Vertebrae Research Articles

WGAN-based multi-structure segmentation of vertebral cross-section MRI using ResU-Net and clustered transformer

The vertebral foramen, lamina, and vertebral body are three critical components of the spine structure, essential for maintaining spinal connectivity and stability. Accurately segmenting lumbar structures such as the vertebral body, vertebral foramen, and lamina in MRI cross-sections helps doctors better understand and diagnose the pathological causes of spine-related diseases. This study presents a multi-structure semantic segmentation method for vertebral transverse section MRI slices using WGAN with a residual U-Net and clustered Transformer. The generator network was replaced with a combination of a residual U-Net and a clustered Transformer-based segmentation network. The enhanced U-Net encoder, utilizing dilated convolutions and residual structures, improved multi-scale feature extraction capabilities. Meanwhile, the clustered Transformer structure, with reduced progressive linear complexity, ensured the extraction of global positional information. The results of multiple experiments show that the Dice coefficient for vertebral body segmentation increased by 3.1%, the Hausdorff distance decreased by 0.6 mm, mIOU improved by 4.1–96.2%, and PPV increased by 2.0–98.8% compared to mainstream segmentation models. These improvements are statistically significant (p < 0.05).Ablation experiments further validated the effectiveness of the proposed enhanced modules in improving segmentation accuracy for the three target structures.

A new ankylosaurid dinosaur from the Upper Cretaceous of Jiangxi Province, southern China

ABSTRACT Huaxiazhoulong shouwen gen. et sp. nov. is a new ankylosaurid recovered from the Upper Cretaceous Tangbian Formation of Jiangxi Province, southern China. Huaxiazhoulong shouwen can be diagnosed on the basis of three autapomorphies (the middle shaft and distal end of the ischium are expanded; the ratio of width of distal end to minimum shaft width is greater than 3 in humerus, the maximum length of femur to humerus length ratio is about 1.45) and a unique combination of characters (the centra of anterior caudal vertebrae in anterior view is heart-shaped; the dorsal surface of scapula is straight; the scapulocoracoid has a large medial brace; the humeral head and deltopectoral crest are separated by a distinct notch anteriorly). The phylogenetic analysis shows that Huaxiazhoulong shouwen is an early member of Ankylosauridae.

Dental Pulp Stem Cell Conditioned Medium Enhance Osteoblastic Differentiation and Bone Regeneration.

Cell-free approaches, utilizing mesenchymal stem cell secretome, have promising prospects in various fields of regenerative medicine. In this study, we examined in vitro and in vivo the potential of dental pulp stem cell-conditioned medium (DPSC-CM) for bone regeneration. The secretome of undifferentiated stem cells from dental pulp were collected, and the effects of this DPSC-CM were assessed for osteodifferentiation of osteoblast-like cells (MG-63) and osteoblasts deriving from DPSC. Cell proliferation, alkaline phosphatase (ALP) activity, gene expression of Runt-related transcription factor 2 (Runx2), Bone Sialoprotein (BSP), Osteocalcin (OCN), and extracellular matrix mineralization were evaluated. The rat caudal vertebrae critical size defect model was to investigate the effect of DPSC-CM in vivo. Results showed that DPSC-CM induced cell growth, and increased ALP activity and the expression of key marker genes at an early stage of osteoblastic differentiation compared to control. A rat bone defect model was used to illustrate the effect of DPSC-CM in vivo. The bone density within the defects were improved using conditioned medium, even though there was no significant difference between the control and DPSC-CM groups. The analysis of DPSC-CM by human growth factor antibody array revealed the presence of several factors involved in osteogenesis. Taken together, these findings indicate that DPSC-CM is a promising therapeutic candidate for bone regenerative therapy, accelerating the maturation of osteoblastic cells. And even though safety and efficiency of DPSC-CM have to be confirmed in preclinical studies, these results represent a first step toward clinical application.

New evidence for the presence of carcharodontosaurid theropod dinosaurs in the Late Cretaceous of Uzbekistan

ABSTRACT An incomplete posterior dorsal vertebra ZIN PH 2646/16 from the Upper Cretaceous (Turonian) Bissekty Formation of Uzbekistan has a highly pneumatized centrum and neural arch. The centrum has a lateral pneumatic foramen that is divided by a septum. The neural arch is invaded through a lateral pneumatic foramen above the neurocentral suture and has deeply excavated prezygapophyseal-centrodiapophyseal and centrodiapophyseal fossae. The interior of the preserved portion of the neural spine is pneumatic. In the structure of the fossae on the neural arch and the presence of a double pneumatic foramen on the centrum, ZIN PH 2646/16 closely resembles the carcharodontosaurid Acrocanthosaurus from the Early Cretaceous of North America. Thus, we identify ZIN PH 2646/16 as Carcharodontosauridae indet. Carcharodontosauridae were previously known from the Bissekty Formation from Ulughbegsaurus uzbekistanensis, which is based on an incomplete maxilla.

Analgesic Effect of Conventional Paravertebral versus Mid transverse Process to Pleura Blocks on Post Mastectomy Pain in Unilateral Modified Radical Mastectomy Surgeries

Analgesic Effect of Conventional Paravertebral versus Mid transverse Process to Pleura Blocks on Post Mastectomy Pain in Unilateral Modified Radical Mastectomy Surgeries

The Effect of L5 Morphology on Prevention of L5-S1 Degeneration Following Floating Fusion for Degenerative Spine Disorders.

Retrospective Study. The selection of floating fusion or lumbosacral fusion arises when treating patients with instability or stenosis of the lower lumbar spine concomitantly radiographic degeneration of L5-S1. This study aimed to investigate the preoperative anatomical or morphological factors affecting the survivorship of the L5-S1 after floating fusion. This study included 77 patients who had undergone floating fusion surgery through the TLIF approach. Preoperative radiographic parameters were evaluated using anteroposterior and lateral lumbar spine radiographs. The patients were divided into two groups according to the Modified Pfirrmann Grading and total endplate score. Multivariable regression analysis was performed to explore the relationships between the anatomical or morphological characteristics of L5 and the degeneration of L5-S1. The disc degeneration group exhibited a smaller height ratio of the iliac crest (Hi) and a less L5 deep position. Furthermore, the right/left height of L4 (Hr/Hl) and the right/left width of transverse process of L5 (CRt/CLt) were significantly higher in the disc and endplate degeneration groups. Multiple logistic regression analysis revealed that Hi and CRt were independently associated with L5-S1 disc degeneration, whereas Hr was a significant risk factor for L5-S1 endplate degeneration. Anatomical and morphological characteristics of L5, such as smaller Hi, higher CRt and Hr, were associated with an increased risk of L5-S1 degeneration in patients after floating fusion. These findings may indicate the fusion level when addressing lower lumbar degenerative diseases and the concurrent radiographic degeneration of L5-S1.

What can be observed in intervertebral cartilage endplate with aging? An animal model study of excessive axial mechanical loading

IntroductionThe cartilage endplate (CEP) plays a crucial role as both a mechanical barrier and nutrient channel for the intervertebral disc, but it is vulnerable to excessive axial loading. We modified the Ilizarov external fixator and applied it to the CEP of the rat tail to impose diurnal, controllable excess axial loading. The objective was to measure morphological changes in the CEP when subjected to loading during the aging process.MethodsTwo Kirschner wires were, respectively, inserted into the center of the eighth and ninth coccygeal vertebrae (Co8/9) of rat (n = 54) to apply axial loading to the CEP. A remote control device was used to establish the diurnal loading schedule. At the end of 4, 8, and 12-week periods, the Co8/9 CEPs in each group were analyzed using MRI, histological staining, and immunohistochemical staining techniques.ResultsThe novel Ilizarov model that we modified successfully induced degeneration of the rat coccygeal CEP. MRI analysis revealed significant degenerative changes in the loaded Co8/9 CEP, including decreased signal intensity and the formation of Schmorl’s nodes at 8 and 12 weeks. Histological examination showed progressive CEP degeneration (CEPD), characterized by decreased microporosity, thinning, and structural irregularities. Immunohistochemical analysis demonstrated a significant reduction in Aggrecan and Collagen II expression in the CEP and nucleus pulposus over time. Control and sham groups maintained normal CEP structure and composition throughout the study period.ConclusionExcessive axial loading induced CEPD in the rat tail, primarily characterized by the formation of Schmorl’s nodes and a reduction in CEP microporosity in this study. Our modified Ilizarov rat tail compression model, featuring stable and controllable axial loading capabilities, provided an alternative experimental paradigm for further investigation into CEPD.

Evaluation of Radiological and Anatomical Features of Cervical Vertebrae in Adult Persian Cat.

Radiographic studies of Persian cat's cervical vertebrae can provide us with valuable information used in identifying its anatomical features, investigating various species of Persian cats and evaluating their cervical pathologies. The present study aimed to investigate the anatomical and radiological features of cervical vertebrae in Persian cats to create a comprehensive and accurate reference for the normal range of cervical bones and joints that can be used for clinical decision-making and interpretation of radiographic findings in these cats. The present descriptive-cross-sectional study included 10 adult Persian cats, including 5 males and 5 females. All cats underwent radiography in the dorsoventral, ventrodorsal, left lateral and right lateral recumbency. Then, anatomical investigations were performed. According to our findings, Persian cats were different from other cat species in some cervical vertebral characteristics, which can be suggested as comparative anatomy in these species. The most important differences were as follows: the C3 and C7 had the lowest and highest spinous process height (SPH), respectively. The atlas had the highest transverse process width (TPW), which was significantly different with other cervical vertebrae (p ≤ 0.05). Moreover, the cervical vertebrae were not significantly different in vertical diameter of cranial vertebral foramen (VDCrVF) and transverse diameter of cranial vertebral foramen (TDCrVF) (p ≤ 0.05). The caudal surface of the atlantic vertebral arch had two dorsal and ventral tubercles. Also, the ventral crest of the axis was quite indistinct in the cranial part while becoming prominent in the caudal part. The C3 spinous process was a wide, small tubercle, while the C7 spinous process was extended vertically. Finally, the C6 transverse processes had a large ventrocranial tubercle forming a sagittal plate with cranial and caudal parts separated by a notch. The accurate and comprehensive standard ranges obtained from the present study can be used for the interpretation of imaging results, clinical decision-making, and finding the normal and abnormal sizes of the cervical vertebrae and their processes in Persian cats.

Ultrasound-guided quadratus lumborum block with 0.5 mL of 0.2% bupivacaine/kg is a valuable perioperative analgesic adjunct for cats undergoing ovariectomy.

To assess the perioperative analgesic effects of bilateral ultrasound (US)-guided quadratus lumborum block (QLB) using low-volume (LV) or high-volume (HV) bupivacaine, compared to a control group, in cats undergoing ovariectomy. 48 healthy female cats. Cats were sedated with IM dexmedetomidine (5 µg/kg), ketamine (1 mg/kg), and methadone (0.2 mg/kg) followed by IV propofol induction and isoflurane maintenance. Cats were randomly assigned to 3 groups of 16 patients each: QLB-LV group (0.3 mL/kg/side), QLB-HV group (0.5 mL/kg/side), and control group (no QLB). Bilateral, in-plane, US-guided QLB was performed with lateral approach at the L2 transverse process with bupivacaine 0.2%. Physiological variables were recorded intraoperatively by a masked investigator. If intraoperative nociception occurred, fentanyl (1 µg/kg) was administered IV. Rescue postoperative analgesia (buprenorphine, 0.2 mg/kg) was administered in case of a Feline Grimace Scale score ≥ 4 after a 4-hour evaluation period. In the control group, heart rate (HR) was higher than the QLB-LV group during the first ovarian manipulation (P < .001) and higher than the QLB-HV group during both ovarian manipulations (P < .001 and P = .006). The need for intraoperative rescue analgesia and postoperative pain scores were significantly higher in the QLB-LV (P = .005 and P = .047) and control (P < .001 and P < .001) groups compared to the QLB-HV group. Buprenorphine was administered once in the control group. No clinical signs of bupivacaine toxicity or QLB complications were observed. Bilateral US-guided QLB-HV may effectively provide perioperative analgesia in feline patients undergoing ovariectomy.

Covariation in the Craniocervical Junction of Carnivora.

The craniocervical junction is the transition between the skull and the vertebral column that provides mobility while maintaining sufficient stability (i.e., protection of the brainstem and the spinal cord). The key elements involved are the occiput, the first cervical vertebra (CV1, atlas) and the second cervical vertebra (CV2, axis). The two vertebrae forming the atlas-axis complex are distinct in their morphology and differences in form have been linked to differences in ecological function in mammals. Here, we quantified the morphological diversity of the cranium, CV1 and CV2 in a sample of Carnivora using 3D geometric morphometrics to reveal phylogenetic and ecological patterns. Our results indicate that the observed variation in CV2 is related to the taxonomic diversity (i.e., strong phylogenetic signal), whereas variation in CV1 appears to be decoupled from species diversity in Carnivora and, thus, is likely to reflect a functional signal. The phylogenetically informed correlation analyses showed an association between the CV1 morphology and diet. Taxa that primarily feed on large prey tend to have larger transverse processes on CV1 which provides larger muscle attachment areas and may correlate with stronger muscles. The latter needs to be verified by future quantitative covariation analyses between bone and muscle data. Morphological peculiarities within Pinnipedia and Mustelidae could be explained by differences in terrestrial locomotion between Phocidae and Otariidae and the exceptional defensive behavior (i.e., handstanding) in Mephitidae. Despite differences in the degree of morphological diversity, covariation between cranium, CV1 and CV2 morphology is consistently high (≥ 0.82) highlighting that overall, the craniocervical junction is an integrated structure, but there are traits that are not constrained.

Hydatid disease contributes to spinal cord compression: a case report and literature review

BackgroundHydatid disease is an infectious disease caused by echinococcus that causes liver and lung damage in humans. Bone involvement is rare and accounts for only 0.5%-4% of hydatid diseases; the spine is more prone to be infected with a proportion of 50% in musculoskeletal tissue. Missed hydatid cysts may lead to serious consequence, it is necessary to diagnosis and treatment of hydatid cysts at early stage.Case presentationWe present a case of a 47-year-old Han Chinese male diagnosed with spinal hydatidosis. The patient lived in pasturing areas accompanied by symptoms of low back pain radiating to the legs, progressive weakness, and hypoesthesia in the lower limbs accompanied by difficulty walking. Computed tomography (CT) images showed a spinal hydatid cyst in the lumbar vertebra2 (L2) that caused bone destruction in the vertebral body and lamina. Magnetic resonance imaging (MRI) images showed hyperintense cystic components on L2 with the appearance of a lobulated, multiocular, septate cystic mass and compression of the spinal cord at the segments of L2. The patient underwent subtotal vertebral resection to completely remove the damaged vertebral and paravertebral cysts, and histopathological examination revealed the characteristic features of hydatid cysts. The patient received a postoperative antiparasitic drug treatment and finally achieved a successful treatment.ConclusionsSpinal hydatidosis is a rare infectious disease. It should be considered as an important differential diagnosis for patients accompanying by spinal bone destruction with animal contact history. Surgical removal combined with antiviral drugs is an effective way to treat spinal hydatidosis. In addition, long term follow-up is mandatory for avoiding its recurrence.

Biomechanical Analysis and Modeling of Different Traction Patterns in Adolescent Idiopathic Scoliosis

Objective: Traction is a valuable treatment for Adolescent idiopathic scoliosis; however, assessing its biomechanical effects, particularly with new methods, presents challenges. This study aims to explore the biomechanics using finite element analysis, with the goal of enhancing safety and effectiveness. Methods: Based on CT images, two different boundary and loads were applied to simulate two traction methods. The effects of these two traction methods on stress and deformation of lumbar vertebral bodies and intervertebral discs were compared. Results: Under two traction methods, the stress was concentrated on the posterior side. Multi-point traction resulted in higher stress and deformation, and concentrated stress on the convex side as well. However, there is some stress concentration on the vertebral arch, which may lead to injury. Conclusion: Compared to longitudinal traction, multi-point traction can better reduce stress on the vertebral bodies and intervertebral discs, focusing the pulling force on the concave side and achieving greater deformation. Multi-point traction might better suit specific patients needing more correction and pressure relief compared to longitudinal traction.

Experience of using the passive exoskeleton EXAR-34 in complex rehabilitation of a patient with post-traumatic plexopathy due to gunshot cervicothoracic wound (clinical observation)

The use of passive exoskeletons is a promising direction in the treatment of patients with severe combat injuries to the shoulder girdle, leading to disability in 30 % of cases. Aim: To demonstrate the capabilities of the passive exoskeleton EXAR-34 in the rehabilitation and habilitation of a victim with damage to the branches of the brachial nerve plexus. Materials and methods: An analysis of medical documentation, physical examination, morphometry, and goniometry were carried out. Clinical observation and discussion: A patient with post-traumatic left-sided plexopathy due to a gunshot perforating shrapnel cervicothoracic wound with gunshot fractures of the transverse processes of C6, C7, Th3 vertebrae, I–III ribs on the left after reconstructive intervention on elements of the brachial nerve plexus, when previously carried out rehabilitation measures were ineffective, during the first fitting of the EXAR-34 device, the range of active movements in the joints of the injured limb increased to 37,1–60,7 %, and routine motor skills were restored. Conclusion:The experience of using the EXAR-34 device demonstrates high promise in complex rehabilitation and habilitation of patients after reconstructive interventions on the brachial plexus for combat wounds.

Cellular and molecular mechanisms that shape the development and evolution of tail vertebral proportion in mice and jerboas.

Despite the functional importance of the vertebral skeleton, little is known about how individual vertebrae elongate or achieve disproportionate lengths as in the giraffe neck. Rodent tails are an abundantly diverse and more tractable system to understand mechanisms of vertebral growth and proportion. In many rodents, disproportionately long mid-tail vertebrae form a 'crescendo-decrescendo' of lengths in the tail series. In bipedal jerboas, these vertebrae grow exceptionally long such that the adult tail is 1.5x the length of a mouse tail, relative to body length, with four fewer vertebrae. How do vertebrae with the same regional identity elongate differently from their neighbors to establish and diversify adult proportion? Here, we find that vertebral lengths are largely determined by differences in growth cartilage height and the number of cells progressing through endochondral ossification. Hypertrophic chondrocyte size, a major contributor to differential elongation in mammal limb bones, differs only in the longest jerboa mid-tail vertebrae where they are exceptionally large. To uncover candidate molecular mechanisms of disproportionate vertebral growth, we performed intersectional RNA-Seq of mouse and jerboa tail vertebrae with similar and disproportionate elongation rates. Many regulators of posterior axial identity and endochondral elongation are disproportionately differentially expressed in jerboa vertebrae. Among these, the inhibitory natriuretic peptide receptor C (NPR3) appears in multiple studies of rodent and human skeletal proportion suggesting it refines local growth rates broadly in the skeleton and broadly in mammals. Consistent with this hypothesis, NPR3 loss of function mice have abnormal tail and limb proportions. Therefore, in addition to genetic components of the complex process of vertebral evolution, these studies reveal fundamental mechanisms of skeletal growth and proportion.

Morphological Changes in the Lumbar and Abdominal Muscles in Individuals with Sacralization

Although sacralization is one of the most common congenital anomalies of the spine, its effect on surrounding muscles is still not well known. This study was conducted to determine the size of the lumbar and abdominal muscles of the individuals with sacralization and to compare with the control group. Eighty-five participants with sacralization phenomena and fifty-six asymptomatic participants were included in this study. Sacralization was classified according to the Castellvi classification. The cross-sectional area of the multifidus lumborum, erector spinae and rectus abdominis muscles, and the section thicknesses of external abdominal oblique, internal abdominal oblique and transversus abdominis muscles were measured bilaterally on axial computed tomography images at the L1-2 and L4-5 levels. ANCOVA revealed that there is no any significant group*side interaction effect regarding muscles sizes in terms of two groups in L1-L2 and L4-L5. In addition, ANCOVA revealed a both side effect [(p=.020; η2p=.038)] and group*side interaction effect [(p=.010; η2p=.049)] regarding length of the L5 transverse process (p˃.05). Regardless of low back pain, muscle sizes are not associated with the sacralization phenomenon.

Morphometry of Typical Cervical Vertebrae on Magnetic Resonance Imaging in Adult Bangladeshi People: A Cross-sectional Analytical Study

Background: Accurate knowledge of cervical vertebral morphometry is crucial for diagnosing pathological conditions and planning surgical interventions. However, data specific to the Bangladeshi population is lacking. Objectives: To determine the morphometric measurements of typical cervical vertebrae (C3-C6) on Magnetic Resonance Imaging (MRI) in adult Bangladeshi people and to analyze potential sex-based differences. Methods: This cross-sectional analytical study was conducted on 70 MRI scans (35 male, 35 female) of typical cervical vertebrae from adult Bangladeshi individuals. Various morphometric parameters were measured using 'Radiant DICOM Viewer' software. Statistical analysis was performed using SPSS version 22.0. Results: The sagittal diameter of the vertebral body was significantly larger in males compared to females for all measured vertebrae (p&lt;0.001). No significant differences were found between sexes in the height and transverse length of the vertebral body, anteroposterior and transverse lengths of the vertebral foramen, dimensions of foramen transversarium, superior articular facets, lamina, pedicle, and spinous process length (p&gt;0.05 for all). Conclusion: This study provides baseline morphometric data for typical cervical vertebrae in adult Bangladeshi individuals. The observed sexual dimorphism in sagittal vertebral body diameter and the lack of significant differences in other parameters contribute to our understanding of population-specific cervical spine anatomy. These findings may have implications for optimizing surgical techniques and implant designs for the Bangladeshi population.

Oral pharmacological management of Bertolotti syndrome presenting as chronic low back pain – A case report and review of literature

BackgroundBertolotti syndrome (BS) is often a missed cause of chronic lower back pain in young individuals, commonly associated with the presence of anomalous lumbosacral transitional vertebrae. Case presentationA 19-year-old female with no significant medical or family history presented with persistent lower back pain localized to the gluteal region and posterolateral aspect of the left lower back. The pain worsened over time and limited their movements, including walking. A Ferguson radiograph revealed fusion of the left transverse process of the L5 vertebral segment with the left sacral ala. History, examination findings, and radiological workup confirmed the diagnosis of BS. The patient preferred conservative management, receiving oral pharmacological therapy for six weeks, along with education on preventive measures and routine exercises for postural stability. At a six-month follow-up, the patient remained asymptomatic and managed well. ConclusionsConservative oral pharmacological treatment presents a unique and viable alternative to traditional methods for managing BS, which often involve surgery or steroids/anesthetics at the pseudo-articulation site. Given that BS is common yet underdiagnosed in young patients with chronic back pain, this report also underscores the importance of including it in differential diagnoses for chronic lower back pain in this demographic.

Heritability in the Rhesus Macaque (Macaca mulatta) Vertebral Column.

The vertebral column plays a central role in primate locomotion and positional behavior. Understanding its evolution, therefore, has the potential to clarify evolutionary processes that have occurred in the primate lineage as well as the specific behaviors of extinct primates. However, to understand primate vertebral anatomy, it is important to determine how much of this anatomy is heritable and how much develops as a response to environmental factors during life. We estimated heritability for vertebral counts as well as typical cervical, thoracic, and lumbar elements from 210 individuals from the pedigreed Cayo Santiago Macaca mulatta skeletal collection. We found moderate heritability of vertebral counts (h2 = 0.216-0.326), but with strong heritability of the type of variation (e.g., a tendency to meristic or homeotic change) in the vertebral count (h2 = 0.599), suggesting a possible explanation for high variability in vertebral numbers among the hominoids in particular. The moderate heritability of vertebral count also suggests that vertebral count is an unsuitable metric for estimating the ancestral state for some taxa. We found strong heritability in the morphology of cervical and upper lumbar zygapophyseal facets (h2 = 0.548-0.550) and the thoracic spinous processes (h2 = 0.609-0.761), including high heritability of the spinous process angle in the upper thoracic and upper lumbar elements (h2 = 0.649-0.752). We suggest these are related to maintaining stability in the cervical and lumbar regions, and reducing motion in the thoracic region, respectively. We propose that spinous processes may contain greater phylogenetic information, whereas transverse processes may contain greater information of function 'in life'. We also found important size effects, suggesting that size is the most heritable component of overall form and largely responsible for intertrait differences. This suggests that it is inappropriate to indiscriminately remove size effects from morphological comparisons.

Approach to frontal sinus via five frontal sinus drainage pathways.

This study aimed to validate a method for successful frontal sinus surgery. The method classifies the frontal sinus drainage pathway (FSDP) into five categories based on three bony walls of the anterior ethmoid sinus, including the uncinate process (UP), accessory uncinate process (UPa), and basal lamella of the ethmoid bulla (BLEB), which was tested in actual surgical procedures. This study analyzed 53 sides of 48 patients who underwent frontal sinus surgery between October 2022 and March 2023. We classified the FSDPs using preoperative computed tomography (CT) and multiplanar reconstruction (MPR). During surgeries for FSDPs located anterior to the BLEB, we used a two-step method involving resection of the turbinal UP, followed by upward resection from the lower edge of the ethmoidal UP. For FSDPs located posterior to the BLEB, we resected the BLEB at the superior semilunar recess. We confirmed the origin of each of the five types of FSDP during surgery. These origins, which were located at the lowest part of the anterior ethmoid, could be identified in the early stages of ethmoid sinus surgery before proceeding to the frontal recess area. The origins of the five types of FSDP, classified based on the bony walls, can be clearly and accurately identified during surgery. This provides a reliable method for preoperatively predicting and locating the inferior end of the FSDP (origin), without extensive manipulation of the cells formed in the frontal fossa.

African cichlid fishes: morphological data and taxonomic insights from a genus-level survey of supraneurals, pterygiophores, and vertebral counts (Ovalentaria, Blenniiformes, Cichlidae, Pseudocrenilabrinae).

The iconic freshwater cichlid fishes (Cichlidae) comprise about 1750 validly named species and hundreds more that are known, but not yet described and named. Cichlids are an important source of protein for millions of people on several continents, are model organisms in studies of evolution, speciation, ecology, development, behaviour and physiology and are popular as aquarium fishes. Yet, comparative studies of cichlid internal anatomy are rare. Even their osteology has not been taxonomically surveyed. The cichlid postcranial skeleton has been especially neglected. Here, I provide the first survey in cichlids of the considerable variation in numbers of vertebrae, supraneurals and dorsal- and anal-fin supports (pterygiophores), as well as the patterns with which the pterygiophores insert between the neural or haemal spines. The study includes some 1700 specimens of nearly 400 cichlid species. Focusing on the largest subfamily, the African cichlids or Pseudocrenilabrinae, the survey furnishes data from species in all but one of its 166 genera. Limited data from species in the other cichlid subfamilies (Etroplinae, Ptychochrominae and Cichlinae) and from the related leaffishes, Polycentridae, are also presented. Key examples of pterygiophore insertion patterns from throughout the range of variation are illustrated and discussed. Detailed analytical tables and all raw data are provided in supplementary files.A bizarre specialisation in Cyprichromis is noted, evidently for the first time. Uniquely in this Lake Tanganyikan genus, five to seven anal pterygiophores are abdominal in position, located anterior to the anal fin and inserting toward or between successive pairs of pleural ribs.Taxonomic changes: The most speciose tribe of African cichlids, currently known as Haplochromini, is correctly called Pseudocrenilabrini. Based chiefly on the molecular phylogenetic findings of other workers, I propose four pseudocrenilabrine subtribes, one occurring in rivers and three endemic to Lake Malawi. I also re-assign the Lake Tanganyikan tribe Tropheini as another subtribe of Pseudocrenilabrini, in line with numerous molecular studies placing tropheines firmly within this tribe. The remaining genera of Pseudocrenilabrini remain incertae sedis in this tribe pending clarification of their phylogenetic relationships.The character complex here surveyed is a promising source of taxonomically and phylogenetically informative characteristics distinguishing or uniting cichlid taxa at multiple hierarchical levels, from species through subfamily. This reference set of novel character data can also provide information for palaeontological studies of African cichlids. These attributes are skeletal features potentially available for study in well preserved fossils and may help determine their correct taxonomic placement.