Growth and microanatomy of the paranasal sinuses in two species of New World monkeys.

Paranasal sinuses of living apes and humans grow with positive allometry, suggesting a novel mechanism for bone enlargement. Here, we examine the paranasal sinuses of the owl monkey (Aotus spp.) and a tamarin (Saguinus midas) across postnatal development. The prediction that paranasal sinuses grow disproportionately faster than the main nasal chamber is tested. We used diffusible iodine-based contrast-enhanced computed tomography and histology to study sinuses in eight Aotus and three tamarins ranging from newborn to adult ages. Sinuses were segmented at the mucosa-air cavity interface and measured in volume. All sinuses were lined by a ciliated respiratory epithelium, except for the ethmoid air cells in Aotus, which are lined in part by olfactory epithelium. An age comparison indicates that only the maxillary sinus and ethmoid air cells are present in newborns, and two additional sinuses (invading the orbitosphenoid and the frontal bone), do not appear until late infancy or later. Comparing newborns and adults, the main nasal airway is 10 times larger in the adult Aotus and ~ 6.5 times larger in adult Saguinus. In contrast, the maxillary sinus far exceeds this magnitude of difference: 24 times larger in the adult Aotus and 46 times larger in adult Saguinus. The frontal sinuses add significantly to total paranasal space volume in both species, but this growth is likely delayed until juvenile age. Results suggest ethmoid air cells expand the least. These results support our prediction that most paranasal sinuses have a distinctly higher growth rate compared to the main nasal chamber.

History of nasopharyngeal study: A 5,000-year odyssey into our evolving understanding of a small but vital region.

The nasopharynx has been understudied relative to neighboring anatomical regions. It is a highly complex, integrated space whose function, development, and evolution remains unclear after nearly 5,000 years of study. Historically, most work on the nasopharynx was done with a focus on adjacent structures. It has most often been mentioned in relation to the middle ear (via the Eustachian tube) in ancient texts and has only later been given a designation as one of three portions of a tripartite pharynx among adult humans. As human dissection became practiced more widely in Renaissance Europe, understanding of the nasopharyngeal boundaries improved. With further advancements in the study of nasopharyngeal development, evolution, and anatomical variation from the 19th century up until the present, this region has been shown to be functionally vital and still complicated to define.

The nasopharynx as a window to half a billion years of evolutionary change to the upper respiratory tract.

The nasopharynx is a region at the nexus of several vital physiological systems, including the nasal cavity, oral cavity, braincase, middle ear, and cervical vertebrae. It has undergone pronounced morphological change over the course of tetrapod, mammalian, and human evolution. However, despite its place in evolutionary history, the nasopharynx has received relatively little attention. This special issue focuses on "the evolution, development, and functional morphology of the nasopharynx and its boundaries." Topics covered here include evolutionary developmental biology (or evo-devo), nasopharyngeal adaptions in bats, the importance of the nasopharynx and adjacent structures over the course of human evolution, normal development, middle ear morphology, clinical importance, and the study of the nasopharynx throughout history. Contributions to this special issue range among reviews and syntheses, descriptive analyses, phylogenetic analysis, traditional morphometrics, three-dimensional geometric morphometrics, and computational fluid dynamics. Here, we discuss the central importance of the nasopharynx as can be seen through vertebrate paleontology and comparative morphology. It is via the composite evolutionary history of the nasopharyngeal boundaries that our origins may be better understood, starting with the derivation of the choanae from the median olfactory pit of jawless fish nearly half a billion years ago to the basicranial flexion and facial reduction that distinguish Homo sapiens from all other living mammals. Indeed, the nasopharynx must be acknowledged for its importance in the processes of encephalization and acquisition of speech that have become the hallmark of our species.

Nasopharyngeal morphology contributes to understanding the "muddle in the middle" of the Pleistocene hominin fossil record.

The late archeologist Glynn Isaac first applied the term "muddle in the middle" to a poorly understood period in the Middle Pleistocene human fossil record. This study uses the nasopharyngeal boundaries as a source of traits that may inform this unclear period of human evolution. The nasopharynx lies at the nexus of several vital physiological systems, yet relatively little is known about its importance in human evolution. We analyzed a geographically diverse contemporary Homo sapiens growth series (n = 180 adults, 237 nonadults), Homo neanderthalensis (La Chapelle aux Saints 1, La Ferrassie 1, Forbes Quarry 1, Monte Circeo 1, and Saccopastore 1), mid-Pleistocene Homo (Atapuerca 5, Kabwe 1, Petralona 1, and Steinheim 1), and two Homo erectus sensu lato (KNM-ER 3733 and Sangiran 17). Methods include traditional (Analysis 1) and 3D geometric morphometric analysis (Analysis 2). H. erectus exhibited tall, narrow nasopharyngeal shape, a robust, ancestral morphology. Kabwe 1 and Petralona 1 plotted among H. sapiens in Analysis 2, exhibiting relatively shorter and vertical cartilaginous Eustachian tubes and vertical medial pterygoid plates. Atapuerca 5 and Steinheim 1 exhibited horizontal vomeral orientation similar to H. neanderthalensis, indicating greater relative soft palate length and anteroposterior nasopharynx expansion. They may exhibit synapomorphies with H. neanderthalensis, supporting the accretionary hypothesis. Species-level differences were found among H. sapiens and H. neanderthalensis, including relatively longer dilator tubae muscles and extreme facial airorhynchy among Neanderthals. Furthermore, H. neanderthalensis were autapomorphic in exhibiting horizontal pterygoid plate orientation similar to human infants, suggesting that they may have had inferiorly low placement of the torus tubarius and Eustachian tube orifice on the lateral nasopharyngeal wall in life. This study supports use of osseous nasopharyngeal boundaries both for morphological characters and understanding evolution of otitis media susceptibility in living humans.

Cadaveric Classification of the Genicular Arteries, with Implications for the Interventional Radiologist.

PURPOSE: To document and assess the genicular arterial variation in a large multicenter cadaveric sample and to generate an anatomical classification with implications for genicular artery embolization (GAE). MATERIALS AND METHODS: A total of 212 dissected donor body lower limbs from 3 medical school institutions were included. The descending genicular artery (DGA), superior lateral genicular artery, superior medial genicular artery, middle genicular artery, inferior lateral genicular artery, inferior medial genicular artery, and anterior tibial recurrent artery were identified for gross anatomical appearance, location of origin, diameter of vessels, and variation in branching patterns. RESULTS: A total of 198 DGAs, 204 popliteal-origin genicular arteries, and 183 anterior tibial recurrent arteries were adequately preserved and reviewed. Three types (A: 26%, B: 71%, and C: 5%) of DGA branching patterns were proposed along with 6 types (I: 28%, II: 22%, III: 15%, IV: 15%, V: 10%, and VI: 6%) of popliteal-origin genicular artery branching variants. Right versus left comparisons did not reveal clinically significant differences in the vessel distance (P = .30 to .82). CONCLUSIONS: Despite the large number of possible anatomical variations of the genicular arteries, 6 main patterns corresponded to >96% of the cases. The description and classification of the genicular arterial anatomy may provide useful information to the interventional radiologist and add to the technical nuances of GAE.

Quantitative Prediction of the Location of Carotid Bifurcation and Neurovascular Structures in the Carotid Region: A Cross-Sectional Cadaveric Study.

INTRODUCTION: The carotid region is encountered in vascular and neurological surgery and carries a potential for vascular and cranial nerve trauma. The carotid bifurcation is an especially important landmark and difficult to predict based on currently established landmarks. This study is a detailed analysis of the carotid region and proposes a novel methodology to predict the height of the bifurcation. MATERIALS AND METHODS: Superficial and deep dissections were performed on the anterior triangle of the neck to expose the carotid region in twenty-one formalin-fixed donor cadavers. Musculoskeletal and neurovascular structures were assessed in relation to the carotid bifurcation and the medial border of the clavicle (MBC). RESULTS: The carotid bifurcation occurred, on average, 11.4 mm higher on the left (p < 0.001; 95% CI: 9.28, 13.54). The superior thyroid artery (p < 0.001), facial vein (p < 0.001), and cranial nerve XII (p < 0.001) were all more distal on the left side when measured from the MBC while the angle of the mandible and stylohyoid muscle remained symmetric. Left- and right-sided vascular structures were symmetric when measured from the carotid bifurcation. CONCLUSIONS: Neurovascular structures within the carotid region are likely to be anatomically superior on the left side while vessels are likely to remain symmetric in relation to the carotid bifurcation. When measured from the MBC, the bifurcation height can be predicted by multiplying the distance between the MBC and mastoid process by 0.65 (right side) or 0.74 (left side). This novel methodological estimation may be easily learned and directly implemented in clinical practice.

Identification of critical windows in early development of human upper respiratory tract and middle ear disease.

Otitis media (OM) or middle ear disease is a prevalent pediatric condition generally related to early growth of the cartilaginous Eustachian tube (CET). This study used a developmental series of dry crania to reconstruct CET and dilator tubae (DT, the muscle opening the CET) morphology. Timing and directionality of CET and upper respiratory tract (URT) growth were investigated. Traditional and 3D geometric morphometrics (GM) were used to assess bony landmarks on the crania. The series was divided using dental eruption into seven growth stages ranging from before eruption of deciduous dentition (approximately the first 6 postnatal months) to eruption of the first permanent maxillary molar (after approximately 6 years). Bony endpoints of the CET and DT were used to calculate their morphology. GM analysis showed substantial shape differences between newborns, early infants, and all later developmental stages. Univariate measures showed the largest growth change between birth and 6 months. Subsequently, CET morphology changed little in the latter half of year 1, instead maturing gradually until approximately 3 years whereas DT relative length and orientation finish growth by the end of year 1. Incongruence in slower CET growth and faster DT growth could impact CET function between 6 and 12 months and be a contributing factor of OM. Tubal aeration may improve after this time when both CET and DT morphology mature, coinciding with clinically reported drop-off in ear infections.

Reconstructing the Neanderthal Eustachian Tube: New Insights on Disease Susceptibility, Fitness Cost, and Extinction.

Neanderthals are among the best studied and yet most enigmatic fossil human groups with aspects of their anatomy and functional morphology remaining poorly understood. We present the first anatomical reconstruction of the Neanderthal cartilaginous Eustachian tube (CET), a vital component of the upper respiratory tract and nexus for the middle ear and postnasal airway. The Eustachian (auditory, pharyngotympanic) tube, comprised of a bony and cartilaginous (CET) portion, is integral to normal physiological functions such as middle ear aeration and pressure equilibration. Findings indicate that Neanderthal tubal morphology may have predisposed them to high rates of middle ear disease (otitis media [OM]). In living humans, mechanical CET dysfunction underlies OM in infants and young children, with sequelae including hearing loss, meningitis, and pneumonia. Despite proven linkage of CET malfunction with OM, the role of CET morphology in Neanderthal health and disease remains unstudied. We reconstructed Neanderthal CET morphology, comparing their crania to a modern human growth series. Methods included geometric morphometrics and univariate measures among Procrustes-fitted coordinates. Results showed Neanderthal adults exhibiting primitively tall and narrow nasopharynges with infant-like horizontal CET and choanal orientation. As horizontal CET orientation is associated with increased OM incidence in infants and children until around age six, its appearance in Neanderthal adults strongly indicates persistence of high OM susceptibility at this time. This could have compromised fitness and disease load relative to sympatric modern humans, affecting Neanderthals' ability to compete within their ecological niche, and potentially contributing to their rapid extinction. Anat Rec, 302:2109-2125, 2019. © 2019 American Association for Anatomy.

The Nasal Complex of a Semiaquatic Artiodactyl, the Moose (Alces alces): Is it a Good Evolutionary Model for the Ancestors of Cetaceans?

Among Cetartiodactyla, cetaceans are the only obligate aquatic dwellers. Given morphological similarities between cetacean relatives such as Indohyus (the best represented Eocene raoellid artiodactyl) with other, later artiodactyls, any crown artiodactyl that engages in aquatic behaviors is of interest as an evolutionary model for the adaptations that accompanied the origins of cetaceans. The American moose (Alces alces) is the only non-cetacean artiodactyl to engage in aquatic foraging and, other than Hippopotamus, is distinctive in its diving behaviors. This study surveyed the soft and hard tissue nasal morphology of Alces alces to assess phylogenetic polarity and the presence of adaptations for diving and feeding in fresh water habitats. A fresh dissection of the facial musculature and nasal cavity was performed on one subadult male individual and osteological analyses were also performed on dry crania. This species was analyzed alongside fossil crania of Cervalces (its presumed ancestor), other cervids (e.g., Odocoileus virginianus, the white tail deer; Dama dama, the fallow deer), a bovid (Bos taurus, domestic cattle), and a carnivoran (Ursus americanus, the American black bear). A fresh dissection of the facial musculature and nasal anatomy of one fallow deer specimen was also performed for comparison with the moose. Results indicate that Alces alces exhibited a primitive configuration of maxillolabial muscles and, like Dama, exhibited a series of subcutaneous fibrous tissues connecting these muscles to skin. Alces and Dama, however, both exhibited autapomorphies in the soft tissue anatomy of the external nares. The former possessed a series of muscles that act to constrict the anterior nares, likely during diving. Extremely large fibrofatty pads that were perforated by muscle tendon supported their alar fold. Internally, a double-scrolled maxilloturbinal occupied nearly the entire volume of the anterior nasal cavity and protruded beyond the rim of the piriform aperture in dry crania. Dama had long, thin muscles taking origin on their nasal conchae and inserting onto the alar fold. Yet, despite these anterior nasal autapomorphies, the ethmoturbinal patterns of all observed cervids and the one bovid all appeared primitive with a posteroinferiorly oriented array of ethmoturbinals in close contact with a relatively straight cribriform plate, a macrosmatic condition. These differed from the curved cribriform plate of Ursus whose posterior nasal anatomy appeared hyper-macrosmatic. Indohyus exhibits no skeletal sign of a fleshy proboscis such as an enlarged piriform aperture or shortened nasal bones. Thus, there is little evidence that the early ancestors of cetaceans engaged in prolonged bouts of diving for aquatic foods but more probably were surface swimmers traveling between terrestrial food sources or fleeing predators. Anat Rec, 2018. © 2018 Wiley Periodicals, Inc. Anat Rec, 302:667-692, 2019. © 2018 Wiley Periodicals, Inc.

Cranial Indicators Identified for Peak Incidence of Otitis Media.

Acute otitis media (AOM) is one of the most common pediatric conditions worldwide. Peak age of occurrence for AOM has been identified within the first postnatal year and it remains frequent until approximately six postnatal years. Morphological differences between adults and infants in the cartilaginous Eustachian tube (CET) and associated structures may be responsible for development of this disease yet few have investigated normal growth trajectories. We tested hypotheses on coincidence of skeletal growth changes and known ages of peak AOM occurrence. Growth was divided into five dental eruption stages ranging from edentulous neonates (Stage 1) to adults with erupted third maxillary molars (Stage 5). A total of 32 three-dimensional landmarks were used and Generalized Procrustes Analysis was performed. Next, we performed principal components analysis and calculated univariate measures. It was found that growth change in Stage 1 was the most rapid and comprised the largest amount of overall growth in upper respiratory tract proportions (where time is represented by the natural logarithmic transformation of centroid size). The analysis of univariate measures showed that Stage 1 humans did indeed possess the relatively shortest and most horizontally oriented CET's with the greatest amount of growth change occurring at the transition to Stage 2 (eruption of deciduous dentition at five postnatal months, commencing peak AOM incidence) and ceasing by Stage 3 (approximately six postnatal years). Skeletal indicators appear related to peak ages of AOM incidence and may contribute to understanding of a nearly ubiquitous human disease. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1721-1740, 2017. © 2017 Wiley Periodicals, Inc.

Toward Understanding the Mammalian Zygoma: Insights From Comparative Anatomy, Growth and Development, and Morphometric Analysis.

The zygoma, or jugum, is a cranial element that was present in Mesozoic tetrapods, well before the appearance of mammals. Although as an entity the zygoma is a primitive retention among mammals, it has assumed myriad configurations as this group diversified. As the zygoma is located at the intersection of the visual, respiratory, and masticatory apparatuses, it is potentially of great importance in systematic, phylogenetic, and functional studies focused on this region. For example, the facial component of the zygoma and its contribution to a postorbital bar (POB) appear to be relevant to the systematics of a number of mammalian subclades, and the formation of a bony postorbital septum (POS) that separates the orbit from the infratemporal fossa is unique to, and thus potentially phylogenetically significant for uniting anthropoid primates, while the zygoma itself appears to serve to resist tension and bending forces during mastication. In order to better understand the zygoma in the context of its contributions to the circumorbital region, we documented its morphological expression in specimens representing 10 orders of mammals. Since the presence of a POB and of a POS has long been used to justify uniting extant primates and anthropoid primates as respective clades, and because postorbital closure (POC) is morphologically more complex than a POB, we provide detail necessary to address these claims. Our taxically broad overview also allowed us to provide for the first time definitions of configurations that can be applied to future studies. Using a different, but also taxically broad sample of mammals, and of primates in particular, we performed two geometric morphometric analyses that were geared toward testing long-held interpretations of the functional role of the zygoma, especially with regard to mastication and in the context of orbital frontation (to which the zygoma contributes). Further, overall, zygomatic morphology tends not to scale with allometry, sexual dimorphism, or angle of orbital convergence, but it does contribute to unique patterns of intraspecies variation. Anat Rec, 300:76-151, 2017. © 2016 Wiley Periodicals, Inc.

CT Examination of Nose and Paranasal Sinuses of Egyptian Mummies and Three Distinct Human Population Groups: Anthropological and Clinical Implications.

The interaction of nasal morphology and climatic conditions has resulted in diverse hard- and soft-tissue configurations across human population groups. While the processes of skull pneumatization are not fully understood, the invasions of the paranasal sinuses [PNS] into the cranium have contributed to assorted morphologies. Human migratory patterns and the strong association with climatic variables through time and space may explain this diversity. This study examined four multiregional populations of which two are from Egypt but of widely divergent eras. Three Egyptian mummies [EG-M] from the middle kingdom were CT scanned providing a unique opportunity to investigate the status of PNS anatomy within a time frame from 1567 BCE to 600 CE and compare it to a contemporary Egyptian [EG] (n = 12) population. Dry skulls of Inuit [IT] (n = 10) and East African [EA] (n = 8) provide out-group comparisons, as one group represents an isolated geographic environment far different from that of Egypt and the other group inhabiting distinct environmental conditions albeit located within the same continent. Results showed EG-M and EG frontal sinus volumes were diminutive in size with no statistically significant difference between them. Maxillary sinus size values of EG-M and EG clustered together while IT and EA significantly differed from each other (P = 0.002). The multiregional groups exhibited population specific morphologies in their PNS anatomy. Ecogeographic localities revealed anatomical differences among IT and EA, while the potential time span of about 3,500 years produced only a negligible difference between the Egyptian groups. The small sample sizes incorporated into this research requires confirmation of the results by analyses of larger samples from each geographic region and with the integration of a larger group of Egyptian mummified remains.

The nasal complex of Neanderthals: an entry portal to their place in human ancestry.

Neanderthals are one of the most intensely studied groups of extinct humans, as aspects of their phylogeny and functional morphology remain controversial. They have long been described as cold adapted but recent analyses of their nasal anatomy suggest that traits formerly considered adaptations may be the result of genetic drift. This study performs quantitative and qualitative analysis of aspects of the nasal complex (NC) in Neanderthals and other later Pleistocene fossils from Europe and Africa. A geographically diverse sample of modern human crania was used to establish an anatomical baseline for populations inhabiting cold and tropical climates. Nasofrontal angle, piriform aperture dimensions, and relative maxillary sinus volume were analyzed along with qualitative features of the piriform aperture rim. Results indicate that Neanderthals and other later Pleistocene Homo possessed NC's that align them with tropical modern humans. Thus comparison of Neanderthal nasal morphology with that of modern humans from cold climates may not be appropriate as differences in overall craniofacial architecture may constrain the narrowing of the piriform apertures in Neanderthals. They retain primitively long, low crania, large maxillary sinuses, and large piriform aperture area similar to mid-Pleistocene Homo specimens such as Petralona 1 and Kabwe 1. Adaptation to cold climate may have necessitated other adaptations such as bony medial projections at the piriform aperture rim and, potentially, midfacial prognathism. Nasal complex components of the upper respiratory tract remain a critical but poorly understood area that may yet offer novel insight into one of the greatest continuing controversies in paleoanthropology.

Supplemental cross-linking in tissue-based surgical implants for abdominal wall repair.

BACKGROUND: There are a number of commercially available tissue-based surgical implants for use in repairing abdominal wall defects. The role and effect of supplemental cross-linking present in some of these implants has been questioned and evaluated in a number of recent experiments. In this review we summarize results of preclinical animal studies evaluating tissue-based surgical implants used for abdominal wall repair with a focus on currently available products and the influence of supplemental cross-linking. METHODS: A search of PubMed, MEDLINE and article reference lists was undertaken. Inclusion criteria were animal studies, abdominal wall hernias, and studies reporting on the main outcomes of tensile strength, susceptibility to enzymatic degradation, antigenicity and immunogenicity, foreign body reaction, tissue ingrowth, and complications. Exclusion criteria included those studies that only reported on methods of fixation, implantation or fenestration of mesh. RESULTS: A total of 21 articles that specifically compared non-cross-linked and supplemental cross-linked tissue-based implants were reviewed. In addition, other studies that compared tissue-based implants, which are not commercially available, were included where appropriate. CONCLUSION: Supplemental cross-linking of collagen found in tissue-based surgical implants has not been shown to adversely affect the strength of the implant or its ability to support long-term ingrowth of tissue. Further studies need to be performed to determine if the differences in cross-linked and non-cross-linked implants observed in animal models translate to differences in clinical performance.

[Method to calculate the additional hospital stay in patients with cross infection]. / Estimación de la estancia adicional en pacientes con infección hospitalaria.

OBJECTIVE: To calculate additional hospital stay due to specific cross infection. METHODS: Cases and controls study; matched by age +/- 2 years, sex, specialty in which were taken care, diagnosis, surgical procedure and hospitalization stay, between July 2005-June 2006. ANALYSIS: t test, chi(2) to calculate death risk, Kaplan-Meier analysis to calculate survival, Hosmer-Lemeshow test to know the contribution of cross infection for additional hospital stay due to cross infection (AHSDCI). RESULTS: We identified 851 patients with 1347 cross infection in 16 528 discharges. We could match 677. The cases stayed 25.42 days and the controls 13.29 (p < 0.01). The death risk for the cases was 5.8 (CI 95 % = 3.7-8.6, p < 0.01), four weeks survival 55.3 % for cases and 79.2 % for the controls. The AHSDCI for pneumonia was 10.39 days, urinary-tract-infection 6.28, bacteremia 8.92, vascular-catheter-related infection 3.31, surgical site infections 7.42, and skin and soft-tissue-infection 3.31 (p < 0.05). CONCLUSIONS: We used a multivariate model fitted to patient's gravity and complexity to extract the proportion days of AHSDCI of each cross infection.

The paranasal sinuses: the last frontier in craniofacial biology.

This special issue of the Anatomical Record explores the presence and diversity of paranasal sinuses in distinct vertebrate groups. The following topics are addressed in particular: dinosaur physiology; development; physiology; adaptation; imaging; and primate systematics. A variety of approaches and techniques are used to examine and characterize the diversity of paranasal sinus pneumatization in a wide spectrum of vertebrates. These range from dissection to histology, from plain X-rays to computer tomography, from comparative anatomy to natural experimental settings, from mathematical computation to computer model simulation, and 2D to 3D reconstructions. The articles in this issue are a combination of literature review and new, hypothesis-driven anatomical research that highlights the complexities of paranasal sinus growth and development; ontogenetic and disease processes; physiology; paleontology; primate systematics; and human evolution. The issue incorporates a wide variety of vertebrates, encompassing a period of over 65 million years, in an effort to offer insight into the diversity of the paranasal sinus complexes through time and space, and thereby providing a greater understanding and appreciation of these special spaces within the cranium.

Development of the ethmoid sinus and extramural migration: the anatomical basis of this paranasal sinus.

Frontal and/or maxillary sinusitis frequently originates with pathologic processes of the ethmoid sinuses. This clinical association is explained by the close anatomical relationship between the frontal and maxillary sinuses and the ethmoid sinus, since developmental trajectories place the ethmoid in a strategic central position within the nasal complex. The advent of optical endoscopes has permitted improved visualization of these spaces, leading to a renaissance in intranasal sinus surgery. Advancing patient care has consequently driven the need for the proper and accurate anatomical description of the paranasal sinuses, regrettably the continuing subject of persistent confusion and ambiguity in nomenclature and terminology. Developmental tracking of the pneumatization of the ethmoid and adjacent bones, and particularly of the extramural cells of the ethmoid, helps to explain the highly variable adult morphology of the ethmoid air sinus system. To fully understand the nature and underlying biology of this sinus system, multiple approaches were employed here. These include CT imaging of living humans (n = 100), examination of dry cranial material (n = 220), fresh tissue and cadaveric anatomical dissections (n = 168), and three-dimensional volume rendering methods that allow digitizing of the spaces of the ethmoid sinus for graphical examination. Results show the ethmoid sinus to be highly variable in form and structure as well as in the quantity of air cells. The endochondral bony origin of the ethmoid sinuses leads to remarkably thin bony contours of their irregular and morphologically unique borders, making them substantially different from the other paranasal sinuses. These investigations allow development of a detailed anatomical template of this region based on observed patterns of morphological diversity, which can initially mask the underlying anatomy. For example, the frontal recess, ethmoid infundibulum, and hiatus semilunaris are key anatomical components of the ethmoid structural complex that are fully documented and explained here on the basis of the template we have developed, as well as being comprehensively illustrated. In addition, an exhaustive 2000-year literature search identified original sources of nomenclature, in order to help clarify the persistent confusions found in the literature. Modified anatomical terms are suggested to permit proper description of the ethmoid region. This clarification of nomenclature will permit better communication in addition to eliminating redundant terminology. The combination of anatomical, evolutionary, and clinical perspectives provides an important strategy for gaining insight into the complexity of these sinuses.

Climatic effects on the nasal complex: a CT imaging, comparative anatomical, and morphometric investigation of Macaca mulatta and Macaca fascicularis.

Previous studies exploring the effects of climate on the nasal region have largely focused on external craniofacial linear parameters, using dry crania of modern human populations. This investigation augments traditional craniofacial morphometrics with internal linear and volumetric measures of the anatomic units comprising the nasal complex (i.e., internal nasal cavity depth, maxillary sinus volumes). The study focuses on macaques (i.e., Macaca mulatta and Macaca fascicularis) living at high and low altitudes, rather than on humans, since the short residency of migratory human populations may preclude using them as reliable models to test the long-term relationship of climate to nasal morphology. It is hypothesized that there will be significant differences in nasal complex morphology among macaques inhabiting different climates. This study integrated three different approaches: CT imaging, comparative anatomy, and morphometrics-in an effort to better understand the morphological structure and adaptive nature of the nasal complex. Results showed statistically significant differences when subsets of splanchnocranial and neurocranial variables were regressed against total maxillary sinus volume for particular taxa. For example, basion-hormion was significant for M. fascicularis, whereas choanal dimensions were significant only for M. mulatta. Both taxa revealed strong correlation between sinus volume and prosthion to staphylion distance, which essentially represents the length of the nasal cavity floor-and is by extension an indicator of the air conditioning capacity of the nasal region. These results clearly show that climatic effects play a major role in shaping the anatomy of the nasal complex in closely related species. The major influence upon these differing structures appears to be related to respiratory-related adaptations subserving differing climatic factors. In addition, the interdependence of the paranasal sinuses with other parts of the complex strongly indicates a functional role for them in nasal complex/upper respiratory functions.

Características clínico-epidemiológicas de pacientes con cólera en la ciudad de México / Clinical and epidemiological characteristics of cholera patients in Mexico City

Objetivo. Comparar las características clínico-epidemiológicas de enfermos de cólera (casos) con las de pacientes con diarrea por otra causa (no casos), atendidos en las unidades médicas de la Delegación 2 Noreste del Distrito Federal, del Instituto Mexicano del Seguro Social (IMSS). Material y métodos. Se realizó un estudio transversal analítico y se utilizaron datos de 4 952 notificaciones reunidads entre 1995 y 1998 a través del formato oficial "Hoja de notificación inmediata de casos de cólera", que cada unidad médica envía a la Coordinación de Salud Comunitaria del IMSS. Mediante estadística analítica se compararon medias y proporciones para ambos grupos. Resultado. Se identificaron 588 pacientes con cólera y 4364 con diarrea por otra causa. En el primer grupo, la edad promedio varió entre los 39 y los 51 años, y predominó el sexo femenino (54 por ciento). Durante 1995 y 1997 (años en los que se presentó un número más elevado de casos), los pacientes de cólera, en relación con el grupo de comparación, presentaron una mayor frecuencia de evacuaciones líquidas (97 vs. 73 por ciento), con aspecto de "agua de arroz" (31 vs. 13 por ciento), vómitos (72 vs. 63 por ciento), espasmos muclares (49 vs. 26 por ciento), deshidratación (83 vs. 71 por ciento), choque hipovolémico (10 vs. 1 por ciento) y defunciones (0.85 vs 0.25 por ciento 9; con diferencias estadísticamente significativas. Conclusiones. El cólera muestra un comportamiento cíclico bianual, a mayor frecuencia mayor gravedad de la enfermedad. Se requiere incrementar la vigilancia epidemiológica y el esfuerzo médico para un diagnóstico y tratamiento oportuno