnitude and direction of error between methods. While total area showed a significant proportional bias and %PE values exceeding the 5% acceptable error threshold, cortical subperiosteal area exhibited a consistent but non-proportional bias, indicating uniform overestimation across specimens. Z_p and J showed the largest directional errors, reflecting greater sensitivity to alignment differences. These discrepancies are not merely numerical but reflect fundamental geometric divergences introduced by the alignment strategy. As a result, CSP values obtained from these two protocols are not directly interchangeable. Together, Bland-Altman and %PE analyses provide a robust framework for evaluating agreement and highlight where pooling data across alignment strategies may be justified and where it is not. Our findings underscore the importance of methodological consistency in clavicular cross-sectional analyses. Given the anatomical complexity of the clavicle and its developmental plasticity, alignment strategy exerts a significant influence on derived CSP values. We recommend that future studies clearly report alignment criteria and avoid direct comparisons between datasets processed with different protocols.

The region of the gastric lesser curvature is reported to differ from other parts of the stomach in lacking rhythmic muscle movement in its proximal part, by fewer enteric nerve cells being present and by differences in distributions of interstitial cells of Cajal (ICC). Because detailed documentation of differences is lacking, we made a thorough investigation of the lesser curvature region. A substantial part of the lesser curvature region had a sparse ganglionated myenteric plexus (about 25% of the density of occurrence of ganglia in other regions). This overlapped with an area lacking longitudinal muscle, in which the enteric ganglia were serosal, at the circular muscle surface. The serosal ganglia lacked associated ICC, unlike other parts of the corpus and antrum, but ICC were numerous in the circular muscle. Close to the oesophagus, enteric ganglia were additionally between the circular and oblique muscle. Immunohistochemical investigation and muscle intracellular recording indicated that there was effective circular muscle innervation throughout the lesser curvature region, although a site of lower effectiveness of inhibitory innervation was found in the proximal part of the lesser curvature region. There was a gradient of reducing excitatory fibre innervation density towards the lesser curvature. Excitatory effects on the muscle were deduced to be indirect, as they are in the adjacent antrum. MRI of gastric movements in vivo revealed large amplitude propulsive waves of contraction at the lesser curvature towards the pylorus, and substantially, fourfold, lower amplitudes closer to the base of the oesophagus. We also describe that the major arterial supplies to the rat stomach radiate from the lesser curvature region and that mucosal specialisation does not correspond with functional or anatomical divisions of the stomach at the lesser curvature or elsewhere. Running parallel and lateral to the line of the lesser curvature were the previously reported esophago-pyloric ligaments that dynamic MRI suggested contract and relax during active antral movements. Thus, there are specialised features that distinguish the region of the lesser curvature from other gastric regions. At the proximal part of the lesser curvature, longitudinal muscle is absent, ganglia are sparse, ICC associated with ganglia are largely absent, and rhythmic circular muscle contractions have substantially lower amplitudes than more distally (in the 5 mm adjacent to the pylorus). The reduced amplitudes of contraction during peristalsis may be protective against mechanical force on the arteries and nerves that enter the stomach at the proximal lesser curvature region.

The ciliary body (CB) represents an immunoregulatory compartment for the ocular system and we questioned whether local immune regulation in the CB in humans could be under neural control. In this study, we explored whether the human CB contains a sympathetic-macrophage neuroimmune link. Seven right eyes from donated cadavers (five male, two female) were enucleated. After removal of the cornea, lens, and vitreous body, each eye was divided into quadrants. One quadrant per eye was processed for light microscopy to assess overall morphology, general and sympathetic nerve presence, varicosities, macrophages, and the proximity of sympathetic nerves to macrophages. Additional quadrants (whole-mount samples) were examined with three-dimensional (3D) confocal microscopy to visualize the spatial relationship between sympathetic nerves and macrophages and to determine whether these macrophages expressed β₂-adrenergic receptors. Our study shows that the human CB contains sympathetic nerves of which a significant amount was spatially associated to β2-adrenergic receptor expressing macrophages. The current study provides morphological evidence for a possible sympathetic-macrophage ocular neuroimmune link in humans which may constitute a novel field for the study of degenerative and inflammatory eye disease. Further understanding of the CB sympathetic nerves and their immunomodulatory capacity is needed for the development of future therapeutics.

The scapula connects the forelimb to the axial skeleton, and its morphology varies among primates, showing similarities across species with comparable locomotor behaviours, particularly forelimb-suspensory locomotion. The serratus anterior (SA), levator scapulae (LS) and rhomboid (Rh), collectively referred to as the LSR, connect the scapula to the trunk. The morphology of the LSR shows interspecific variation among primates, but its diversity and determinants have not been fully elucidated. This study explored the morphological adaptations in primate locomotor evolution by analysing the morphology and innervation of the LSR. We examined 27 limbs of 11 primate species across Catarrhini, Platyrrhini and Strepsirrhini. Based on the LS origin, the LSR were classified as: Type I (Continuous type), where LS is attached to all the cervical vertebrae and continuous with the SA; Type II (Separated type), where LS is attached to the first to fourth cervical vertebrae and separated from the SA; and Type III (Intermediate type), where the demonstrated features are between Types I and II. In all specimens, the LSR were innervated by C3-8, with C4-7 consistently present. In Type II, C5 innervated both the lower LS and the upper SA, whereas in Type I and Type III, C5 innervated the lower LS. Type I was found across all groups, suggesting its representation as the ancestral form. Both Type II and Type III appear to be derived from the Type I. In Type II, separation of LS and SA reflects division of the C5-innervated region rather than loss of the lower LS. Type II occurred only in Hominoidea, suggesting increased functional demands on the upper SA. Type III is considered a subtype of Type I, retaining C5 innervation in the LS despite morphological separation. The occurrence of Type III in small-bodied species of the family Cebidae suggests that it represents a subtype associated with variation in body size. These findings suggest that the morphology of the LSR in primates is shaped not only by phylogenetic background but also by species-specific functional demands.

Shoulder anatomy is complex, varying in shape and pose. Studies have related bone shape and joint function, which can predict each other but not yet in the shoulder. This project aims to investigate bone shape and pose relationships in the healthy shoulder via partial least square regressions (PLSR). Sixty-eight registered humeri, scapulae, and clavicles were segmented (47 males and 15 females, age: 30.7 ± 9.5 years) from medical images (computed tomography and magnetic resonance images) and constituted the shape input (principal component analysis scores). Local bone coordinate systems (three axes and origin) composed the pose information. PLSR analyses were conducted using the shape of one or all three bones to predict the pose and vice versa. The main variation mode explained scaling for shape (38% variation explained) and the three shoulder bones' anteroposterior (AP) and superoinferior translations, and humeral and clavicular AP rotations for pose (8%). There was no difference in explained pose variation whether using the humerus, scapula, or clavicle as predictors. However, pose variations were more intertwined between the scapula and the clavicle when using all three shoulder bones as predictors compared to single-bone models, suggesting a stronger coupling between these bones that likely originates from their shared anatomical constraints with the thoracic cage. The dataset showed a mild to excellent fit to the analysis (R² = 0.4-0.9); however, the findings lacked generalizability (Q² = 0.0-0.1), suggesting that PLSRs require additional information-such as soft tissue contributions-to enhance predictive performance. These findings have potential clinical applications in surgical planning, where individual bone shape could be used to estimate native shoulder poses in trauma patients; however, stronger predictive models incorporating additional anatomical or biomechanical parameters are needed to support such use.

Optical coherence tomography (OCT) is a modern imaging technology crucial for diagnosing retinal diseases by providing high-resolution, non-invasive images of biological tissues. Despite the widespread use of rabbits in ophthalmological research due to their anatomical similarities to the human eye, comprehensive data on normal retinal thickness in rabbits using OCT is limited. This study was conducted with the objective of measuring retinal thickness in rabbits using an OCT device specifically designed for their eyes. The study included 42 rabbits grouped according to age (3-6 and 12 months) and gender, and ethical guidelines for animal research were followed. Using the Envisuu R2310 OCT device, retinal thickness was measured at various distances from the optic disc. The measurements showed that there was no significant difference between genders, but there were significant age-related changes, with thickness peaking at 6 months and thinning at 12 months. The superior retina consistently appeared to be the thinnest region in all age groups. The use of a rabbit-specific OCT device provided accurate, high-resolution images, addressing previous challenges in measurement accuracy. The findings highlight the significance of age in retinal thickness variations, aligning with human studies showing age-related thinning and emphasizing the need for age control in rabbit retinal research. This study provides a valuable reference for future ophthalmological research and advances in developing rabbit disease models, offering insights into age-related retinal changes and enhancing the potential for scientific investigations using the OCT method.

Calcaneal spurs are shown to be increasingly prevalent in modern populations and often contribute to forming heel and foot pain. There are multiple hypotheses for their formation, including exercise, prolonged standing and obesity. The impact of these spurs on foot biomechanics remains unclear; it is suggested that their presence may contribute to enthesial avulsion forces. This study aimed to determine the avulsion properties of the plantar aponeurosis enthesis with and without spurs. Twenty-four feet from 15 cadavers donated to the Department of Anatomy at the University of Otago were used for this study. Tissues were X-rayed to determine the presence of spurs. The donor feet were dissected to isolate the calcanei. These were then mounted in a custom-developed 3D-printed clamping rig to perform tensile testing of the plantar calcaneal enthesis to determine pull-out forces of the central band of the plantar fascia. Biomechanical testing showed no statistically significant differences in avulsion properties between the spur (n = 7) and non-spur (n = 14) samples in any of the avulsion parameters investigated: F_max (1121 ± 358 N vs. 953 ± 283 N, mean ± SD, p = 0.302) and εF_max (53 ± 11% vs. 51 ± 13%, mean ± SD, p = 0.660). Despite this, the avulsion parameters were highly variable. The results of this study indicate that the pull-out force of the central band of the plantar fascia is unrelated to the presence of spurs. Therefore, it is less likely that plantar spurs fulfill a biomechanical function within the plantar fascia complex.

Quantifying strain in the free Achilles tendon (AT_F) is essential for understanding its mechanical function, yet existing in vivo studies report inconsistent strain values, even under comparable loading. These discrepancies are partly due to limitations of conventional two-dimensional (2D) imaging, which cannot fully capture the tendon's complex three-dimensional (3D) geometry. This study presents a novel MRI-based framework for assessing 3D centroid strain of the AT_F under passive ankle rotation. Eighteen healthy adults (10 females, 8 males, age: 24.4 ± 4.0 years) underwent static MRI scans at three joint angles (20° plantar flexion, neutral, and 20° dorsiflexion), from which 3D and 2D AT_F lengths were computed. Results showed that the 2D method failed to detect physiologically relevant strain and even indicated apparent shortening. On the other hand, the 3D method revealed significant but only a small magnitude of elongation of the AT_F (1.2% ± 0.3 from 20° plantar flexion to 20° dorsiflexion). Additionally, an offset simulation demonstrated that small sagittal-plane misalignments (2-4 mm) could introduce substantial variations of the AT_F length in the 2D measurements (2.8-6.3 mm). Such systematic errors can be due to the combined effects of imaging plane misalignment and complex features of distal soleus morphology. Collectively, these findings clearly show the limitations of the conventional 2D approaches when determining AT_F length and its changes upon loading, underscore the superior accuracy of 3D MRI in detecting subtle AT_F deformations, and provide critical insights into the anatomical and methodological sources of error in prior strain assessments.

Ulnar curvature has long been recognized as an indicator of locomotor behavior in mammals, although its relevance has yet to be thoroughly tested in a phylogenetically restricted and functionally diverse group. Extant cercopithecids exhibit a wide range of quadrupedal locomotor behaviors and substrate use, making them an ideal benchmark to test form-function relationships between ulnar curvature and locomotion. While their ulnar curvature has been partly investigated through its anteroposterior curvature, the mediolateral curvature remains largely unexplored. We hypothesized that ulnar curvature covary with habitual substrate use (i.e., terrestrial versus arboreal) and locomotor behaviors (e.g., suspension versus climbing) in both sagittal and coronal planes. In this study, we provide a comprehensive assessment of ulnar curvature in extant cercopithecids, based on an extensive and taxonomically diverse sample of 23 species and 167 individuals, to assess inter- and intraspecific morphological variation. As expected, our analyses confirm previous findings regarding anteroposterior curvature, with terrestrial quadrupeds exhibiting an anteriorly convex ulna, and arboreal taxa showing an anteriorly concave ulna. Regarding mediolateral curvature, arboreal taxa exhibit a lateral convexity, while terrestrial quadrupeds show a more complex sigmoid curvature, possibly reflecting resistance to the various mediolateral constraints generated by hand postures. Although the two curvatures seem to distinguish arboreal and terrestrial locomotor behaviors, their moderate covariation (~55%) suggests that curvature responds to partially distinct biomechanical factors. Suspensory taxa, previously thought to possess relatively straight ulnae, are revealed to have noticeable anteriorly concave bones, consistent with notable brachialis contraction during suspension. Unexpectedly, climbers show intermediate morphologies between arboreal and terrestrial quadrupeds, supporting the idea that ulnar curvature does not allow their distinction, implying that this behavior is difficult to infer through ulnar curvatures.