Shape variations of pelvis in different classes of dogs using geometric morphometry.

The ossa coxae are the bones that connect the hindlimbs to the axial skeleton. The right and left os coxae join at the median plane to form the pelvis. In this study, variations in pelvis shape and the asymmetric structure of the pelvis were investigated across different classes of dogs. To achieve this, computed tomography images of the pelvis were obtained from 35 dogs, and 3D modelling of the pelvis was created. Subsequently, 45 landmarks were identified on these models. As a result of the Principal Component Analysis, the shape variation was observed in the pelvic canal and crista iliaca. Directional asymmetry between Principal Component 1 and Principal Component 2 accounted for 33.84% of the total variation, while fluctuating asymmetry contributed 23.66%. Canonical variate analysis revealed that canonical variate (CV) 1 explained 56.56% of the total variation between groups, with CV 2 explained 28.98%. Male dogs exhibited greater pelvic variation than females. Procrustes ANOVA indicated that the greatest proportion of shape variation corresponds to the effect of differences among individuals. While directional asymmetry was statistically significant, fluctuating asymmetry was not. Male dogs displayed more pronounced pelvic shape asymmetry, typically towards the right. Gundogs had a narrower pelvic canal and a wide crista iliaca, whereas terriers had a wider pelvic canal and smaller crista iliaca in shape. Geometric morphometry enables statistical analysis and the derivation of average shapes from samples, making it a vital tool in veterinary anatomy. This study provides insights into pelvic geometric morphometry across different classes of dogs.

An arterial map of the uterine artery - a tool for endovascular and gynecological procedures.

INTRODUCTION: The anatomy of the uterine artery (UA) is highly complex, demonstrating various patterns of origin and course. The main objective of the present study is to provide the first anatomical heat map of the UA, demonstrating the location of its origin and course in the pelvis. METHODS: In July 2022, an assessment was conducted on the findings from 40 consecutive female patients who had undergone computed tomography angiography of the abdomen and pelvis. Morphometric features of the UA and its associated anatomical area were gathered in 19 categories. RESULTS: The presented results are based on a total of 58 UAs. 40 UAs originated from the anterior trunk of the internal iliac artery (69.0%), 16 of the UAs originated from the umbilical artery (27.6%), and the remaining two originated from the inferior gluteal artery (3.4%). The median diameter of the UA at its origin was found to be 3.20 mm (LQ = 2.63; HQ = 3.89). CONCLUSION: The anatomy of the UA is highly complex, showcasing variable topography, origin patterns, and morphometric properties. In the present study, a novel arterial map of this vessel was made, highlighting the diversity in its origin location and course. In our studied cohort, the UA originated most commonly from the anterior trunk of the internal iliac artery (69.0%), as described in the major anatomical textbooks. Having adequate knowledge about the anatomy of this artery is of immense importance in various gynecological and endovascular procedures, such as hysterectomies and embolizations.

Sexual dimorphism of the human fetal pelvis exists at the onset of primary ossification.

Human adolescent and adult skeletons exhibit sexual dimorphism in the pelvis. However, the degree of sexual dimorphism of the human pelvis during prenatal development remains unclear. Here, we performed high-resolution magnetic resonance imaging-assisted pelvimetry on 72 human fetuses (males [M]: females [F], 34:38; 21 sites) with crown-rump lengths (CRL) of 50-225 mm (the onset of primary ossification). We used multiple regression analysis to examine sexual dimorphism with CRL as a covariate. Females exhibit significantly smaller pelvic inlet anteroposterior diameters (least squares mean, [F] 8.4 mm vs. [M] 8.8 mm, P = 0.036), larger subpubic angle ([F] 68.1° vs. [M] 64.0°, P = 0.034), and larger distance between the ischial spines relative to the transverse diameters of the greater pelvis than males. Furthermore, the sacral measurements indicate significant sex-CRL interactions. Our study suggests that sexual dimorphism of the human fetal pelvis is already apparent at the onset of primary ossification.

Exploring the Topography of the Obturator Artery and Corona Mortis: a Detailed Analysis with Surgical Implications.

INTRODUCTION AND HYPOTHESIS: The obturator artery (ObA) is described as a branch of the anterior division of the internal iliac artery. It arises close to the origin of the umbilical artery, where it is crossed by the ureter. The main goal of the present study was to create an anatomical map of the ObA demonstrating the most frequent locations of the vessel's origin and course. METHODS: In May 2022, an evaluation of the findings from 75 consecutive patients who underwent computed tomography angiography studies of the abdomen and pelvis was performed. RESULTS: The presented results are based on a total of 138 arteries. Mostly, ObA originated from the anterior trunk of the internal iliac artery (79 out of 138; 57.2%). The median ObA diameter at its origin was found to be 3.34 mm (lower quartile [LQ] = 3.00; upper quartile [UQ] = 3.87). The median cross-sectional area of the ObA at its origin was found to be 6.31 mm2 (LQ = 5.43; UQ = 7.32). CONCLUSIONS: Our study developed a unique arterial anatomical map of the ObA, showcasing its origin and course. Moreover, we have provided more data for straightforward intraoperative identification of the corona mortis through simple anatomical landmarks, including the pubic symphysis. Interestingly, a statistically significant difference (p < 0.05) between the morphometric properties of the aberrant ObAs and the "normal" ObAs originating from the internal iliac artery was found. It is hoped that our study may aid in reducing the risk of serious hemorrhagic complications during various surgical procedures in the pelvic region.

Evolution of the human birth canal.

It seems puzzling why humans have evolved such a small and rigid birth canal that entails a relatively complex process of labor compared with the birth canal of our closest relatives, the great apes. This study reviewed insights into the evolution of the human birth canal from recent theoretical and empirical studies and discussed connections to obstetrics, gynecology, and orthopedics. Originating from the evolution of bipedality and the large human brain million years ago, the evolution of the human birth canal has been characterized by complex trade-off dynamics among multiple biological, environmental, and sociocultural factors. The long-held notion that a wider pelvis has not evolved because it would be disadvantageous for bipedal locomotion has not yet been empirically verified. However, recent clinical and biomechanical studies suggest that a larger birth canal would compromise pelvic floor stability and increase the risk of incontinence and pelvic organ prolapse. Several mammals have neonates that are equally large or even larger than human neonates compared to the size of the maternal birth canal. In these species, the pubic symphysis opens widely to allow successful delivery. Biomechanical and developmental constraints imposed by bipedality have hindered this evolutionary solution in humans and led to the comparatively rigid pelvic girdle in pregnant women. Mathematical models have shown why the evolutionary compromise to these antagonistic selective factors inevitably involves a certain rate of fetopelvic disproportion. In addition, these models predict that cesarean deliveries have disrupted the evolutionary equilibrium and led to new and ongoing evolutionary changes. Different forms of assisted birth have existed since the stone age and have become an integral part of human reproduction. Paradoxically, by buffering selection, they may also have hindered the evolution of a larger birth canal. Many of the biological, environmental, and sociocultural factors that have influenced the evolution of the human birth canal vary globally and are subject to ongoing transitions. These differences may have contributed to the global variation in the form of the birth canal and the difficulty of labor, and they likely continue to change human reproductive anatomy.

New insights into patterns of integration in the femur and pelvis among catarrhines.

OBJECTIVES: Integration reflects the level of coordinated variation of the phenotype. The integration of postcranial elements can be studied from a functional perspective, especially with regards to locomotion. This study investigates the link between locomotion, femoral structural properties, and femur-pelvis complex morphology. MATERIALS AND METHODS: We measured (1) morphological integration between femoral and pelvic morphologies using geometric morphometrics, and (2) covariation between femoral/pelvic morphologies and femoral diaphyseal cross-sectional properties, which we defined as morpho-structural integration. Morphological and morpho-structural integration patterns were measured among humans (n = 19), chimpanzees and bonobos (n = 16), and baboons (n = 14), whose locomotion are distinct. RESULTS: Baboons show the highest magnitude of morphological integration and the lowest of morpho-structural integration. Chimpanzees and bonobos show intermediate magnitude of morphological and morpho-structural integration. Yet, body size seems to have a considerable influence on both integration patterns, limiting the interpretations. Finally, humans present the lowest morphological integration and the highest morpho-structural integration between femoral morphology and structural properties but not between pelvic morphology and femur. DISCUSSION: Morphological and morpho-structural integration depict distinct strategies among the samples. A strong morphological integration among baboon's femur-pelvis module might highlight evidence for long-term adaptation to quadrupedalism. In humans, it is likely that distinct selective pressures associated with the respective function of the pelvis and the femur tend to decrease morphological integration. Conversely, high mechanical loading on the hindlimbs during bipedal locomotion might result in specific combination of structural and morphological features within the femur.

Reliability of the sonographic evaluation for cervical length and elastography with pelvic parameters in term pregnancy by experienced operators with varying levels of experience.

OBJECTIVE: To assess the reliability of sonographic measurements of six cervical and pelvic parameters by three sonographers with varying levels of experience. METHODS: A cross-sectional study was conducted in pregnant women with a gestational age of ≥39 weeks. Each pregnant woman was examined by two sonographers with different levels of experience. Six parameters were measured: cervical length (CL), cervical strain elastography (extrinsic type), posterior cervical angle (PCA), fetal head-to-perineum distance (FHPD), fetal head-to-pubic symphysis distance (FHSD), and angle of progression (AOP). Intra- and interobserver reliabilities were assessed using the intraclass correlation coefficient with a 95% confidence interval. Pearson pairwise correlation coefficients were used to analyze the correlation between the parameter values. RESULTS: In all, 66 pregnant women were enrolled in this study. We found excellent intraobserver reliability for measurements of CL, PCA, FHPD, FHSD, and AOP and good-to-excellent intraobserver reliability for cervical strain values in the cross-sectional view of the endocervix in the internal os area and cross-sectional view of the entire cervix in the internal os area. Interobserver reliability was excellent for all pelvic parameters, except for the FHPD. Strain values were moderate to excellent in the area of the internal os. A significant negative correlation between CL and strain values at the internal os was observed. CONCLUSIONS: Pelvic parameters, except for FHPD, have excellent intra- and interobserver reliabilities. The high reproducibility of CL and cervical strain elastography at the internal os level, with a negative correlation between these two parameters, may play an important role in predicting successful induction of labor.

Retroperitoneoscopy of the presacral space in horses: Surgical access and anatomy.

BACKGROUND: Surgical approaches to the equine rectum and perirectal area are described in the literature. However, surgeries in this region can be challenging. OBJECTIVE: To describe the surgical anatomy of the presacral space and to evaluate its access using a retroperitoneoscopic approach. STUDY DESIGN: Ex vivo experiment. METHODS: Preliminary dissections were performed in two cadavers to define the boundaries of the presacral space and to determine portal locations for the surgical approach. After that, nine cadavers were used for experimental presacral retroperitoneoscopic procedure in a standing position. Following retroperitoneoscopy, cadavers were dissected to confirm the anatomical structures observed during the endoscopic procedures, to control the location of each portal and to record iatrogenic trauma. RESULTS: The presacral space was bordered by the vertebral column from the ventral aspect of lumbosacral promontorium to the first coccygeal vertebra dorsally and by the presacral fascia and peritoneum ventrally. Lateral limits were composed of the sacrosciatic ligament and transversalis fascia. Cranial and caudal borders were composed of the peritoneum and coccygeal and levator ani muscles respectively. Retroperitoneoscopic portals were placed between the external anal sphincter and semimembranosus muscles and between the base of the tail and the external anal sphincter muscle through the anococcygeal fascia to enter the space by its caudal border. The retroperitoneal space was reached in all cases and the dorsal and lateral aspects of the rectum were visualised after creation of a working space. MAIN LIMITATIONS: Use of cadaver specimens do not permit to evaluate the tolerance in living animals and the surgical complications such as rectal damage, haemorrhage and infection. CONCLUSION: This study provides an anatomical description and surgical access of the presacral space with a minimal invasive approach. Retroperitoneoscopy allows access to the rectum and the dorsal aspect of the pelvis.

The influence of lumbosacral transitional vertebrae on lumbar lordosis and the angle of pelvic incidence.

Pelvic incidence and lumbar lordosis have only normative values for spines comprising five lumbar and five sacral vertebrae. However, it is unclear how pelvic incidence and lumbar lordosis are affected by the common segmentation anomalies at the lumbo-sacral border leading to lumbosacral transitional vertebrae, including lumbarisations and sacralisations. In lumbosacral transitional vertebrae it is not trivial to identify the correct vertebral endplates to measure pelvic incidence and lumbar lordosis because ontogenetically the first sacral vertebra represents the first non-mobile sacral segment in lumbarisations, but the second segment in sacralisations. We therefore assessed pelvic incidence and lumbar lordosis with respect to both of these vertebral endplates. The type of segmentation anomaly was differentiated using spinal counts, spatial relationship with the iliac crest and morphological features. We found significant differences in pelvic incidence and lumbar lordosis between lumbarisations, sacralisations and the control group. The pelvic incidence in the sacralised group was mostly below the range of the lubarisation group and the control group when measured the traditional way at the first non-mobile segment (30.2°). However, the ranges of the sacralisation and lubarisation groups were completely encompassed by the control group when measured at the ontogenetically true first sacral vertebra. The mean pelvic incidence of the sacraliation group thus increased from 30.2° to 58.6°, and the mean pelvic incidence of the total sample increased from 45.6° to 51.2°, making it statistically indistinguishable from the control sample, whose pelvic incidence was 50.2°. Our results demonstrate that it is crucial to differentiate sacralisations from lumbarisation in order to assess the reference vertebra for pelvic incidence measurement. Due to their significant impact on spino-pelvic parameters, lumbosacral transitional vertebrae should be evaluated separately when examining pelvic incidence and lumbar lordosis.

DSP2 for sex determination of miscegenated contemporary hip bones.

The bones of the human pelvis are used in sexual diagnosis generating a high level of accuracy for this type of identification. Morphological and/or morphometric methods are used in the identification of sex. Sexual dimorphism may be affected by ethnic differences in the population. One of the methods for determining sex using hip bone is the 'Diagnose Sexuelle Probabiliste (DSP)' or Probabilistic Sexual Diagnosis (DSP) method. The method presents a new version (Probabilistic Sexual Diagnosis v.2-DSP2) more advisable to be used because it has a more up-to-date database. The objective of this study is to investigate the applicability of the DSP2 method in a population in the Northeast region of Brazil. We used 128 hip bones, 50 female and 78 males, aged between 17 and 101 years, belonging to the Laboratory of Human Identification and Forensic Osteology of the University Federal Government of Pernambuco. The research was conducted between 2019 and 2020 and approved by the Research Ethics Committee of the Federal University of Pernambuco no. 43228015.0.0000.5208. The probability equal to or greater than 0.95 was used as the limit for the determination of sex, and the results were compared with the actual sex of each bone. In the Brazilian collection study, it was observed that the percentage of sex estimation provided by the DSP2 tool using all reference samples was 71.09%, and accuracy was 64.06%. In the analysis of the gender estimate, 82.0% and 78% were obtained for females and males, respectively. Regarding accuracy, it was 64.10% and 55.13% for females and males, respectively. In the contemporary osteological collection of the Northeast region of Brazil, which presents immigrant peoples, we obtained a high index of assertiveness in the DSP2 method. The study concluded that the DSP2 method is important for determining the sex of human skeletons in a miscegenated population.

Embryonic development of the pelvic girdle and hindlimb skeletal elements in Anilius scytale (Linnaeus, 1758) (Serpentes: Aniliidae).

Anilius scytale is the sister lineage of all other alethinophidian snakes. Morphology of the hind limb complex in adult A. scytale (Aniliidae) has been documented. We herein, for the first time, describe the embryology of the skeletal elements of its hind limb and pelvic girdle and contextualize the evolution of these structures. We identified pregnant females of A. scytale in the Herpetology Collection of the Museu Paraense Emílio Goeldi and separated 40 embryos. The embryos were sequentially staged using external and internal anatomy, collectively comprising a developmental series representing six stages. We cleared-stained one specimen of stages 31, 34, 36, and 37. Using the embryological information gleaned from A. scytale, we reinterpret evidence relating to the ossification of the pelvis and hindlimbs. In A. scytale hindlimb buds develop as transient structures that developed before Stage 30 and regresses in subsequent stages. There is no external or internal evidence of the forelimb or scapular girdle. From Stage 31 onwards the ischium, pubis, ilium, femur and zeugopodial cartilages are visible. Pubis and femur ossify towards the end of embryonic life, and cloacal spurs do not develop in the embryo. Skeletal elements of the hindlimb and pelvic girdle develop initially in the ventral zone of the cloaca-tail region. In subsequent stages the hindlimb and pelvic girdle elements migrate dorsally, with the pubis/ischium positioned medial to the ribs. A similar process may be associated with the achievement of the condition of the pelvic girdle in adults of scolecophidians, pythonids and boids.

Testing the reliability of the rearticulation of osteological primate pelves in comparative morphological studies.

The evolution of human pelvic form is primarily studied using disarticulated osteological material of living and fossil primates that need rearticulation to approximate anatomical position. To test whether this technique introduces errors that impact biological signals, virtual rearticulations of the pelvis in anatomical position from computed tomography scans were compared with rearticulated models from the same individuals for one female and one male of Homo sapiens, Pan troglodytes, Macaca mulatta, Lepilemur mustelinus, Galago senegalensis, and Nycticebus pygmaeus. "Cadaveric" pelvic bones were first analyzed in anatomical position, then the three bones were segmented individually, intentionally scattered, and "rearticulated" to test for rearticulation error. Three-dimensional landmarks and linear measurements were used to characterize the overall pelvis shape. Cadaveric and rearticulated pelves were not identical, but inter-specific and intra-specific shape differences were higher than the landmarking error in the cadaveric individuals and the landmarking/rearticulation error in the rearticulated pelves, demonstrating that the biological signal is stronger than the noise introduced by landmarking and rearticulation. The rearticulation process, however, underestimates the medio-lateral pelvic measurements in species with a substantial pubic gap (e.g., G. senegalensis, N. pygmaeus) possibly because the greater contribution of soft tissue to the pelvic girdle introduces higher uncertainty during rearticulation. Nevertheless, this discrepancy affects only the caudal-most part of the pelvis. This study demonstrates that the rearticulation of pelvic bones does not substantially affect the biological signal in comparative 3D morphological studies but suggests that anatomically connected pelves of species with wide pubic gaps should be preferentially included in these studies.

Hindlimb and pelvic anatomy of Caiman yacare (Archosauria, Pseudosuchia): Myology and osteological correlates with emphasis on lower leg and autopodial musculature.

The anatomy of the archosaurian pelvis and hindlimb has adopted a diversity of successful configurations allowing a wide range of postures during the evolution of the group (e.g., erect, sprawling). For this reason, thorough studies of the structure and function of the pelvic and hindlimb musculature of crocodylians are required and provide the possibility to expand their implications for the evolution of archosaurian locomotion, as well as to identify potential new characters based on muscles and their bony correlates. In this study, we give a detailed description of the pelvic and hindlimb musculature of the South American alligator Caiman yacare, providing comprehensive novel information regarding lower limb and autopodial muscles. Particularly for the pedal muscles, we propose a new classification for the dorsal and ventral muscles of the autopodium based on the organisation of these muscles in successive layers. We have studied the myology in a global background in which we have compared the Caiman yacare musculature with other crocodylians. In this sense, differences in the arrangement of m. flexor tibialis internus 1, m. flexor tibialis externus, m. iliofibularis, mm. puboischiofemorales internii 1 and 2, between Ca. yacare and other crocodylians were found. We also discuss the muscle attachments that have different bony correlates among the crocodylian species and their morphological variation. Most of the correlates did not exhibit great variation among the species compared. The majority of the recognised correlates were identified in the pelvic girdle; additionally, some bony correlates associated with the pedal muscles are highlighted here for the first time. This research provides a wide framework for future studies on comparative anatomy and functional morphology, which could contribute to improving the character definition used in phylogenetic analyses and to understand the patterns of musculoskeletal hindlimb evolution.

Evaluation of the Association between Pelvic Diameters and Pelvic Types on Computed Tomography Images in Healthy Turkish Females / Evaluación de la Asociación entre Diámetros Pélvicos y Tipos de Pelvis en Imágenes de Tomografías Computarizadas en Mujeres Turcas Sanas

SUMMARY: Pelvis contributes to both human locomotion and obstetrics, and normal vaginal delivery is associated with a spacious inlet, a large interspinosus diameter. This paper aimed to measure crucial diameters of pelvic ring, and to determine both the prevalence of pelvic types, and labor types including normal vaginal delivery or caesarean section in Turkish healthy females. Additionally, it was aimed to evaluate presence of relationship between pelvic types and pelvic diameters. Labor shape of subjects was obtained from hospital records. This retrospective study was carried out on 165 healthy subjects aged between 18 and 45 years. Anteroposterior diameter of the pelvic inlet (APDI), anteroposterior diameter of the pelvic outlet, sacrum length (SL), sacrum depth, conjugata vera, obstetrical conjugate, the diagonal conjugate, diameter transversa, diameter bispinous, intertuberous diameter were measured. From these measurements, brim index was calculated and decided to gynecoid, anthropoid and platypelloid type. Also, the andoid type was calculated to the ratio of posterior sagittal diameter of the inlet to conjugata obstetrica. 50.91 % of participants has gynecoid type pelvis, followed by 24.85 % anthropoid type, 14.55 % platypelloid, and 9.70 % android type pelvis. There was a significant difference in APDI, SL, SD, Conjugata vera, Conjugata obstetrica, Conjugata diagonalis, Conjugata transversa, diameter bispinous, diameter intertubercularis and Brim index measurements according to pelvic types. the first degree of narrowing (conjugata vera from 11 to 9) was found in 18 pelvises and 12 pelvises with the pathological degree of narrowing bellonged to the platypelloid type followed by android type pelvis with 6 pelvices. The android type pelvis is not appropriate for natural labor and a good assessment of birth canal can reduce the labor risks. Also, only 7 females who delivered with cesarean have gynecoid type pelvic type. The APDI and SL were significantly lower in subjects having pathological narrowing according to conjugata obstetrica values.

La pelvis contribuye tanto a la locomoción humana como a la obstetricia. El parto vaginal normal se asocia con una entrada espaciosa y un diámetro interespinoso grande. Este artículo tuvo como objetivo medir diámetros cruciales del anillo pélvico y determinar tanto la prevalencia de los tipos pélvicos como los tipos de parto, incluido el parto vaginal normal o la cesárea en mujeres turcas sanas. Además, se buscó evaluar la presencia de relación entre los tipos de pelvis y los diámetros de la pelvis. La forma laboral de los sujetos se obtuvo de los registros hospitalarios. Este estudio retrospectivo se llevó a cabo en 165 mujeres sanas con edades comprendidas entre 18 y 45 años. Se midieron el diámetro anteroposterior de la entrada pélvica (APDPI), el diámetro anteroposterior de la salida pélvica, la longitud del sacro (SL), la profundidad del sacro, la conjugada vera, el conjugado obstétrico, el conjugado diagonal, el diámetro transverso, el diámetro biespinoso y el diámetro intertuberoso. A partir de estas mediciones se calculó el índice del ala y se decidió tipo ginecoide, antropoide y platipoide. Además, el tipo androide se calculó en función de la relación entre el diámetro sagital posterior de la entrada y la conjugada obstétrica. El 50,91 % de los participantes tenía pelvis de tipo ginecoide, seguida del 24,85 % de pelvis de tipo antropoide, el 14,55 % de tipo platipeloide y el 9,70 % de tipo androide. Hubo una diferencia significativa en las mediciones de APDPI, SL, SD, Conjugada vera, Conjugada obstétrica, Conjugada diagonal, Conjugata transversa, diámetro biespinoso, diámetro intertubercular e índice de ala según los tipos de pelvis. El primer grado de estrechamiento (conjugada vera del 11 al 9) se encontró en 18 pelvis y 12 pelvis, siendo el grado patológico de estrechamiento del tipo platipeloide seguido de pelvis tipo androide con 6 pelvis. La pelvis tipo androide no es apropiada para el parto natural y una buena evaluación del canal del parto puede reducir los riesgos. Además, solo 7 mujeres que dieron a luz por cesárea tenían un tipo pélvico de tipo ginecoides. El APDPI y SL fueron significativamente más bajos en mujeres que tenían estrechamiento patológico según los valores obstétricos conjugados.

Somatic and autonomic nerve density of the urethra, periurethral tissue, and anterior vaginal wall: an immunohistochemical study in adult female cadavers.

INTRODUCTION AND HYPOTHESIS: Retropubic procedures may disrupt nerves supplying the pelvic viscera; however, knowledge of pelvic neuroanatomy is limited. We sought to characterize somatic and autonomic nerve density within the urethra, periurethral tissue, and anterior vagina. METHODS: Axial sections were obtained from pelvic tissue harvested from female cadavers ≤24 h from death at three anatomical levels: the midurethra, proximal urethra, and upper trigone. Periurethral/perivesical tissue was divided into medial and lateral sections, and the anterior vagina into middle, medial, and lateral sections. Double immunofluorescent staining for beta III tubulin (ßIIIT), a global axonal marker, and myelin basic protein (MBP), a myelinated nerve marker, was performed. Threshold-based automatic image segmentation distinguished stained areas. Autonomic and somatic density were calculated as percentage of tissue stained with ßIIIT alone, and with ßIIIT and MBP respectively. Statistical comparisons were made using nonparametric Friedman tests. RESULTS: Six cadavers, aged 22-73, were examined. Overall, autonomic nerve density was highest at the midurethral level in the lateral and middle anterior vagina. Somatic density was highest in the external urethral sphincter (midurethra mean 0.15%, SD ±0.11; proximal urethra 0.19%, SD ±0.19). Comparison of annotated sections revealed significant differences in autonomic density among the lateral, medial, and middle vagina at the midurethra level (0.71%, SD ±0.48 vs 0.60%, SD ±0.48 vs 0.70%, SD ±0.63, p=0.03). Autonomic density was greater than somatic density in all sections. CONCLUSIONS: Autonomic and somatic nerves are diffusely distributed throughout the periurethral tissue and anterior vagina, with few significant differences in nerve density among sections analyzed. Minimizing tissue disruption near urethral skeletal muscle critical for urinary continence may prevent adverse postoperative urinary symptoms.

Beyond sex, gender, and other dilemmas: Human pelvic morphology from an integrative context.

Recent research on the pelvis has clarified the flexibility of pelvic bones to manage nearly infinite possibilities in terms of selection and drift, while still maintaining excellent bipedalism. Despite this work, and the studies outlining the diversity of pelvic morphology across the hominin lineage, conversations continue to be stymied by distractions related to purported trade-offs that the different functions the pelvis must either allow for (e.g., parturition) or directly perform (e.g., attachment sites of muscles). Here we show that tight constraints on morphology are not evident in the pelvic variation of multiple human populations. We thus provide further evidence that human pelves are not geometrically similar and that pelvic morphology successfully balances the intersection of population history, active selective, and drift.

Are vertebrates constrained to two sets of paired appendages? The morphology, development, and evolution of pre-pelvic claspers in the Holocephali.

Holocephalans exhibit auxiliary appendages called pre-pelvic claspers (PPCs) that are located anterior to the pelvic fins, while pelvic claspers are pelvic fin modifications located posteriorly as modified metapterygia. Articulation points of the PPCs have not previously been imaged or evaluated in a comparative context, therefore, they may represent modified pelvic fin structures if they articulate with the propterygium. Alternatively, they could represent the only example of an independent third set of paired appendages in an extant taxon, if they articulate independently from any pelvic fin basal cartilages, challenging the current paradigm that extant jawed vertebrates are constrained to two sets of paired appendages. Two extinct groups, including Placoderms and Acanthodians, exhibit variation in the number of paired appendages, suggesting this may be a plesiomorphic trait. We evaluated PPC developmental growth rates, morphology, and articulation points in spotted ratfish (Hydrolagus Colliei, Holocephali). We also compared variation in PPC morphology among representatives of the three extant holocephalan families. Both, the pre-pelvic and pelvic claspers exhibit a dramatic surge in growth at sexual maturity, and then level off, suggesting synchronous development via shared hormonal regulation. While mature females are larger than males, pelvic fin growth and development is faster in males, suggesting a selective advantage to larger fins with faster development. Finally, microcomputed tomography scans revealed that PPCs are not modified propterygia, nor do they articulate with the propterygium. They articulate with the anterior pre-pelvic process on the anterior puboischiadic bar (or pelvic girdle), suggesting that while they are associated with the pelvic girdle, they may indeed represent a third, independent set of paired appendages in extant holocephalans.

Pelvic shape change in adult Japanese macaques and implications for childbirth at old age.

Pelvic morphology exhibits a particular sexual dimorphism in humans, which reflects obstetrical constraints due to the tight fit between neonates and mothers. Huseynov et al. [Proc. Natl. Acad. Sci. U.S.A. 113, 5227-5232 (2016)] showed that in humans, pelvic sexual dimorphism is greatest around the age of highest fertility, and it becomes less marked in association with menopause in females. They proposed that this reflects changes of obstetrical versus locomotor functional demands in females. It remains unknown whether such developmental adjustment of the pelvic morphology is unique to humans. Macaques exhibit human-like cephalopelvic proportions, but they lack menopause and usually maintain fertility throughout adulthood. Here, we track pelvic development in Japanese macaques from neonate to advanced ages using computed tomography-based data. We show that female pelvic morphology changes throughout adult life, reaching the obstetrically most favorable shape at advanced ages rather than around primiparity. We hypothesize that pelvic morphology in Japanese macaques is developmentally adjusted to childbirth at advanced ages, where obstetrical risks are potentially higher than at younger ages. Our data contribute to the growing evidence that the female primate pelvis changes its morphology during the whole lifespan, possibly adjusting for changing functional demands during adulthood.

Changes in plasticity of the pelvic girdle from infancy to late adulthood in Homo sapiens.

Previous research on the effects of body mass on the pelvic girdle focused mostly on adult females and males. Because the ontogenetic plasticity level in the pelvis remains largely unknown, this study investigated how the association between body mass index (BMI) and pelvic shape changes during development. It also assessed how the large variation in pelvic shape could be explained by the number of live births in females. Data included CT scans of 308 humans from infancy to late adulthood with known age, sex, body mass, body stature, and the number of live births (for adult females). 3D reconstruction and geometric morphometrics was used to analyze pelvic shape. Multivariate regression showed a significant association between BMI and pelvic shape in young females and old males. The association between the number of live births and pelvic shape in females was not significant. Less plasticity in pelvic shape in adult females than during puberty, perhaps reflects adaptation to support the abdominopelvic organs and the fetus during pregnancy. Non-significant susceptibility to BMI in young males may reflect bone maturation accelerated by excessive body mass. Hormonal secretion and biomechanical loading associated with pregnancy may not have a long-term effect on the pelvic morphology of females.

Where is the optimal plane to mobilize the anterior rectal wall in female patients undergoing total mesorectal excision?

BACKGROUND: Since Heald proposed the total mesorectal excision (TME) procedure, the prognosis of patients with rectal cancer has been significantly improved. But Heald did not specifically describe the anterior surgical plane in female patients. And the surgical plane for mobilizing the anterior rectal wall during TME surgery in female patients remains controversial. AIM: To investigate the anatomy of the female pelvis and identify the optimal plane for mobilizing the anterior rectal wall. METHODS: We retrospectively collected surgical procedure videos and clinical data of female patients diagnosed with middle or low rectal cancer who underwent the TME procedure between January 2020 and October 2022 across six hospitals. The patients were divided into two groups based on the surgical approach used to mobilize the anterior rectal wall: The experimental group was to open the peritoneum at the lowest point of the peritonea reflection and enter the plane for mobilizing, while the control group was cut at 0.5-1 cm above the peritoneal reflection and enter another plan. Then, we compared the preoperative and postoperative information between the two groups. We also dissected and observed ten adult female pelvises to analyze the anatomic structure and compare the entry plane between the two approaches. Finally, we researched the pathological structure between the rectum and the vagina. RESULTS: Finally, 77 cases that met the criteria were included in our study. Our observations revealed that the experimental group underwent a smooth procedure, entering the plane amidst the mesorectal fascia and adventitia of the vagina, whereas the control group entered the plane between the vaginal adventitia and muscle layers. Compared to the control group, the experimental group showed a significant decrease in intraoperative bleeding [22.5 (19.5-50) mL vs 17 (5-20) mL, P = 0.01], as well as a shorter duration of hospitalization [9 (7-11.25) d vs 7 (6-10) d, P = 0.03]. Through the examination of surgical videos and cadaveric studies, we discovered that Denonvilliers' fascia is absent in females. Additionally, pathological sections further revealed the absence of Denonvilliers' fascia in females, with only loose connective tissue present between the mesorectal fascia and adventitia of the vagina. CONCLUSION: The plane amidst the mesorectal fascia and vaginal adventitia is the optimal surgical plane to mobilize the anterior rectal wall for female patients undergoing the TME procedure.