Growth pattern of the maxillary sinus in the miniature pig (Sus scrofa)

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.

Frontal sinus ontogeny and covariation with bone structures in a modern human population

In humans, the frontal sinus (FS) is located in the medial part of the supraorbital region, sometimes expanded throughout the frontal squama. It exhibits high morphological variability, but its general form appears to be constrained by surrounding structures. The goal of this study is to analyze FS growth and test for covariation between FS volume and the glabellar region, upper nasal region, bone thickness and endocranial size in a human sample from Argentina. The sample comprises 149 reconstructions derived from computed tomography images of individuals aged 0-31 years. Volume of the FS and measurements of the surrounding structures were recorded. The FS growth trajectory was assessed by parametric and nonparametric methods, and covariation was determined using correlations and partial correlations. The FS volume could be measured at an age of about 6 years and older; adults had no aplasia but hyperplasia was found in some cases. Since the most conspicuous characteristic found was variation among individuals, the nonparametric smoothing spline produced very poor fitting. The modified logistic function was the only parametric method providing significant parameters. Sexes differed in the age at which FS growth began and ended, with FS developing earlier but at a slower rate in females than in males. The FS volume did not correlate with either upper nasal width or endocranial volume, but it correlated with bone thickness measurements (mainly from the glabellar region), even when age was held constant. Expansion of the FS at the frontal poles also correlated with frontal bone thickness. Despite the difficulty in modeling and predicting the trajectory and morphology of FS, our results suggest that it is affected by its surrounding bony environment.

An animal model for sinus floor elevation with great elevation heights. Macroscopic, microscopic, radiological and micro-CT analysis: ex vivo

OBJECTIVES

Different animal models are used for research and training concerning sinus floor elevation. However, there is little information regarding an animal model for elevation heights of approximately 10 mm. The aim of this study was to explore the anatomical aspects of the maxillary sinus of adult pigs and to investigate the suitability of this animal as a model for sinus floor elevation training and research with great elevation heights.

MATERIAL AND METHODS

Thirty-four bisected heads of adult domestic pigs were examined 6 h postmortem. Direct sinus floor elevation was performed with an elevation height of 10 mm. Localization, diameters, volume and septa of the maxillary sinus were recorded on lateral X-rays and macroscopically. The thickness and structure of the maxillary sinus were investigated microscopically. The osseous microstructure of the lateral sinus wall was assessed microscopically and via micro-CT.

RESULTS

The maxillary sinus of the adult pig exhibits an average length of 51±6.2 mm, a height of 31±4.1 mm, a width of 19±1.6 mm and a volume of 31±7.6 cm(3) . At least one septum could be observed on the floor of each sinus. The mucosal thickness amounted to a mean of 1692±138 μm, and the lateral bony wall of the sinus to a mean of 3±0.3 mm. A laceration of the Schneiderian membrane occurred in 25% during the elevation process.

CONCLUSION

The maxillary sinus of adult domestic pigs is a suitable model for sinus floor elevation training and research with greater elevation heights of up to 10 mm.

Morphology, constraints, and scaling of frontal sinuses in the hartebeest,Alcelaphus buselaphus (Mammalia: Artiodactyla, Bovidae)

The frontal sinuses of bovid mammals display a great deal of diversity, which has been attributed to both phylogenetic and functional influences. In-depth study of the hartebeest (Alcelaphus buselaphus), a large African antelope, reveals a number of previously undescribed details of frontal sinus morphology. In A. buselaphus, the frontal sinuses conform closely to the shape of the frontal bone, filling nearly the entire element. However, the horncores are never extensively pneumatized, contrasting with the condition seen in many other bovids. This evidence is inconsistent with the hypothesis that sinuses are opportunistic pneumatizing agents, suggesting that phylogenetic factors also play a role in determining sinus size. Both cranial sutures and neurovasculature appear to constrain the growth of sinuses in part. In turn, the sinus also affects the growth of the parietal; apparently this element is not truly pneumatized by the sinus in most cases, but the bone's shape changes under the influence of the sinus. Furthermore, the sinuses present relatively few struts when compared with the sinuses of some other bovids, such as Ovis. By adapting methods previously developed for measuring structural parameters of trabecular bone, it is possible to quantify certain aspects of sinus morphology. These include the number of bony struts within the sinus, the spacing of these struts, and the size of individual cavities within the sinus. Some differences in the number of struts are evident between subspecies. Similarly, significant differences occur in the relative number of struts between male and female A. buselaphus, which may be related to behavior. The volume of the sinus is strongly correlated with the size of the frontal, but less so with overall cranial size. This finding illustrates the importance of choosing variables carefully when comparing sinus sizes and growth between species.