Orbital shape in goat and sheep: Symmetric analysis

The aim of this study is to evaluate orbital symmetry in goat and sheep skulls. For this purpose, a total of 83 skulls, including 50 sheep and 33 goat skulls, were used in the study. Geometric morphometry method was applied. For symmetric analysis, one side of each orbit was photographed twice and mirror images were created. There were 36 landmards marked to determine the outer limit of the orbita. As a result of the study, asymmetric components (fluctuating asymmetry and directional asymmetry) for shape were statistically significant in both goats and sheep (p < 0.0001). The first three principal components explained 52.558% of the total shape variation in goats and 61.245% in sheep. This value for symmetric components was 59.095% and 67.742% for goats and sheep, respectively, and 66.791% and 71.154% for asymmetric components. As a result of discriminant function analysis, right and left orbital shapes showed grouping characteristics with similar success rates according to species. Although limited, the right orbit in goats (100%) and the left orbit in sheep (96.5%) were grouped more accurately.

Orbital shape in sheep and goats with sex and breed factors

The purpose of this study was to identify the dimorphic structures of the orbita based on breed and sex factors through shape analysis across species. Additionally, the study aimed to ascertain the variability between the two species. A total of 86 (51 sheep-Akkaraman [Ak] and Morkaraman [Mk], 35 goats-Hair [Hr] and Honamlı [Hm]) skulls were used in the study. It was decided to designate 36 landmarks to represent the orbit's edge. In the principal component analysis, 68 PCs were calculated. It was determined that PC1, PC2 and PC3 explained the total variance in morphology by 26.909%, 16.147% and 13.616%, respectively. According to the cross-validation results, the goats were grouped with 95% (Hm: 100%, Hr: 90%), while the sheep were grouped with 56% (Ak: 50%, Mk: 63%). Therefore, dimorphism among goat breeds on orbita shape was more pronounced compared to sheep. In the discriminant function analysis of the sex groups, Procrustes and Mahalanobis distance values in goats were 0.04425425 (p < 0.0001) and 5.3733 (p = 0.9550), in sheep 0.03513424 (p < 0.0001) and 7.1003 (p = 0.9414), respectively, was detected. According to the cross-validation results, in terms of sex, goats were correctly grouped at a rate of 74% (F: 73%; M: 75%) and sheep breeds were correctly grouped at a rate of 72% (F: 77%; M: 66%). Factors such as habitat selection, breeding behaviours and ecological environment may show anatomical differences within breeds as well as between breeds. Therefore, various measurement techniques are used to reveal these differences. As a result, it is thought that the study will contribute to many disciplines, especially taxonomy and zooarchaeology, by analysing the shape of the orbita of sheep and goat breeds, the domestication of which dates back to ancient times, and revealing the similarities and differences between species and according to sex.

Quantification of global orbital shape variation

The complex anatomy of the orbit generates a complex orbital shape that can only be quantified approximatively by classic linear measurements such as maximum width and height. There is no global three-dimensional quantification of variations in orbital shape. The purpose of this study was to develop a method to quantify a global three-dimensional orbital shape variation in a healthy population and to test a series of explanatory factors. We investigated the hypotheses that orbital shape is related to gender(H1), orbital size(H2) and/or age(H3). Medical computed tomography(CT) images of 60 adult individuals were studied. The study sample consisted of 30 males and 30 females with a mean age of 25.1 years. Four anatomical landmarks and 140 semi-landmarks were measured on both positive and negative 3D reconstructed orbits and analyzed with geometric morphometrics. A principal component analysis(PCA) was computed to define a morphological space. Shape variation was visualized using vector distance maps and diagrams. The greatest variation was seen in the length of the superior orbital fissure. There was a gradient in terms of orbital shape ranging from short, wide orbits to tall, narrow orbits. The analysis did not highlight any significant age-, gender- or size-related impact in terms of orbital shape variation. Future avenues to explore include the study of other potential explanatory factors such as the different embryological origins of the orbital bones, the passage of vessels and nerves, and ethnic origins. This method can also be applied to the study of pathological orbits.

Anaesthetic considerations for the surgical management of ocular hypotony in adults

Ocular hypotony can occur from many causes, including eye trauma, ophthalmic surgery and ophthalmic regional anaesthesia-related complications. Some of these patients require surgical intervention(s) necessitating repeat anaesthesia. While surgical management of these patients is well described in the literature, the anaesthetic management is seldom discussed. The hypotonous eye may also have altered globe anatomy, meaning that the usual ocular proprioceptive feedbacks during regional ophthalmic block may be altered or lost, leading to higher risk of inadvertent globe injury. In an 'open globe' there is a risk of sight-threatening expulsive choroidal haemorrhage as a consequence of ophthalmic block or general anaesthesia. This narrative review describes the physiology of aqueous humour, the risk factors associated with ophthalmic regional anaesthesia-related ocular hypotony, the surgical management, and a special emphasis on anaesthetic management. Traumatic hypotony usually requires urgent surgical repair, whereas iatrogenic hypotony may be less urgent, with many cases scheduled as elective procedures. There is no universal best anaesthetic technique. Topical anaesthesia and regional ophthalmic block, with some technique modifications, are suitable in many mild-to-moderate cases, whilst general anaesthesia may be required for complex and longer procedures, and severely distorted globes.

Examination of Shape Variation of the Skull in British Shorthair, Scottish Fold, and Van Cats

A variety of skull shapes are frequently used for discrimination between animal species, breeds, and sexes. In this study, skulls of three different breeds of cats were examined by the geometric morphometric method, with the aim of revealing skull shape differences. For this purpose, 27 cats (6 British Shorthair, 7 Scottish Fold, and 14 Van cats) were used. The skulls of cats were modeled by computed tomography. Geometric morphometrics was applied using dorsal (8 landmarks, 63 semilandmarks) and lateral (8 landmarks, 63 semilandmarks) skull projections on these models. Centroid size differences between the breeds were statistically insignificant. However, the differences in shape were statistically significant for both the dorsal view and lateral view. Shape variation was less in the British Shorthair than in other breeds. Shape differences generally occurred around the orbit. In the skull of Scottish Folds, the orbit was situated more caudally than in other breeds. The British Shorthair had the largest orbital ring. In dorsal view, the Scottish Fold had the largest orbital diameter. The orbital ring of Van cats was smallest in both dorsal and lateral views. In the canonical variate analysis, it was seen that the breeds were separated from each other. The shape difference in the skull between different cat breeds could be revealed by geometric morphometrics. The results of this study provide useful information for taxonomy.

Radiologic Assessment of Orbital Dimensions among Omani Subjects: A computed tomography imaging-based study at a single tertiary centre

Objectives

This study aimed to determine the orbital dimensions of Omani subjects who had been referred for computed tomography (CT) of the brain at Sultan Qaboos University Hospital, Muscat, Oman. Good knowledge of the normal orbital dimensions is clinically essential for successful surgical outcomes. Racial, ethnic and regional variations in the orbital dimensions have been reported.

Methods

A total of 273 Omani patients referred for CT scans of the brain were retrospectively evaluated using an electronic medical records database. The orbital dimensions were recorded using both axial and sagittal planes of CT images.

Results

The mean orbital index (OI) was found to be 83.25 ± 4.83 mm and the prevalent orbital type was categorised as the mesoseme. The mean orbital index was 83.34 ± 5.05 mm and 83.16 ± 4.57 mm in males and females, respectively, with their difference not being statistically significant (P = 0.76). However, a statistically significant association was observed between the right and left orbits regarding horizontal distance (P <0.05) and vertical distance (P <0.01) of orbit and OI (P <0.05). No significant difference between the OI and age groups was observed in males and females. The mean interorbital distance and interzygomatic distance were found to be 19.45 ± 1.52 mm and 95.59 ± 4.08 mm, respectively. These parameters were significantly higher in males (P <0.05).

Conclusion

Results of the present study provide reference values of orbital dimensions in Omani subjects. Mesoseme, a hallmark of Caucasian people, is discovered to be the prevalent orbital type of Omani subjects.

Differences in anthropometric measures of the orbit between Serbian and Roma populations of the Central Serbia

Introduction/Objectives. The shape and size of the orbital cavity are important parameters in planning surgical interventions and have significance in anthropology and forensic medicine. The aim of this study was to determine the morphometric characteristics of orbital cavity in Serbian population and to examine if there are differences in examined parameters between Serbs and the Roma Community of Serbia. Methods. Using computer tomography and subsequent multiplanar reconstruction we analyzed orbits from 76 Serbian and 18 Roma healthy volunteers. There was no significant difference in age between the ethnicities. Results. The height and width of the left orbit and the height of the right orbit were significantly higher in Roma group, whereas the width of the right orbit was not statistically different between ethnicities. Orbital indices, however, for both left and right orbit did not significantly differ between Serbian and Roma examinees. Right orbital volume did not differ between the groups, but left orbits had significantly larger volumes in Roma population. Finally, biorbital and interorbital width were both significantly higher in Roma than in Serbian examinees. We could not show differences between sexes except for the biorbital width, which had lower values in Serbian, but not Roma women than in men. Conclusion. Taken together, our results indicate larger orbits, as well as greater distances between the eyes in Roma than in Serbian examinees.

Developmental changes of the facial skeleton from birth to 18 years within a South African cohort (A computed tomography study)

Skeletal remains are often found on a crime scene in which a forensic anthropologist is then consulted to create a biological profile, which includes the estimation of age, sex, ancestry and stature. The viscerocranium plays an important role in the formation of a biological profile. However, to utilise the viscerocranium for age estimation, population specific normative data and knowledge of the development of the viscerocranium is required. Therefore, this study aimed to investigate the developmental changes from birth to 18 years of age of the facial skeleton of individuals from a South African cohort. This study comprised of 239 computed tomography (CT) scans (128 males; 111 females). The viscerocranium was subdivided into five regions viz.: orbital, nasal, midfacial, maxillary and mandibular. The linear parameters in each region were correlated to age to identify the developmental growth patterns of the viscerocranial regions according to male and female. The measurements which displayed the highest correlations with age were used to develop formulas which could be used for age estimation. The results of this study showed that the measurements in the orbital, midfacial, maxillary and mandibular regions experienced rapid growth between 0 and 5 years of age, with the nasal region increasing steadily over time. It was noted that males displayed overall larger measurements than females except for the anterior interorbital distance and both right and left zygomatic arch lengths (ZAL). Although only the left orbital height, nasal aperture height and mandible width displayed statistically significant size differences according to sex (p ≤ 0.05). The measurements which showed the highest correlations to age were the zygomatic arch distance (r = 0.8842, p < 0.001), ZAL (right: r = 0.8929, p < 0.001; left: r = 0.8656, p < 0.001) and the mandible width (r = 0.8444, p < 0.001). Formulas were derived for the measurements that could be used to forensically estimate age within a subadult cohort.

Morphometric Variations and Growth Analysis of the Side Face Profiles of Chinese Children

OBJECTIVE

We aim to use geometric morphometric methods to analyze the contours of the side face profile and its variations in 116 children in Hunan province, China, in order to reveal common morphological features and growth of the side face profiles of Chinese children.

DESIGN

We photographed the side faces with consistent standardized procedures. Thirty-seven landmarks were recorded, which comprehensively reflected the facial sagittal plane. The collection of coordinate data regarding landmarks was conducted by tpsDig software. Other analyses, such as average shape analysis, principal component analysis, variations analysis, and allometric analysis, were conducted using tpsRelw and tpsRegr.

RESULT

Based on the 37 landmarks, principal component analysis was used on the profiles of boys and girls. The result shows that PC1 and PC2 account for 35.46% and 27.44% of the side face contour variations, respectively. There is no significant difference in the side profiles of boys and girls. Overlapping distributions between the boys and girls occurred. A significant difference occurs when principal component analysis was used on the side profiles of children and adults.

CONCLUSIONS

There is a significant difference in the side face profiles between adult males and females. Adult males have a higher brow (the 8th landmark) than females, and adult females have a more curved forehead. However, the side face profiles of boys and girls around 10 years of age are generally similar, which suggests that the significant difference in side face profiles between adult males and females may be formed after the age of 10. This study is of great significance for both orthodontists and pediatricians to use different norms for kids and adults and different norms for males and females for each of those age groups.

Assessing zygomatic shape and size for estimating sex and ancestry in a South African sample

Unidentified, decomposed and skeletonised human remains are frequently found in South Africa, therefore, standardised, reliable and relevant sex and ancestry estimation methods are required for forensic identification. This study assessed sex and ancestral variation in zygomatic size and shape in a South African population using geometric morphometric analyses. The zygoma of 158 South African individuals were sampled. Eight zygomatic landmarks were captured in 3-dimensions using a Microscribe G2 digitiser and assessed using procrustean geometric morphometrics. Shape and size differences were analysed using multivariate linear regression, discriminant function and canonical variate analyses. Males had significantly larger zygomas than females. Significant shape variation was found between ancestral groups. Bantu-speaking and Mixed ancestry individuals had narrower, shorter and more anteriorly projecting orbital margins, whilst Europeans had vertically elongated and receded orbital margins. European ancestral groups were most discernible from Bantu-speakers and Mixed ancestral groups. Ancestry estimation accuracies improved when ancestry was aggregated with sex. Pairwise ancestry-linked comparisons in females were as follows; Bantu-speakers (76%) from Europeans (72%), Bantu-speakers (71%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (63%). Similarly, ancestry-linked comparisons in males were as follows; Bantu-speakers (77%) from Europeans (81%), Bantu-speakers (53%) from Mixed ancestry (59%) and European (72%) from Mixed ancestry (82%). Size differences are putatively linked to variations in hormone-regulated growth and muscular robusticity between males and females. Shape variations between ancestral groups are likely attributable to the heterogenous genetic and ancestral origins of the South African population. It is challenging to distinguish between South Africa Bantu speakers and Mixed ancestry people due to Mixed ancestry individuals having variable genetic contributions from Khoesan, Bantu-speakers, Europeans and Asians. Bantu-speaking and Mixed ancestry people had zygomatic morphologies consistent with historical thermoregulatory adaptations to sub-Saharan climates, reported in African-descendants. Zygomatic morphology in European descendants suggests ancestral origins from colder climatic regions. This study demonstrated the utility of the zygoma in distinguishing between ancestral groups in South Africa, but further research is required to develop population-specific standards to distinguish between South African populations with shared African ancestry. The zygoma shows a promising ability to estimate sex and ancestry in South Africans, suggesting population specific standards for this bone may be of forensic interest.

Morphometric Analysis of the Facial Profile: Contour of the Side Face and its Variations

Much research has been conducted on the morphological characteristics of the Chinese. However, very few facial measurements have been documented, especially of the side face. This study uses geometirc morphometric method to analyze the contour and variations of the side face in Bai and Yi ethnic minorities from Yunnan province, China. The mark collection proves that for the Bai ethnicity, the variations of the nose are comparatively large, while the forehead variations are small. Variations around the lips and the chin are the largest. For the Yi ethnicity, the forehead also witnesses small variations and the nose again has large variations. The area around the glabella has large variations. Through the comparisons, the area around the glabella tends to extrude more in males both in Bai and Yi. The situation, however, is much more different when it comes to the trichion landmark collection where we see an apparent intrusion in males. For the trichion, Yi people are more intruded than the Bai. Similarities between Bai and Yi are demonstrated by principal component analysis: one can roughly set the males apart from the females using the vertical axis. Profile at the end of horizontal axis suggests that the female facial profile has the following features: the nose is not so prominent as the male, the forehead and the nose are linked by an noticeable arc, the forehead is comparatively steep and is almost in a vertical plane with the lips and the chin. By comparison, the male has a flatter forehead, a more prominent nose, an obvious sellion, and an intruded chin. The common morphologic features of the Chinese face may be reflected through these similarities.

Radiologic evaluation of orbital index among Ghanaians using CT scan

Background

Orbital index (OI) expresses the proportion of the orbital height to the orbital width and varies with race, regions within the same race and periods in evolution. This index is useful in forensic medicine, anthropology and surgery. However, the average OI among Ghanaian adults was unknown.

Aim

The aim of this study was to determine the orbital index of adult Ghanaians and classify them under one of the three predetermined groups.

Method

The study design was a retrospective cross-sectional. A systematic random sampling method was used for selecting 350 adult Ghanaian head computed tomography images available from 1 January to 31 December 2015 at KBTH Hospital. The orbital height and orbital width of each orbit were measured on a 3D CT skull. Data was analysed using Microsoft Excel and Statistical Package for Social Sciences version 20.

Results

The study had more females than men (167, 47.71%, vs 183, 52.29%). The observed orbital index of Ghanaians in the study was 81.22 ± 4.22. The mean orbital index was 80.52 ± 4.66 in males and 82.15 ± 3.83 in females with their difference being statistically significant (p value <0.05). This placed both genders in the Microseme category of orbit. There was no significant difference between the orbital index of the two orbital sides (left and right orbits).

Conclusion

The study found Ghanaians in the category of the Microseme and also indicated a strong sexual dimorphism. The outcome of this study may be useful in forensic medicine for skull classification and also for better surgical approach in neurosurgery as well as cosmetic surgery.

A study of cranial variations based on craniometric indices in a South Indian population

BACKGROUND

Human skull has been the most extensively studied bone for establishing the taxonomies at evolutionary levels. Crania are also the most commonly used skeletal elements in population studies because they are known to be more genetically driven and less affected by environmental factors. The craniofacial indices are considered as clinical anthropometric parameters used in the investigation of craniofacial skeletal deformities and brain development. The present research is an attempt to study the cranial indices in the South Indian population.

METHODS

The sample for the study included 118 dry adult crania. All the osteometric measurements were taken using standard anthropometric instruments, and 3 indices, namely, cranial index, orbital index (OI), and index of foreman magnum (FMI), were calculated. Cranial index is calculated as (maximum cranial breadth / maximum cranial length) × 100, OI as (orbital height / orbital breadth) × 100, and FMI as (transverse diameter / anteroposterior diameter) × 100. The crania were further classified based on these indices.

RESULTS

The cranial index ranged between 66.67 and 85.71 (mean, 78.57 [SD, 4.11]), the OI ranged between 68.89 and 102.63 (mean, 84.23 [SD, 6.64]), and the FMI ranged between 68.57 and 96.88 (mean, 79.71 [SD, 6.98]). Cranial index did not show any significant correlation with the OI (r = -0.162, P = 0.081) or the FMI (r = -0.045, P = 0.626). A statistically significant correlation was, however, observed between OI and FMI (r = -0.232, P = 0.012).

CONCLUSIONS

The current study developed population-specific classification of crania using cranial indices. This craniometric baseline data pertaining to the craniofacial indices may be useful in presurgical planning and the postsurgical evaluation. It may also assist the forensic anthropologists in the categorization of human skulls, which may be an important component in identification of highly decomposed dead bodies and skeletal remains. More such studies need to be conducted to understand the effect of environment and genetics on the cranial shapes in different population groups.