Browsing by Subject "Anatomy"

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    An examination of the objective evaluation of student achievement in anatomy, with an enquiry into the results of cycling marking programs and confidence weighting of responses : the survey of an investigation into the results obtained over 7 years of experiment in the Department of Anatomy, University of Cape Town
    (1977) Fredman, Marcus
    The experiment of using multiple-choice tests in the Department of Anatomy grew from two concepts that had arisen in the consideration of the role of teaching in the department. The first was the need for an instrument to measure the comparative worth of any changes that we might wish to make in the methods of teaching. It was observed by Professor Wells in discussion (Wells - 1967) that, "Any change of teaching method is accompanied by an apparent but transient beneficial effect in terms of student performance". This has been called the Hawthorn effect and has been observed by educationists, but Professor Wells went further in I inking the beneficial effect to the enthusiasm of the teachers for the new methodology being communicated to the students who in tum became motivated towards performance.
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    Ancestral variation in mid-craniofacial morphology in a South African sample
    (2018) Dinkele, Elizabeth; Friedling, L Jacqui
    Ancestry estimation is a critical component of the demographic profile compiled by forensic anthropologists when unknown skeletal remains are discovered. The mid-craniofacial region is most frequently used to estimate ancestry as this region reflects the genetic and morphological ancestry of an individual. The diverse composition of the South African population makes ancestry estimation problematic, and necessitates the development of reliable, population-specific standards. This study sought to characterise variations in mid-craniofacial shape and size between South Africans of European ancestry (EA), African ancestry (AA) and Mixed ancestry (MA). Metric, nonmetric and geometric morphometric assessments were performed on 392 crania from skeletal collections in South Africa. Variations in mid-craniofacial shape and size were assessed in the orbital, nasal, zygomatic and maxillary regions in two-and three-dimensions. Univariate and multivariate statistical analyses were employed to characterise variation and estimate ancestry in AA, MA and EA individuals. Multivariate analyses suggest that tightly integrated ancestral variations in each component of the mid-craniofacial region are associated with functional, regional and developmental proximities of these regions. Specifically, AA individuals exhibited wider and shorter midfacial regions than EA individuals, who exhibited the narrowest orbital, zygomatic and nasal breadths and the longest upper facial, orbital and nasal heights. EA individuals exhibited inferiorly-angled orbits, elongated nasal apertures and anteriorly projecting nasal bridges. Rounder nasal apertures, less anteriorly projecting nasal bridges and more anteriorly projecting maxillary regions were detected in AA individuals. MA individuals exhibited heterogeneity in terms of craniofacial shape and size, and therefore produced the lowest ancestry estimation accuracies. Overall, nasal and maxillary regions were the most ancestrally diverse regions. Antemortem maxillary tooth loss and midfacial trauma were confounding factors in ancestry estimation accuracies. The lowest ancestry estimation accuracies were yielded by two-dimensional metric (27%-60.2%) and nonmetric (57.1%-82.4%) methods. Metric and geometric morphometric assessments yielded the highest repeatability (≥ 95%) indicating that these methods may be more reliable for use in medicolegal contexts. Geometric morphometric shape assessments yielded the highest ancestry estimation accuracies (75-97.9%), suggesting the presence of three dimensional shape variations between ancestry groups. These results suggest that a continuum of ancestral variation, with large areas of overlap, exists across South African populations and emphasises the need to develop multivariate ancestry estimation standards which can estimate ancestry reliably.
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    Assessing the applicability of the Greulich and Pyle (1959) skeletal age estimation method to South African children between 0 and 13 years
    (2012) Speed, Belinda; Morris, Alan.G.
    The assessment of skeletal age (SA) in both clinical and forensic settings serves to estimate the degree of development and biological maturation of a child. This is a suitable and frequently used technique, as skeletal age is a valuable indicator which can be analysed from birth until the attainment of the fully-developed adult body form. Radiographs of the hand-wrist region are most often used to estimate skeletal age, by comparing a sample radiograph against an established standard. The most internationally accepted method for skeletal age estimation is the Atlas method of Greulich and Pyle (GP) (1959). Extensive research has been conducted regarding the flexibility and applicability of this method to other race and socio-economic groups, with most research indicating that the GP Atlas is not a suitable method for skeletal age estimation for other world populations. As little research in this regard has been done using South African samples, this project aims to determine whether the GP Atlas is still an applicable method of skeletal age estimation for South African children between the ages of 0 and 13 years. Skeletal age estimates using the GP Atlas were performed on 1356 (821 males, 535 females) pre-existing digital radiographs from Red Cross War Memorial Children's Hospital, Salt River Mortuary and Tygerberg Mortuary. The target age range for this sample was birth (0) to 13 years, in order to incorporate the appearance of the ossification centres of the hand and wrist, but exclude epiphyseal fusion in this region. Although there was a strong positive correlation between skeletal age (SA) and chronological age (CA) [Males: R = 0.96; Females: R = 0.97], there was a high degree of variation in the sample, with overestimation and underestimation of skeletal age across both sexes and all age groups. This variation increased with an increase in age. Regression analysis, using a best-fit fixed-effect model, random-intercept mixed-effect model and a random intercept-random slope mixed-effect model, attempted to account for the variation in the sample by using skeletal age as a predictor for chronological age. The random intercept-random slope mixed effect model was shown to be the most appropriate model for this sample. • vii • Variables for sex, race and socio-economic status were included in the regression analysis to determine their effect on predicted chronological age. The regression model indicated that sex (and the interaction between sex and skeletal age) influenced predicted chronological age by slightly reducing the sample variation, but the sample was too variable for the effects of race and socio-economic status to be determined. The model also indicated that the majority of the variation within the sample was due to random variation. Possible reasons for this include the differences in biological origin between the South African and GP samples, the GP methodology, and the timing of growth and development of South African children on the whole. Due to the high degree of random variation in this sample, which cannot be accounted for completely by sex, race or socio-economic status, the GP Atlas is not reliable for skeletal age estimation of South African children. Other methods, such as the Phillips (2008) method for dental maturation, should be sought as an alternative when the chronological age of a child comes into question.
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    The Bony pelvis scars of parturition and factors Influencing their manifestation
    (2012) Maass, Petra; Friedling, L J
    The aim of this study was to measure and describe the range of variation of several sites on the pelvis reported to display parturition scarring in a skeletal sample of 391 individuals (230 males and 161 females). The scar features, body and pelvic dimensions were compared according to the sex, age and time period of origin of the individuals. Correlation tests were performed to identify potential relationships between scar features, while Principal Component Analysis was used to assess the influence of body and pelvic size on scar manifestation.
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    The effects of HIV-1 infection on subcortical brain structures in children receiving ART : a structural MRI study
    (2015) Randall, Steven Ronald; Meintjes, Ernesta M; Warton, Christopher
    INTRODUCTION This project investigated volumetric differences in certain subcortical structures as measured on high-resolution structural Magnetic Resonance Imaging (MRI) scans traced manually. The sample comprised 79 5-year old children, 52 with HIV and 27 uninfected controls. Infected children were all stable on antiretroviral therapy (ART) and were from the Children with HIV early antiretroviral (CHER) cohort who have been followed since birth. The study aimed to investigate the long-term effects of HIV and ART on the developing brain. While high-resolution structural data has been analysed using automated FreeSurfer to determine volume and cortical thickness, manual tracing remains the gold standard. Thus, manual tracing was used to validate automated measures and investigate subtle group differences in selected regions of interest. METHODS Extensive clinical data were available for all participants in the study. MR images were AC-PC transformed and converted to analyse format. Structures were traced using MultiTracer software. Structures selected included the caudate, nucleus accumbens (NA), putamen (Pu), globus pallidus (GP) and corpus callosum (CC). Four of these structures occur bilaterally. Tracing was performed in 79 subjects. Three subjects were excluded due to poor quality images or pathology; 5 HIV-1 infected children were excluded as they were not randomized between treatment groups. Certain subjects were retraced for inter and intrarater reliabilities. The effect and association of ethnicity, age, birthweight and sex as possible confounders were investigated. As the groups were not well matched for ethnicity, all Cape Coloured children were excluded from further analyses. Analysis of variance was used to test the effect on structure size between HIV-1 infected children and controls, as well as between 3 treatment arms (ART deferred until clinical criteria were met, early ART for 40 weeks, early ART for 96 weeks) and uninfected controls. Analysis of covariance was used to control for the possible confounding effects of sex and age. Each structure was tested for possible association with clinical variables (CD4, CD8, CD4/CD8 ratio and CD4%) both at enrolment and time of scanning. Linear regressions were modelled using clinical variables that showed significant correlation with structure size whilst controlling for covariates. Congruence between automated FreeSurfer and manual segmentation were evaluated via Bland-Altman, Pearson r and Cronbach's alpha.
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    Facial fatness as a complicating factor in facial reconstruction
    (2015) Clarke, Carrie Anna-Marie; Friedling, Louise J; Morris, Alan G
    Although it is a reasonable assumption that a significant proportion of the variation in facial tissue thicknesses comes from anatomical differences between populations, we do not know how much of normal variation is caused by including the full range of individual obesity or slimness. Current population standard soft tissue thickness data used in facial reconstructions ignores the variation between individuals which, in theory, could be greater than the variation between populations or sexes. The aim of this study was to test if facial tissue thickness is due to the amount of sub - cutaneous fat, sex or racial origins. Methods currently used do not give a true reflection of the individual because they ignore the variation in fatness. An initial study determined if a corrective value for the non - linear distortion found between radiographic images and the physical tissues was needed. This was done by imaging cadaver heads and taking measurements from the images and the physical heads. The results demonstrated that measurements taken from LODOX® images are analogous with soft tissue measurements. Volunteers were then sought from the student body and had physical measurements and X - rays taken. The measurements allowed for both BMI and body fat percentage to be calculated. Analysis showed that body fat percentage had less of an impact than BMI, with the areas of the face most affected by change in fatness being around the chin, jaw and cheek. Analysis of the variances showed that fatness has a low impact on the soft tissues of the different ancestry groups, while having a greater impact on the soft tissues of the different sexes. The effect of changing fatness on the soft tissues is not seen in all areas of the face, but to ignore it in facial reconstruction ignores that the success of a reconstruction is not exactness but in its ability to incite recognition and lead to potential identification of the unknown target individual.
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    The foramen magnum and its contents : a magnetic resonance imaging study of the normal spatial relationships
    (1994) Lotz, Jan Willem; Els, W J
    The well-known neurological disturbances associated with caudal displacement of the cerebellar tonsils through the fora men magnum (Chiari malformation) have lead to many radiological studies of the region. With MRI, routine sagittal and parasagittal views of the craniovertebral junction have shown that the position of the cerebellar tonsils is variable, and in many otherwise healthy individuals, the inferior tonsillar margins lie within the fora men magnum itself. In some cases, this topography is associated with little signal from the surrounding cerebra-spinal fluid (CSF), indicating reduction of the cerebellomedullary cistern and, therefore, crowding of neural structures within the confines of the fora men. The objective of this study has been to examine the spatial relationship between the contents of the foramen magnum ie. the medulla and cerebellar tonsils, using a normal sample comprising 120 volunteers. Instead of the conventional measurements of distance, a ratio, the Foramen Magnum Index (FMI), has been determined, derived from the relative surface areas (pixels) of neural parenchyma and CSF, over axially and sagittaly-defined boundaries of the fora men. The FMI, with a 95th centile of 0.77, exhibits appropriate statistical correlation with tonsillar position below the level of the foramen, and is therefore considered specific. As a quantitative means of assessing the cerebellomedullary cistern, the FMI also identifies certain subjects whose tonsils are at the foramen, in whom the cistern is small with resultant neural crowding.
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    Liver anatomy, jaundice and hypertension
    (2014-12-04) Slater, Charles
    This video is intended for medical students starting off their studies in anatomy. Relevance to liver disease is emphasised.
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    Nerves in micturition
    (2014-12-04) Slater, Charles
    This video is intended for medical students starting off their anatomy and physiology studies. It is an overview of the peripheral innervation for the control of urination (micturition) and of male sexual function.
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    A statistical shape analysis of the neurocranium and long bones
    (2016) Maass, Petra; Friedling, Louise J
    Morphological variation of skeletal elements, and the potential use of such variation in distinguishing among demographic groups, is often investigated using traditional metric or non-metric assessments. Traditional approaches, however, often fail to sufficiently capture the "true" shape of features, thus also failing to identify potentially important feature characteristics. The development of geometric morphometrics has allowed more comprehensive and accurate three-dimensional data capture which maintains the geometric properties of an object while isolating the effect of size from the data. The aim of this study was to employ the geometric morphometric approach to a 3D digitized sample of 1132 South African individuals from the skeletal collections of the Universities of Cape Town, Stellenbosch, Witwatersrand and Pretoria. Morphological variation among demographic groups was assessed using Generalized Procrustes Analyses applied to the individual bones of the neurocranium and the long bones of the limbs. The ability to distinguish groups based on the detected variation was assessed using Discriminant Function Analysis. The results show that, when size is isolated from the data, only a few elements show sexual dimorphism, while all examined elements show high accuracy in distinguishing among ancestry groups (>74%). When variation is assessed using both parameters, classification accuracies of 70-83% are obtained. Comparison of the different elements shows that the best classification accuracies are based on the frontal bone (84% average) and the humerus (81% average). This study shows that the morphologies of the neurocranium and long bones vary among sex and ancestry groups. This allows assessment of how the combination of variable intrinsic and extrinsic influences can manifest on different parts of the skeleton. In a population as genetically and historically complex as that of South Africa, understanding of the impact of such influences may inform forensic assessments of skeletal material, which is especially valuable considering the high rate of violent crimes and increasing number of unidentified remains being discovered in the country.
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    Stature estimation: evaluating regression equations for different population groups in South Africa
    (2018) Arendse, Liesl Margo; Friedling, Louise J
    Stature estimations from regression formulae are used by forensic anthropologists in constructing a biological profile from unidentified human remains. Regression formulae are used to calculate total skeletal height or living stature when incomplete, fragmentary or burned human remains are recovered. This study aimed to evaluate the reliability of the total skeletal height regression formulae from (1) Lundy and Feldesman (1987), and (2) Dayal et al. (2008) when compared to total skeletal height from the full anatomical method (Fully’s method), in a contemporary South African population. The use of these regression formulae to estimate total skeletal height of South Africans of Mixed Ancestry was investigated as no population-specific standards exist for this group. Additionally, the reliability of the generic femur/stature ratio (Feldesman et al., 1990) to estimate living stature for all three population groups was investigated. Measurements were taken from 229 individuals comprising of South Africans of Mixed Ancestry, African Descent and European Descent from South African skeletal collections. ANOVA’s and paired t-tests were used to determined if there was a significant difference (p<0.05) between (1) estimated total skeletal height from regression formulae and that from Fully’s method, and (2) the estimated living stature from the femur/stature ratio and a calculated living stature from Fully’s total skeletal height with soft tissue and age correction factors. No significant difference (p>0.05) was found between South Africans of African Descent and Mixed Ancestry’s calculated total skeletal height, but both were significantly different (p<0.000) to individuals of European Descent. Results indicate that the Lundy and Feldesman (1987) regression formulae should be re-assessed for contemporary South Africans of African Descent and results from the Dayal et al. (2008) regression formulae indicate that the formulae are still relevant for contemporary South Africans of European Descent. Additionally, new regression formulae should be developed to enable forensic or physical anthropologists to estimate total skeletal height of Mixed Ancestry individuals. The femur/stature ratio’s living stature were significantly different (p<0.000) from the calculated living stature, and generally overestimated it for maximum femur lengths greater than 50cm.
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    The seminal vesicles : anatomy, comparative anatomy and development.
    (1945) Retief, Peter John Mitford
    There are many reasons which induced me to choose this subject for a thesis. I would like to mentioned only the most important one. Between 1942 and 1945, while in the South African Medical Corps, I was posted to the Wynberg Military Hospital. During this time I was closely associated with the urological service of the hospital.
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    Variations in the insertions of the tibialis posterior muscle and the structure of the medial longitudinal arch
    (2014) Sadler, Maxwell Jennings; Louw, Graham J
    This study utilized cadavers to examine the variable insertions of the tendon of tibialis posterior muscle. Both feet from 29 cadavers were dissected and six variable connections to intrinsic foot structures were documented (frequencies indicated as a per cent): sustentaculum tali (93.1%), abductor hallucis muscle (44.8%), flexor hallucis brevis muscle (22.4%), fibularis longus tendon (58.6%), plantar calcaneonavicular (spring) ligament (17.2%), and the long plantar ligament (34.5%). The frequencies for each variable insertion were also reported individually for sex and population group, as well as the most common combinations of insertions. Measurements describing the medial longitudinal arch of the feet were taken, using a soft tissue intact method (arch index) and the post-dissection method (talus-first metatarsal angle). The insertion data were then compared to the arch measurements, as well as foot side, age, sex, and population group. There was a weak negative correlation between the talus-first metatarsal angle measurement and the presence of an insertion on to sustentaculum tali, as well as a connection to the tendon of fibularis longus. Arch measurements were shown to be statistically significantly similar for left and right feet for each individual. Knowing the arch index on one side of the body allows for an accurate prediction of the arch index on the opposite side within an individual. The right arch index was larger in 55% of the sample. All other correlations were negligible, and the presence or absence of specific insertions was not an accurate predictor of either arch measure. The accumulation of multiple variable insertions did not have any impact on the arch measurements.