Paranasal Sinus System Research Articles

Radiographic anatomy of the nasal conchal bullae and conchal sinuses in mature horses.

The dorsal and ventral nasal conchal bullae and conchal sinuses are part of the complex equine paranasal sinus system and are commonly affected by secondary sinusitis. However, the radiographic anatomy of the conchal sinuses is poorly reported in the literature. The present study aimed to describe the radiographic anatomical characteristics of the nasal conchal bullae and conchal sinuses in mature horses. Six equine cadaveric heads without sinus or dental disorders were studied. A maxillary sinusotomy was performed to identify the dorsal and ventral nasal conchal bullae and conchal sinuses, allowing the application of radiopaque contrast medium in these structures. Afterward, the same projections were repeated. Laterolateral views allowed an adequate visualization of nasal conchal bullae and conchal sinuses; however, they overlapped the same contralateral structure. In the latero30°dorsal- lateroventral obliqueview, the same structures were easily recognizable, but in an oblique view, the structures were projected dorsally in relation to the contralateral one. The dorsoventral view allowed partial visualization of the dorsal conchal bullae and dorsal sinuses, but it was not possible to identify the ventral conchal sinus and ventral conchal bullae. The offset dorsoventral view helped in the identification of the dorsal conchal bullae and dorsal conchal sinus, also achieving visualization of the medial region of the ventral conchal sinus and ventral conchal bullae. The use of contrast medium, added to the anatomical dissection, allowed a better radiographic identification of the sinuses and conchal bullae. The combination of different radiographic views is recommended for the evaluation of these structures.

Anatomy and computed tomography of the nasal cavity, nasal conchae, and paranasal sinuses of the endangered Patagonian huemul deer (Hippocamelus bisulcus).

This study explores for the first time the shape, volume, and configuration of nasal cavity structures of the endangered Patagonian huemul deer via computed tomography (CT). Three-dimensional (3D) reconstructions derived from data sets obtained from five Patagonian huemul deer skulls were analyzed. Using semiautomatic segmentation, 3D models were created of all the sinus compartments and nasal conchae. Volumetric measurements were taken of seven sinus compartments. The Patagonian huemul deer has a wide, large nasal cavity, with an osseous nasal aperture typical of cervids and a choana with characteristics that differentiate it from the pudu and roe deer. It also has six nasal meatuses and three nasal conchae, with the ventral nasal concha having the greatest volume and surface, which given its extension ensures a greater ability to humidify and heat the air. Further analysis showed the complex system of paranasal sinuses to be characterized by a rostroventral and interconnected group, where communication with the nasal cavity is common through the nasomaxillary opening, and a caudodorsal group that communicates with the nasal cavity through openings in the nasal meatuses. Our study of the endangered Patagonian huemul deer documents an intricate, and in some nasal cavity structures, unique morphological construction which may predispose it to higher rates of sinonasal afflictions due largely to its nasal complex anatomy, thus affecting its high cultural value.

A Case of Nasal NK T-Cell Lymphoma Presenting With Persistent Epiphora

Nasal type natural killer/T-cell lymphoma (NNKTL) is a rare and aggressive subtype of non-Hodgkin lymphoma originating from a natural killer cell or γδ T cell infected by the Epstein-Barr virus. It usually invades the aerodigestive tract and can rapidly destroy the paranasal sinus, hard palate, and central nervous system. NNKTL is often mistaken for benign conditions such as chronic hypertrophic rhinosinusitis or mucosal inflammatory change, as endoscopic findings of NNKTL presenting nasal mucosal hypertrophy are similar to endoscopic findings for these abovementioned benign conditions. Here, the authors report the diagnosis and examination of NNKTL in a 58-year-old male patient who visited our clinic for nasal cavity discomfort after he underwent a dacryocystorhinostomy to treat dacryocystitis.

Correlation between computed tomography, magnetic resonance imaging and cross-sectional anatomy of the head of the guinea pig (Cavia porcellus, Linnaeus 1758).

The current work aimed to study the anatomical features of the guinea pig's head by two medical imaging techniques: computed tomography (CT) and magnetic resonance imaging (MRI), and their correlation with the anatomical cross-sectional images. Six adult healthy guinea pigs were used in the present study. Two heads were imaged by CT scanner and then by MRI. The examined heads were cut sagittally and transversely, and two skulls were macerated. The anatomical features were identified on the anatomical sections and compared with the tomographic and MRI images obtained. Data were presented as three-dimensional reconstructed images of the head. In addition, representative combinations of the sagittal and transverse anatomical sections and the corresponding CT scans and MRI images were also presented. Reconstruction of CT images enabled the visualization of different bony structures and airways of the guinea pig head. In addition, skull bones were easily visualized on CT scans, while different parts of the brain were identified on MRI images. Air cavities could be identified by their different contrast on the CT scans and their low intensity on MRI images. The study showed that guinea pig had poorly developed paranasal sinus system represented by rostral and caudal maxillary sinuses. On the contrary, the guinea pig had two tympanic bullae: a small dorsal and a large ventral bulla. In conclusion, this study provides one of the first investigations that uses the multislice CT scans and MRI to study the guinea pig's head and their correlation with the corresponding anatomical sections.

Paranasal sinus system and upper respiratory tract evolution in Mesozoic pelagic crocodylomorphs.

Thalattosuchians were a predominately marine clade of Mesozoic crocodylomorphs, including semi-aquatic teleosauroid and obligately pelagic metriorhynchid subclades. Recent advances in our understanding of thalattosuchian endocranial anatomy have revealed new details of the evolutionary transition from terrestrial to marine to pelagic taxa. Paranasal sinuses, however, have received little attention. Herein, we investigate the evolution of the paranasal sinus system and part of the upper respiratory system (nasopharyngeal ducts) in Thalattosuchia, by reconstructing the nasal and paranasal anatomy in CT scans of seven thalattosuchian skulls: one teleosauroid, two basal metriorhynchoids and four metriorhynchids. Our outgroups were: three extant crocodylian species (including adult and subadult skulls) and the basal crocodyliform Protosuchus. We found thalattosuchians exhibit exceptionally reduced paranasal sinus systems, solely comprising the antorbital sinus, as has been previously proposed. The semi-aquatic basal thalattosuchians Palgiopthalmosuchus gracilirostris and Pelagosaurus typus both have an antorbital sinus partially located medial to a reduced external antorbital fenestra and broadly communicating with the dorsal alveolar canal. In pelagic metriorhynchids, the antorbital cavity is more extensive than in basal taxa and possibly had an active function associated with a hypothesized accessory suborbital diverticulum, but our reconstructions are insufficient to confirm or reject the presence of such a diverticulum. The nasopharyngeal ducts of metriorhynchids are dorsoventrally enlarged, possibly enabling stronger ventilation. The sequence of acquisition of craniofacial adaptations show a mosaic pattern and appears to predate many skeletal adaptations, suggesting these changes occurred early in the thalattosuchian marine transition.

Active airflow of the paranasal sinuses in extinct crocodyliforms: Evidence from a natural cast of the thalattosuchian Dakosaurus andiniensis.

The evolution of Thalattosuchia documents the unique shift among Crocodylomorpha from aquatic continental/coastal habitats to a fully pelagic lifestyle. This transition was coupled with deep modification of their skeletons, such as hydrofoil forelimbs, hypocercal tail, and loss of osteoderms. The natural snout casts of the rhacheosaurin Cricosaurus araucanensis showed that it also included changes in the internal anatomy of the snout like the enlargement of nasal glands (probably for salt excretion) and the rearrangement of the paranasal sinus system, including the internalization of the antorbital sinus. Here we described the snout natural cast of the geosaurin Dakosaurus andiniensis from the Late Jurassic of Patagonia. The information provided by it indicates that, despite having different external morphologies and ecology, D. andiniensis and C. araucanensis share the same facial anatomy. The new cast preserves a suborbital diverticulum of the antorbital sinus protruding into the orbit through the postnasal fenestra. Its location indicates that it was interleaved with jaw adductor muscles suggesting an active airflow in the paranasal sinus. We provide a putative functional interpretation of this peculiar arrangement where bellow pumps actions of musculature may help drain salt glands. The rearrangement of the paranasal sinuses predates the transition to a completely pelagic-lifestyle. We proposed a stepwise evolutionary scenario of Thalattosuchia, implying changes in the preorbital region (and orbit orientation) where the internalized antorbital sinus via its subsidiary diverticulum was co-opted for helping nasal glands drainage. Further scrutiny of facial anatomy of a larger sample of thalattosuchians will help to test this hypothesis.

Volumetric measurements of paranasal sinuses and examination of sinonasal communication in healthy Shetland ponies: anatomical and morphometric characteristics using computed tomography

BackgroundDespite clinical importance and frequent occurrence of sinus disease, little is known about the size of paranasal sinuses and their communication in ponies and small horses. To examine the shape and volume of the paranasal sinuses and evaluate the sinonasal communication, three-dimensional (3D) reconstructions of computed tomography (CT) datasets of 12 healthy adult Shetland ponies were performed and analysed. Linear measurements of head length and width were taken. Using semi-automatic segmentation, 3D-models of all sinus compartments were created. Volumetric measurement of the seven sinus compartments were conducted and statistical analysis was performed. Sinus volumes were compared between the left and right sinuses and the relation to age and head size was evaluated.ResultsStructure and shape of the paranasal sinus system in Shetland ponies was similar to that of large horses. All seven sinus compartments on each side of the head were identified (rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, middle conchal sinus, frontal sinus, sphenopalatine sinus). The existence of a bilateral cranial and a caudal system formed by a maxillary septum was visible in all 12 individuals. The volumetric sizes of the left and right sinuses did not differ significantly (p > 0.05). A positive correlation between the size of the paranasal sinuses and the head length was shown. A relation between sinus volumes and age could not be proved in adult ponies aged > six years. Communication between single sinus compartments was identified. Furthermore, communication with the nasal cavity over the nasomaxillary aperture (Apertura nasomaxillaris) and a common sinonasal channel (Canalis sinunasalis communis) as well as its splitting up into a rostral and a caudolateral channel could be seen. Examination of the sinonasal communication was challenging and only a descriptive evaluation was possible.ConclusionsOur findings concerning the size, shape and volumetric dimensions of Shetland pony CT images could help improve CT interpretation of abnormal clinical cases as well as aiding clinicians to develop and select appropriate instruments for medical inspection and treatments.

Computed tomography and cross-sectional anatomy of the head in the red fox (Vulpes vulpes).

The red fox (Vulpes vulpes) is a universally widespread wild carnivore in the world. It has an important impact on human interests and plays a vital role in conservation biology. There is no report to describe computed tomography (CT) of the red fox head and its correlation with gross anatomy. Therefore, the intent of the present study was to document, by CT, the basic anatomical structures in the head region of the red fox to lay the groundwork of an appropriate anatomical description of the head structures comparable with traditional dissection technique. Three red fox heads were imaged sagittally and transversely using CT scanner. Six red fox heads were then serially cut, sagittally and transversely, by an electric band saw, and the obtained slices were cleaned and photographed. Different anatomical structures on CT images and the corresponding anatomic sections were identified and labelled. CT images revealed an excellent three-dimensional definition of bony structures of the entire craniofacial region. Moreover, CT scans revealed different contrasts between bones, oral and nasal cavities, paranasal sinuses and pharynx which enabled good visualization of those structures. The paranasal sinus system in red fox was poorly developed and represented by a frontal sinus and a small sphenoid sinus, in addition to a maxillary recess. In conclusion, the series of CT images of the normal red fox head presented in the current study will serve as an anatomical reference for the normal head of the red fox, which in turn will improve knowledge for clinical interpretation.

ЛІКУВАННЯ ПАЦІЄНТІВ З КІСТОЮ ВЕРХНЬОЩЕЛЕПНОЇ ПАЗУХИ ОДОНТОГЕННОГО ГЕНЕЗУ

Кісти верхньощелепної пазухи є достатньо поширеною патологією системиприносових пазух, яка має мультифакторну етіологію, що продовжує активнодосліджуватися. Протягом останніх років особлива увага дослідників сконцентрована на роліхронічного запалення коренів зубів, які безпосередньо прилягають до нижньої стінкимакзилярного синусу, і відповідно втягують в патологічний процес навколишні структури.Одним із об’єктивних показників вираженості запалення є рівень матрикснихметалопротеїназ, зокрема матриксної металопротеїнази 9 (ММП9). Таким чином, метоюроботи є вивчення ефективністі лікування пацієнтів з кістою верхньощелепної пазухиодонтогенного генезу у віддаленому періоді. Матеріали і методи. У дослідження ввійшло 150пацієнтів. Група 1 – 125 осіб (вік 20-69 років, чоловіки - 58, жінки – 67), група 2 - 25 пацієнтів(вік 21-59 років, 11 чоловіків і 14 жінок). Всім пацієнтам з обстежуваних груп було проведенохірургічне лікування - видалення кісти верхньощелепної пазухи через нижній носовий хід, зподальшим консервативним лікуванням; пацієнтам першої групи в післяопераційному періодібуло проведено ревізію каналів зубів верхньої щелепи з заміною пломбувального матеріалу, апацієнтам другої групи дане втручання не проводилося. Критерій включення – підвищення рівняММП9 у слині. Критеріями виключення стали наявність гострого захворювання за 3 місяці дооперації, лікування у стоматолога за 3 місяці до хірургічного втручання, нормальний рівеньММП9 у слині. У процесі передопераційної підготовки, всім пацієнтам було проведено КТнавколоносових пазух, ендоскопічне дослідження порожнини носа і носоглотки,ринопневмометрію, визначення показника мукоциліарного кліренсу, активності ММП-9 в слині.Дослідження активності ММП-9 в слині проводилося з використанням ELISA kit.Статистична обробка даних виконувалася з використанням ПЗ IBM SPSS Statistics 22.Результати. Рівень ММП9 у слині пацієнтів першої групи склав 1347 (± 328) нг / мл, другої -1410 (± 220) нг / мл. Кількість рецидивів кісти в/щ пазухи у групі 1 була 8 випадків, що склало6,4% від загальної кількості. Серед інших ускладнень: міцетома в/щ пазухи - 4 ороантральнанориця - 1, хоанальний поліп - 2. . Кількість рецидивів кісти в/щ пазухи у групі 2 була 9 випадків(36%), міцетома в/щ - 3 випадки, ороантральна нориця - 1, хоанальний поліп - 1. Висновок.Отримані результати свідчать про вищу імовірність розвитку рецидиву кістиверхньощелепної пазухи за відсутності наступної ревізії коренів зубів і навколокореневихділянок, що безпосередньо межують із нижньої стінкою пазухи.

MgNd2 alloy in contact with nasal mucosa: an in vivo and in vitro approach.

Biodegradable and biocompatible magnesium alloys appear to be very promising not only for temporary clinical application but also for developing deformable and degradable medical implants. This study analyzes the in vivo degradation behavior and the impact on the paranasal sinuses of the highly ductile Mg-2wt%Nd alloy (MgNd2) in order to provide a basis for a satisfying stent system for the therapy of a chronic sinusitis. Moreover, in vitro tests were carried out on primary porcine nasal epithelial cells (PNEC). For the in vivo tests, cylindrical MgNd2 specimens were implanted into the sinus' mucosa of minipigs. During and after a total period of 180days the long-term biodegradation and biocompatibility properties after direct contact with the physiological tissue were analyzed. Biodegradation was investigated by measuring the mass and volume losses of the MgNd2 specimens as well as by performing element analyses to obtain information about the degradation layer. The influence on the surrounding tissue of paranasal sinuses was evaluated by endoscopic and histopathological examinations of the mucosa. Here, only a locally unspecific chronic infection was found. The degradation rate showed a maximum after 45days postsurgery and was determined to decrease subsequently. In vitro experiments using PNEC showed adequate biocompatibility of MgNd2. This study demonstrates a good in vivo biocompatibility for MgNd2 in the system of paranasal sinuses and underlines the promising properties of alloy MgNd2 for biodegradable nasal stent applications.

Current Concepts in the Treatment of Fractures and Tumor-Related Infiltration of the Anterior Skull Base

A total of 196 patients were treated surgically because of complex midfacial, and skull base fractures in the ENT Clinic of University of Lübeck between 2008 and 2012. Diagnosis was performed by computerized tomography. It will be a demonstrated case where the entire skull base was replaced with a titanium mesh. Another aspect represents the tumor-related infiltration of the anterior skull base. Overall 67 patients were treated in the past 7 years due to a malignant tumor of the nose and paranasal sinus system. In addition to rare entities (aesthesioneuroblastome, malignant melanoma, and metastasis of a clear cell Nieren carcinoma) were primarily squamous cell and adenocarcinoma before. Therapeutic surgical resection was performed with the following radiotherapy, brachytherapy, or simultaneous radiochemotherapy in the first place. For very advanced findings such as with intracranial spread, we performed the resection interdisciplinary in collaboration with neurosurgery. The different approaches will be demonstrated.

The sinonasal communication in the horse: examinations using computerized three-dimensional reformatted renderings of computed-tomography datasets

BackgroundSinusitis is a common disease in the horse. In human medicine it is described, that obstruction of the sinonasal communication plays a major role in the development of sinusitis. To get spatial sense of the equine specific communication ways between the nasal cavity and the paranasal sinuses, heads of 19 horses, aged 2 to 26 years, were analyzed using three-dimensional (3D) reformatted renderings of CT-datasets. Three-dimensional models were generated following manual and semi-automated segmentation. Before segmentation, the two-dimensional (2D) CT-images were verified against corresponding frozen sections of cadaveric heads.ResultsThree-dimensional analysis of the paranasal sinuses showed the bilateral existence of seven sinus compartments: rostral maxillary sinus, ventral conchal sinus, caudal maxillary sinus, dorsal conchal sinus, frontal sinus, sphenopalatine sinus and middle conchal sinus. The maxillary septum divides these seven compartments into two sinus systems: a rostral paranasal sinus system composed of the rostral maxillary sinus and the ventral conchal sinus and a caudal paranasal sinus system which comprises all other sinuses. The generated 3D models revealed a typically configuration of the sinonasal communication ways. The sinonasal communication started within the middle nasal meatus at the nasomaxillary aperture (Apertura nasomaxillaris), which opens in a common sinonasal channel (Canalis sinunasalis communis). This common sinonasal channel ramifies into a rostral sinonasal channel (Canalis sinunasalis rostralis) and a caudo-lateral sinonasal channel (Canalis sinunasalis caudalis). The rostral sinonasal channel ventilated the rostral paranasal sinus system, the caudo-lateral sinonasal channel opened into the caudal paranasal sinus system. The rostral sinonasal channel was connected to the rostral paranasal sinuses in various ways. Whereas, the caudal channel showed less anatomical variations and was in all cases connected to the caudal maxillary sinus. Volumetric measurements of the sinonasal channels showed no statistically significant differences (P <0.05) between the right and left side of the head.ConclusionsUnder physiologic conditions both paranasal sinus systems are connected to the nasal cavity by equine specific sinonasal channels. To resolve sinus disease it is aimed to maintain or even reconstruct the normal anatomy of the sinonasal communication by surgical intervention. Therefore, the presented 3D analyses may provide a useful basis.

The snout of Cricosaurus araucanensis : a case study in novel anatomy of the nasal region of metriorhynchids

Metriorhynchids are the only crocodyliforms adapted to pelagic marine life. Snout natural endocasts of the Tithonian (Late Jurassic) metriorhynchid Cricosaurus araucanensis indicated that skeletal changes defining the peculiar metriorhynchid body plan were coupled with changes of the soft cephalic anatomy such as the enlarged salt glands and restructuring of the paranasal sinus system. Seven new natural endocasts of the snout and a 3-D reconstruction of C. araucanensis are described. Data from these casts and the reconstruction are congruent, and they are combined into an accurate reconstruction that improves our knowledge of the pre-orbital anatomy. The olfactory tract, bulbs, olfactory nasal region and the anterior extension of the antorbital sinus within the maxilla are recognized. Osteological correlates of the salt gland body are also proposed. Palaeobiological inferences are erected based on the integration of natural endocasts and 3-D reconstruction data. It is proposed that C. araucanensis nasal salt glands were highly vascularized with a blood supply comparable with those of extant marine birds. Reduced olfactory bulbs and olfactory nasal region indicate that the aerial olfaction, differing from extant crocodilians, was not well developed.

Evaluation of an image-guided navigation system in the training of functional endoscopic sinus surgeons. A prospective, randomised clinical study

Introduction: Many sinus surgeons report improved spatial orientation after using a navigation system. This study investigates the surgical, ergonomic and economic aspects of using a navigation system in training and teaching. Materials and methods: Eight rhino-surgeons in training and 32 patients with bilateral diseases of the paranasal sinus system were included. After randomisation, one patient`s side was operated on with a navigation system while the other side was operated on without navigation. It was monitored how often the surgeon used the navigation pointer and then changed the procedures. A standardised and validated interview recorded the cognitive load when using the navigation system and the application efficiency. Results: The operations lasted on average 16 minutes longer with the navigation. Five paranasal sinuses could not be found in the control group without navigation. In only 10-13% of cases did the surgical procedure change after the use of the pointer. Most of the surgeons admitted that particular steps of the operation were more reliable and safer to carry out with the navigation system. The general trust in the system rose in proportion to intraoperative accuracy and repeated use. Conclusion: Overall, there was an overwhelming level of trust in the navigation system. Trainee sinus surgeons seeing their more experienced colleagues using a navigation device tend to overestimate the possibilities of the system and to underestimate the risks. The assistance system was used particularly effectively in the group of slightly more experienced surgeons. In this group, the additional expenditure of time was less and the navigation substantially contributed to reinforcing the anatomical sense of direction.

Evaluation of an image-guided navigation system in the training of functional endoscopic sinus surgeons. A prospective, randomised clinical study

Many sinus surgeons report improved spatial orientation after using a navigation system. This study investigates the surgical, ergonomic and economic aspects of using a navigation system in training and teaching. Eight rhino-surgeons in training and 32 patients with bilateral diseases of the paranasal sinus system were included. After randomisation, one patient`s side was operated on with a navigation system while the other side was operated on without navigation. It was monitored how often the surgeon used the navigation pointer and then changed the procedures. A standardised and validated interview recorded the cognitive load when using the navigation system and the application efficiency. The operations lasted on average 16 minutes longer with the navigation. Five paranasal sinuses could not be found in the control group without navigation. In only 10-13% of cases did the surgical procedure change after the use of the pointer. Most of the surgeons admitted that particular steps of the operation were more reliable and safer to carry out with the navigation system. The general trust in the system rose in proportion to intraoperative accuracy and repeated use. Overall, there was an overwhelming level of trust in the navigation system. Trainee sinus surgeons seeing their more experienced colleagues using a navigation device tend to overestimate the possibilities of the system and to underestimate the risks. The assistance system was used particularly effectively in the group of slightly more experienced surgeons. In this group, the additional expenditure of time was less and the navigation substantially contributed to reinforcing the anatomical sense of direction.

The Drainage System of the Paranasal Sinuses: A Review with Possible Implications for Balloon Catheter Dilation

Intersinus connections and accessory ostia of the maxillary sinus are well known to rhinologic surgeons but are less known for the remaining paranasal sinuses. Probing and dilatation of the natural ostia of diseased sinuses is being popularized currently by the clinical value of balloon catheter dilation (BCD). Although short-term high success rates with treatment of the dilated ostia/duct have been reported with this technique, the potential impact of fractures of adjacent bony septae on accessory sinus ostia, on mucosally lined surfaces, and on intersinus drainage pathways still has not been considered. The aim of this study was to review the literature on accessory sinus ostia, intersinus connections, and mucociliary drainage pathways for the entire sinus system that are relevant to BCD. A literature review was performed. Accessory sinus ostia exist for each paranasal sinus. Many sinuses drain not only directly into the nasal cavity but also indirectly through adjacent sinuses. Of note, one major drainage pathway of the frontal sinus is over the ethmoid sinuses and via the ethmoids into the maxillary sinus and subsequently into the nose. Drainage of the sphenoid sinus exists both through posterior ethmoidal cells and directly into the nasopharynx. Accessory ostia are not only common for the maxillary sinus but also for the entire paranasal sinus system. BCD may potentially inadvertently impair mucociliary clearance of the sinuses through effects on secondary drainage pathways.

Use of reversed periosteal flaps in the repair of large nasocutaneous fistulas in two horses

Summary Head injuries occur frequently in horses and a successful outcome after repair depends upon the severity of the initial trauma, the anatomical structures involved and the extent of tissue loss. Often these injuries involve facial bones and enter into the nasal passages or paranasal sinus system. When these injuries occur in conjunction with substantial tissue loss, the resulting defect may be difficult to close and naso/sinocutaneous fistulae can develop. These defects can be challenging and time consuming to repair and an appropriate reconstructive technique must be selected. We describe the use of reverse periosteal flaps as a technique in repairing large nasocutaneous fistulae in 2 horses after previous attempts to close the defects by other means had failed.

Details of the cranial anatomy of a primitive diplacodont brontothere, cf. Protitanotherium, from the Wiggins Formation of Wyoming (Mammalia, Perissodactyla, Brontotheriidae)

ABSTRACT A remarkably well-preserved primitive horned brontothere skull from the Wiggins Formation of western Wyoming is described. Noteworthy characters of this specimen include an extensive system of large paranasal sinuses, a distinct vomerine plate, and a confluence of the anterior lacerate foramen and foramen rotundum. A nearly complete endocranial cast allows for a description of the brain and many of the cranial nerves. Perhaps the most important structures described are the large openings on the basicranium, here dubbed “sphenoidal apertures,” which may be unique among the Brontotheriidae. Among North American brontothere taxa, the skull is closest in morphology to the holotype of Protitanotherium emarginatum Hatcher, but has some important differences that make assignment to that genus and species uncertain. If reference to the genus Protitanotherium is correct, then the name P. australis (Wilson) may apply, although this may be a junior synonym of P. superbum Osborn. Given the uncertainties, the specimen is identified only as cf. Protitanotherium for the purposes of the present paper. Regardless of which name should be applied, characters displayed by the specimen suggest that it is the primitive sister genus to all other diplacodont brontotheres.

Paranasal sinus system of Geosaurus araucanensis and the homology of the antorbital fenestra of metriorhynchids (Thalattosuchia: Crocodylomorpha)

ABSTRACT Metriorhynchids have been interpreted as the only archosaurs entirely adapted to pelagic marine life, given the deep morphological modifications of their skeletons. The most conspicuous feature in the skull involves the “fenestra and fossa antorbitalis complex.” Exceptionally preserved natural cast of snout cavities of Geosaurus araucanensis, found in the Late Jurassic of the Neuquén Basin (northwestern Patagonia, Argentina), allow exploration of the rostral anatomy of this metriorhynchid. The presence of a paranasal sinus system, hypothetically reconstructed by other authors using EPB method approach, can now be confirmed based on direct morphological evidence. We propose that the openings classically identified in the literature as internal and external antorbital fenestrae of metriorhynchid have been misidentified; the preorbital opening of metriorhynchids is a neomorph associated with a novel salt gland that evolved independent of the antorbital fenestra, and that the true antorbital cavity of G. araucanensis, as well as this cavity in all other metriorhynchids, is internalized. Although this hypothesis could be considered as unorthodox, it is the one that requires the least ad-hoc assumptions to explain observations. Many phylogenetic studies depict the Thalattosuchia nested within Neosuchia. In these trees, the successive outgroups of Thalattosuchia are Dyrosaurids/Pholidosaurids, followed by derived Neosuchians (Goniopholids, Bernissartia, Eusuchians). All these taxa have a closed antorbital fenestra. Within this phylogenetic scenario, the internalization of the antorbital cavity did not occur in the ancestor of thalattosuchians, but in the ancestor of a much more inclusive clade of neosuchians.

A description of the relationship between the nasomaxillary aperture and the paranasal sinus system of horses

Disease of the paranasal sinuses of the horse is common and treatment often involves lavage and sometimes surgery. The development of minimally-invasive, sinus-specific treatments, such as balloon sinuplasty, requires a thorough understanding of this complex anatomical region. To improve this understanding, 10 heads from dead horses of various ages were grossly dissected. The heads were transected sagittally and each half was dissected to expose the left and right nasomaxillary apertures and associated structures which were then photographed and measured. Entrances from the rostral and caudal maxillary sinuses into the maxillary aperture were found that led to a common exit at the middle nasal meatus. The caudal and rostral maxillary sinuses had their own, completely distinct outlets (entrances into the nasomaxillary aperture). There was no significant effect of side on measured variables.