Comparative Anatomical Study Research Articles

Common animal models lack a distinct glenoid labrum: a comparative anatomy study

PurposeDevelopment and validation of an animal model of labral healing would facilitate translation of novel surgical and biological strategies to improve glenolabral healing. The purpose of this study was to characterize the anatomic and histological properties of the shoulder labrum in rat, rabbit, dog, pig, goat, and humans. Given the demonstrated similarities in size and structural morphology in other joints, it was hypothesized that the goat glenoid with surrounding capsulolabral complex would most closely resemble that of humans in terms of dimensions and structure, as observed grossly and histologically.MethodsCadaveric glenohumeral joints from rats (n = 8), New Zealand white rabbits (n = 13), Mongrel dogs (n = 9), Spanish goats (n = 10), Yorkshire pigs (n = 10), and humans (n = 9) were freshly harvested. Photographs were taken of the glenoid with its surrounding capsulolabral complex. Linear dimensions of the glenoid articular surface were measured. It was determined where the capsulolabral complex was continuous with, or recessed from, the articular glenoid surface. The glenoid was divided into 6 equal segments radiating out toward 12, 2, 4, 6, 8, and 10 o’clock positions. Samples were sectioned and stained with Safranin O/Fast green and Mallory Trichrome. Insertion of the capsulolabral tissue onto the glenoid was qualitatively assessed and compared with gross morphology.ResultsDimensions of the goat glenoid most closely paralleled dimensions of the human glenoid. A capsulolabral complex was continuous with the glenoid surface from ~ 9 to 12 o’clock in the rats, 7 to 12 o’clock in rabbits, 5 to 12 o’clock in the dogs, and 9 to 12 o’clock in goats, 6 to 12 o’clock in pigs, and 2 to 8 o’clock in humans. In contrast to humans, no other species demonstrated an organized fibrocartilaginous labrum either macroscopically or histologically.ConclusionThe animals in the present study did not possess a discrete fibrocartilaginous labrum by gross or histological evaluation, as directly compared to humans. While models using these animals may be acceptable for examining other shoulder pathologies, they are not adequate to evaluate labral pathology.Level of evidenceBasic Science Study; Anatomy and Histology; Cadaveric Animal Model.

Planarian Anatomy Ontology: a resource to connect data within and across experimental platforms.

ABSTRACTAs the planarian research community expands, the need for an interoperable data organization framework for tool building has become increasingly apparent. Such software would streamline data annotation and enhance cross-platform and cross-species searchability. We created the Planarian Anatomy Ontology (PLANA), an extendable relational framework of defined Schmidtea mediterranea (Smed) anatomical terms used in the field. At publication, PLANA contains over 850 terms describing Smed anatomy from subcellular to system levels across all life cycle stages, in intact animals and regenerating body fragments. Terms from other anatomy ontologies were imported into PLANA to promote interoperability and comparative anatomy studies. To demonstrate the utility of PLANA as a tool for data curation, we created resources for planarian embryogenesis, including a staging series and molecular fate-mapping atlas, and the Planarian Anatomy Gene Expression database, which allows retrieval of a variety of published transcript/gene expression data associated with PLANA terms. As an open-source tool built using FAIR (findable, accessible, interoperable, reproducible) principles, our strategy for continued curation and versioning of PLANA also provides a platform for community-led growth and evolution of this resource.

BelinurusBronn, 1839 (Chelicerata, Xiphosura) has priority overBellinurusPictet, 1846

In the first half of the nineteenth century, a marked shift occurred in our understanding and treatment of the chelicerate fossil record, with the differentiation and recognition of entirely extinct genera for the first time. At the heart of this taxonomic revolution were the Eurypterida (sea scorpions) and Xiphosura (horseshoe crabs), although both groups were in fact considered crustaceans until Lankester's (1881) seminal comparative anatomical study of the extant xiphosuranLimulusMüller, 1785 and modern scorpions. The oldest available eurypterid genus isEurypterusdeKay, 1825; the oldest available fossil arachnid genus name is that of the scorpionCyclophthalmusCorda, 1835. However, there has been considerable historical confusion over the oldest available fossil xiphosuran genus name, which has been recognized alternately asBelinurusKönig (with a publication date of either 1820 or 1851) or the synonymousBellinurusPictet, 1846. Most recent treatments (e.g., Selden and Siveter, 1987; Anderson and Selden, 1997; Anderson et al., 1997; Lamsdell, 2016, 2021; Bicknell and Pates, 2020) have favoredBellinurusPictet, 1846 as the available name; however, Haug and Haug (2020) recently argued thatBelinurusKönig, 1820 is valid and has priority, a position then followed by Lamsdell (2020), prompting a reinvestigation of the taxonomic history of the genus. Upon review, it is clear that neither of the previously recognized authorities forBelinurusare accurate and that the two candidate type species for each genus are, in fact, synonyms. Given the convoluted and at times almost illogical history of the competing names, along with the most recent controversy as to which has priority, we present a complete history of the treatment of the genus to resolve the issue.

Iatrogenic Damage to Neurovascular and Soft Tissue Structures During Lateral Release of Hallux Valgus: A Comparative Anatomical Study of Minimally Invasive Versus Open Surgical Techniques

Lateral release is often an integral step in surgical correction of hallux valgus and can be performed using open or minimally invasive techniques. We investigated whether these techniques cause iatrogenic damage to arteries, nerves, tendons, or joint capsules. In this cadaver study, lateral release was performed on 9 pairs of specimens by a specialized foot surgeon. The specimens were randomly assigned to each group. The operations were followed by anatomical preparation, data collection, photo documentation, and statistical analysis. Iatrogenic damage to arteries, nerves, tendons, or joint capsules was rare, regardless of the surgical technique used. However, with the minimally invasive technique, the tendon of the extensor hallucis longus muscle and the sensitive terminal branches of the fibular nerve were at risk due to their anatomical proximity to the access portal. The deep transverse metatarsal ligament was potentially at risk if the adductor hallucis muscle was completely detached from the lateral sesamoid. When the deep transverse metatarsal ligament was transected there was risk of damaging the underlying plantar neurovascular structures. Both surgical techniques are safe in terms of the risk of injury to neighboring neurovascular and soft tissue structures.

Gross Anatomical Studies on the Hind Limb of the West African Giraffe (Giraffa camelopardalis peralta).

This study on the gross anatomy of the West African giraffe's hind limb was aimed at investigating the unique morphological features and number of bones making up this region of the skeleton. Two (2) adults obtained as carcasses at different times after postmortem examination were prepared to extract the bones via cold water maceration for use in the study. The appearance of the ossa coxarum and its features presented similarities to that of the horse. However, differences were evident in the convex cranial border of the ilium, small less prominent coxal tuber, and wider interval between the opposite sacral tuber and an oval obturator foramen. Common features reported in most species such as the gluteal line and psoas tubercle were absent. The long femur presented proximally; the greater trochanter connected obliquely via the trochanteric crest to the lesser trochanter. The supracondyloid fossa, obliquely directed medial condyle, and trochlea with two unequal ridges were presented distally. The fibula was absent while the tibia was typical of ruminant presentation with one popliteal line and no muscular lines on its caudal surface. The five (5) tarsals were arranged three proximally and two distally. One (1) metatarsal (3rd and 4th fused) presented two condyles that anchor two (2) digits with 3 phalanges and 3 sesamoid bones each. The total number of bones making up the hind limb was accounted to be 45. In conclusion, this study has provided a baseline data for further biological, archeological, and comparative anatomical studies.

Comparative study of root, stem, and leaf anatomy of young Sogdian ash trees (Fraxinus sogdiana Bunge) growing in river valleys of the Sharyn State National Park

The study of endangered relict woody plants is a key component of biodiversity conservation strategies. In this regard, the purpose of the study was to compare anatomical features of the vegetative organs of relict Sogdian ash (Fraxinus sogdiana Bunge) growing in river valleys of the Sharyn State National Park in the Almaty region. In 2020-2021 young individuals of Sogdian ash were sampled, in the valleys of the Sharyn and Temirlik rivers to study, their root, stem, and leaf anatomical features for the first time. The lower and upper epidermis of F. sogdiana leaves were thicker in individuals growing at the Sharyn site than at the Temirlik site. In contrast to that, the thickness of the mesophyll was thicker in leaves from the Temirlik site. The cross-sectional area of the conductive bundles of plants were larger in trees from the Sharyn site. The morphometric parameters of the stem also had different results. The diameter of the roots were twice as large in Sogdian ash trees growing at the Sharyn site, likely due to the growing conditions, since the soil of the Sharyn River valley is meadow, stony and pebbly, compared to the Temirlik River, which is a deposit of red clay mixed with crushed stone and rock remnants. Since Sogdian ash is drought tolerant dry air well, due to its resistance to heat and soil salinity, it can be recommended in order to preserve biodiversity, for landscaping, and for improving ecosystem conditions.

Comparative Anatomical Study of Fronto-Orbito-Zygomatic and Fronto-Temporal Approach to the Central Skull Base

Despite the advances in microsurgery and neuroanatomy, surgery of the central skull base still represents a challenge. Fronto-temporal approach has represented the mainstay of surgical approaches to this region. With advances in skull base surgery, orbital and zygomatic extensions were added to fronto-temporal approach to improve exposure minimizing brain retraction.The authors compared fronto-temporal and fronto-orbitozygomatic approaches to the central skull base by using the previously described operability score, to three different anatomical targets: the ipsilateral anterior clinoid process, the contralateral anterior clinoid process, and the ipsilateral posterior clinoid process.Based on the measurements taken, fronto-orbitozygomatic approache showed higher values at all 3 targets. The reported values were critically discussed.The operability score has been reported as an effective method to compare surgical approaches. The present study demonstrated the maximal possibility of exposure of the two approaches. Based on the strong variability of this anatomical region, especially because of the different pathologies, the authors suggest considering the operability score as a further tool to better define the best surgical approach to this anatomical region.

Facial musculature in naked mole‐rats ( Heterocephalus glaber )

Naked mole-rats (Heterocephalus glaber) are fossorial rodents with an unusually long-life span and eusocial niche. They are from the Bathyergidae family and their unusual anatomical and physiological traits, including several adaptations to their fossorial and eusocial niche, have been relatively under-studied compared to other rodent species. Their adaptations to a subterranean niche and eusociality are demonstrated by their large incisors, oral folds, and highly developed tactile system (incisors and tactile hairs covering their body). Naked mole-rats utilize their large incisors for social interacting, defense, navigation, object manipulation, feeding, and digging. Their oral folds close caudal to their incisors to prevent dirt from entering their oral cavity while digging. Their well-developed tactile system compensates for their reduced visual (functionally blind) and auditory systems (reduced pinnae). Naked mole-rat facial musculature would also be expected to have evolved and express neotenic features as an adaption to a fossorial niche. There are few studies that have characterized facial musculature in naked mole-rats. Therefore, we performed detailed facial muscle dissections of adult naked mole-rats, which included the presence and attachment sites. We compared our dissections with comparative anatomical studies. Our dissections showed subterranean adaptations to face musculature in naked mole-rates, including reduced musculature associated with ear and eye movements. Further, our findings provide insight into the ecological and evolutionary adaptations of naked mole-rat facial musculature to a subterranean niche.

Studiul anatomic comparativ al frunzelor speciei Lycium barbarum L.

A study has been carried out on the anatomical structures of the species Lycium barbarum L. and of the goji varieties from the collection of the National Botanical Garden (I) “Alexandru Ciubotaru”, grown under the pedo-climatic conditions of the Republic of Moldova. The comparative anatomical study was performed on a complex of anatomical indices: cuticle type, bristles, stomata, calcium oxalate crystals.

A Comparative Study of Anatomical and Taxonomical of Juniperus Species Grown in Northern Iraq

This comparative anatomical taxonomic study was conducted for 3 species belonging to the genus Juniper of the Cupressaceae family that grow wild in northern Iraq, in 7 sites distributed over the governorates of Nineveh, Dohuk and Sulaymaniyah, and these species are (Juniperus oxycedrus L., Juniperus polycarpos K. Koch and a new species that was recorded for the first time in the Flora of Iraq by the same researchers, which is Juniperus macrocarpa Sibth and Sm.). The study included the chemical separation of wood Maceration, the results showed the variation of the studied species in the dimensions of the tracheids (like length, diameter of the tracheids and wall thickness) and in the Runkel ratio as well as the variation in the dimensions of the Borderd pits. It was possible to diagnose and isolate the two species of J. oxycedrus and J. Macrocarpa that have similar phenotypes, as the species J. macrocarpa had longer, wider and thicker tracheids than those of J. oxycedrus, while the species J. Polycarpos had the lowest average tracheids length, diameter and thickness; Thus, it was isolated from the previous two species. Regarding the Runkel ratio, the results showed that all types of juniper studied are suitable for the manufacture of pulp and paper. And that is because they have Runkel ratios that have fallen within the approved range for the best production and quality of the paper pulp, as the values for the studied species were limited to between (0.425 - 0.922). The lined click diameters were also varied according to species. It was also found that the qualitative characteristics of the tracheids have a prominent role in the diagnosis of the studied species, as they are constant genetic characteristics of the species, as it was found that there are variations in the qualitative characteristics between the studied species, such as the presence of Thickening Helical in the tracheids of J. oxycedrus, in addition to the presence of Dentate in the walls His tracheids and their absence in the other two species, as well as the presence of two rows of bordered pits in the tracheids of juniper, which is called the Biseriate, and their absence in the other two species. It was evident from these results that the anatomical characters of the wood have a great taxonomic importance that contributed to the diagnosis of Juniper species. This is the first time in the Iraqi country that an anatomical diagnostic key has been placed for the wood of Juniperus L. species growing in northern Iraq . The woods of this studied species.

A REVIEW ON ANATOMICAL METHODS IN PLANT SYSTEMATICS

The comparative study of plant structure, morphology, and anatomy has always been the backbone of plant systematics. Anatomical characteristics are important evidence when elucidating the relationships among higher plants. Therefore the anatomical information can be taxonomically useful without having obvious evolutionary or phylogenetic interpretation. This review is a comprehensive study of the plant anatomical methods used by various researchers using different plant sources like leaf, petiole, and stem

Morphological Investigations on Epistropheus in Ox and the Comparison of it with Resembling Bone in Horse, Dog, Sheep and Goat

Background: The documentation of anatomical features of epistropheus, which is also called as axis (C2) in different animals is not abundantly available on record. The observance of this C2 bone in ox made and compared it with the similar bone in different species of animals as to Horse, Dog, Sheep and Goat. The axis of ox was positioning cranially with spout like odontoid process which called as the dens. It was projected from the body. Due to its tooth like process, it was also known as vertebra dentata. The blade like supraspinous cranial process had increasing height and thickness towards its caudal progression, however, its infraspinous process was observed as the median ridge. While knowing such differential anatomical characters of axis (C2) in different species of animals as to Horse, Dog, Sheep and Goat this study is undertaken for comparison with the axis of Ox. Aims: Present endeavour aiming to have the comparative anatomical studies of the epistropheus i.e. axis (C2) bone of Ox and its comparison with the similar bone of Horse, Dog, Sheep and Goat. Materials and Methods: Six dried samples of second cervical of Ox (Bos indicus) were collected and explored its anatomical features. The comparative anatomical studies of the similar bone were performed in different species including horse (Equus ferus), dog (Canidae canis), sheep (Ovis aries) and goat (Capra hircus). Results: In horses, epistropheus i.e. axis the axis had longer body than the ox. The dens was conical and narrow. The axis of dog had cylindrical longer dens. Large and heightened spine as the pendant was observed, which was terminating caudally by the tuberosity of two crests. The axis of sheep had small, blunt and convex dorsal spinous process without remarkable ventral spine. The axis of goat had thin and heighted dorsal spinous process that overlaps the adjacent cranial and caudal cervical vertebrae. Conclusion: The findings of present studies are not only bringing the expositions of axis, the important bone of cervical region in different animals but also this is sufficiently bringing the fullest use for radiographic anatomy. KEY WORDS: Anatomy, Axis, Epistropheus, Ox, Horse, Dog, Sheep, Goat.

Endoscopic sublabial transmaxillary approach to the inferior orbit: pearls and pitfalls-A comparative anatomical study.

Although orbital surgery has always represented a challenge for neurosurgeons, keyhole and endoscopic techniques are gradually surging in popularity maximizing functional and esthetic outcomes. This quantitative anatomical study first compared the surgical operability achieved through three endoscopic approaches within the inferior orbit: the endoscopic sublabial transmaxillary (ESTMax), the endoscopic endonasal transethmoidal (EETEth), and the endoscope-assisted lateral orbitotomy (ELO). Each of these approaches was performed bilaterally on five specimens. We described the ESTMax step-by-step, underlining its advantages and pitfalls in comparison with EETEth and ELO. Then, we assessed surgical measurements and operability in ESTMax, EETEth, and ELO. The ESTMax provided the most favorable operative window (278.9 ± 43.8 mm2; EETEth: 240.8 ± 21.5 mm2, p < 0.001; ELO: 263.1 ± 19.8 mm2, p = 0.006), the broadest surgical field area (415.9 ± 26.4 mm2; EETEth: 386.7 ± 30.1 mm2, p = 0.041; ELO: 305.2 ± 26.3 mm2, p < 0.001), surgical field depths significantly shorter than EETEth (p < 0.001) but similar to ELO, the widest surgical angles of attack (45°-65°; EETEth: 20°-30°, p < 0.001; ELO: 25°-50°, p < 0.001), and the greatest surgical mobility areas (EETEth: p < 0.001; ELO: p < 0.001). Furthermore, the ESTMax allowed multi-angled exposure and handy maneuverability around all the inferior intraorbital targets. Small anterior antrostomy, blunt intraorbital dissections, direct targets' approach, orbital floor reconstruction, and maxillary bone flap replacement may limit the ESTMax morbidity rates. The ESTMax is a minimally invasive "head-on" orbital approach that exploits endoscopic surgery advantages avoiding the cranio-orbital and trans-nasal approach limitations and possible complications. It represents a promising alternative to EETEth and ELO because of its optimal operability for resecting lesions extending into the entire inferior orbit.

Comparative angiotomographic study of swine vascular anatomy: contributions to research and training models in vascular and endovascular surgery.

BackgroundMedium and large animal models allow researchers to evaluate the efficacy and safety of cardiovascular procedures in systems that resemble human anatomy and can be used to simulate scenarios for training purposes. Although porcine models have been used extensively, many physiological and anatomical features remain unknown or only superficially described.ObjectivesTo describe the normal porcine vascular anatomy on computed tomography scans, compare it to human vascular anatomy, and discuss the application of porcine models for open and endovascular procedures.MethodsThree male Landrace pigs underwent computed tomography. The vascular anatomy of the neck, thorax, abdomen, and limbs was analyzed and described; relevant similarities and differences between porcine and human vascular anatomies and the implications for vascular procedures in pigs are highlighted.ResultsThe carotid territory, aortic arch, and terminal aorta branches all show marked differences in pigs compared to their human counterparts. Compressions of both left renal and common iliac veins were detected, analogous to those seen in human Nutcracker and May-Thurner syndromes. Vascular measurements (diameters, lengths, and angles) of several different porcine territories are presented.ConclusionsThe data presented should be useful for planning preclinical trials and basic research and for refining surgical training using porcine models in vascular fields.

Comparative anatomy study of teeth types in Barracauda and Tilapia fish

This study investigates the general morphology and the ultrastructure of teeth types in adults of 2 fish species (the baracouda, Sphyraena barracuda, and the Nile Tilapia, Oreochromis niloticus). Also, it investigates the relationship between teeth types in fish and its feeding habits, where tilapia is an herbivore while barracuda is a carnivore. The present work has applied the anatomy of barracuda and tilapia and analyzed the types of teeth and how they work. The teeth were investigated by binocular microscope and scanning electron microscopy to determine the shape of teeth in both barracuda and tilapia and determine the method of using these teeth in feeding. The results indicated that there is a difference between barracuda and tilapia teeth in structural morphology and type. This difference was demonstrated by virtual and microscopic examination, and this is due to the different feeding habits of both barracuda and tilapia.

The transsylvian corridor through minimally invasive transcranial approaches: a comparative anatomical study.

Minimally invasive transcranial approaches (MITAs) continue to expand in popularity in neurosurgery. Only few MITAs allow sufficient sylvian exposure to enable wide use of the transsylvian corridor. In this study, we aim to compare the transsylvian corridor in two MITAs: the minipterional (MPTa) and the extended supraorbital eyebrow approaches (XSEa). Eight cadaver heads were used to quantify the surgical exposure and maneuverability along the sylvian fissure and the insular lobe provided by the MPTa and the XSEa. Surgical exposure was calculated by means of the exposed length of the sylvian fissure and by the area framed within three extreme points in the insular lobe. Maneuverability was assessed by means of the surgical freedom along the sylvian cistern. XSEa provides twice the frontal exposure and half of the temporal exposure in comparison to the MPTa (p < 0.001 and p = 0.02, respectively). No significant differences were found between the two craniotomies in the length of the exposure of the sylvian fissure, area of insular exposure, or surgical freedom. Both the MPTa and the XSEa afford sufficient grades of exposure along the sylvian fissure and the insular lobe, although the viewing angle is significantly different between the two approaches. Such properties allow either to be used for microsurgery deep within the sylvian cistern. The use of additional corridors, such as the subfrontal route (XSEa) and pretemporal route (MPTa), may influence selection of either the minipterional or the extended supraorbital approaches according to the origin of the surgical pathology addressed.

Comparative Anatomical Features Study of the Some Medicinal Rumex Species Distributed in Turkey

Distributed in Turkey Rumex crispus L., Rumex patientia L., anatomical features of Rumex obtusifolius species were comparatively investigated in this study. For anatomical studies, cross-sections were taken from root, stem and leaf. In addition, superficial sections were taken from the leaf and stomata index and stomata features were determined. Similarities and differences of taxa are revealed. There were druse crystals at the root of the R. obtusifolius plant. The radial-shaped vascular bundles in the root of R. crispus had 4-5 arms. Glandular hair was found only in the body of R. obtusifolius. It is also characteristic that vascular bundles were scattered in the stem of this species. There was cuticle in the stem of R. crispus. Stem corner numbers of taxa can also be seen as a distinguishing feature in terms of species. R. crispus was 10, R. obtusifolius was 8, R. patientia was 14 cornered. The number and type of collenchyma layer in the stem of the species were also different Outward bulge was detected in the middle-vascular region of leaves of the taxa. This bulge was less pronounced in R. crispus and the most prominent in R. obtusifolius. At least the number of stomata was observed on the R. obtusfolius leaf. Leaf epidermis cell walls were wavy in R. patientia.

Histological changes in the structure of one-year sprouts of Pinus sylvestris L. as a reflection of the structural adaptation of the species during its introduction

Comparative anatomical studies of one-year sprouts Pinus sylvestris L. made it possible to obtain data on the features of vegetative organ formation, histological changes and the persistence of structural features by the influence of environmental factors. It is noted that the parameters of histological structure and cytological indexes of one-year sprouts are strongly influenced by the hydrothermal coefficient (HTC) of growing conditions. The structure of the one-year sprouts of Pinus sylvestris L., growing in sufficient humidification (HTC=1.6) conditions, is characterized by the greatest thickness of cortex, phloem and xylem, the largest radius of pith, the maximum diameter of resin canals, while having the smallest size of external protective tissues. Histological studies of the geographical cultures of Pinus sylvestris L. of the central forest-steppe revealed, that being in the same growth conditions, the anatomical structure of one-year sprouts significantly changes. Histological and cytological indexes of the anatomical structure of the one-year sprouts of Pinus sylvestris L. populations from the dry steppe increase by 33%, from the broad-leaved forest zone decrease to 30%. Thus, structural adaptation of the assimilation apparatus to new growing conditions occurs, which determines in general the productivity and stability of the woodlands of Pinus sylvestris L.

Mini-Invasive Endoscopic Approaches to the Maxillary Sinus Floor: A Comparative Anatomical Study

While middle antrostomy (MA) is the most common approach to the maxillary sinus (MS), it is known for not allowing to fully inspect the whole MS, especially in its inferior and anterior portions. To overcome this limitation, alternative approaches have been proposed, such as inferior antrotomy (IA) and canine fossa accesses (CFA). Given the lack of studies on the MS floor visualization with different accesses, our study aims, in a cadaver lab setting, to systematically compare three different approaches (MA, IA and CFA) in these regards. Eight cadaver heads, previously submitted to CTscan, were prepared inserting fixtures corresponding to teeth 2, 4, 6, 11, 13 and 15 and into the canine fossae. Three approaches were prepared: a wide MA, an IM and a CFA. We endoscopically evaluated, for each specimen, side, access type and scope angle (0°, 30°, 45°, and 70°), which fixtures were visible on the maxillary sinus floor and whether the canine fossa fixture was visible (MA and IA only). IA allowed to visualize all fixtures in nearly all cases (14/16 with 70° endoscope), while MA showed poor visualization results (3/16 with 70° endoscope); CFA failed to gain full visualization in most specimens (7/16 with 70°endoscope). Such difference was statistically significant. MA proved unable to visualize the canine fossa fixture in most cases while IA showed excellent possibilities. All differences were statistically significant (p < .001, Mcnemar's test). Our data show that the IA grants a statistically significant superior surgical field vision when compared to MA and CFA, though in vivo validation of these results is still required.

Evolutionary and ontogenetic changes of the anatomical organization and modularity in the skull of archosaurs

Comparative anatomy studies of the skull of archosaurs provide insights on the mechanisms of evolution for the morphologically and functionally diverse species of crocodiles and birds. One of the key attributes of skull evolution is the anatomical changes associated with the physical arrangement of cranial bones. Here, we compare the changes in anatomical organization and modularity of the skull of extinct and extant archosaurs using an Anatomical Network Analysis approach. We show that the number of bones, their topological arrangement, and modular organization can discriminate birds from non-avian dinosaurs, and crurotarsans. We could also discriminate extant taxa from extinct species when adult birds were included. By comparing within the same framework, juveniles and adults for crown birds and alligator (Alligator mississippiensis), we find that adult and juvenile alligator skulls are topologically similar, whereas juvenile bird skulls have a morphological complexity and anisomerism more similar to those of non-avian dinosaurs and crurotarsans than of their own adult forms. Clade-specific ontogenetic differences in skull organization, such as extensive postnatal fusion of cranial bones in crown birds, can explain this pattern. The fact that juvenile and adult skulls in birds do share a similar anatomical integration suggests the presence of a specific constraint to their ontogenetic growth.