South African Population Groups Research Articles

Prevalence of occipitalisation in a South African Black population: An original study of 1119 skulls with a review of the literature

BackgroundOccipitalisation is the most prevalent congenital abnormality at the craniovertebral junction; however, it is rare in the general population. There is a paucity of literature on osteological prevalence studies within the South African Black and broader African populations. This study aimed to establish baseline data for the prevalence of occipitalisation in the South African Black population group. MethodsOne thousand two hundred thirteen skulls from a South African Black population were initially sampled, and after exclusion criteria were applied, the sample was reduced to 1119 skulls (male 766; female 353). A morphological description of the skulls that exhibited occipitalisation was included in this study. ResultsOccipitalisation was observed in three skulls (3/1119; 0.27 %); two of the skulls were female (2/353; 0.57 %), and one was male (1/766; 0.13 %). The three occipitalised skulls exhibited fusion in three areas of the atlas: the anterior arch, lateral masses, and transverse processes. No skulls exhibited posterior arch fusion of the atlas. ConclusionThis study established a baseline prevalence of occipitalisation in the South African Black population at 0.27 % and found no significant association between sex and occipitalisation (p = 0.236). This study highlights the need for further studies in the other African population affinity groups.

Morphology and morphometry of the patella in a select Black South African sample

BackgroundFor many years, sex determination has been achieved through analysis of skeletal remains in forensic medicine. The patella can be utilized for sex determination in the absence (or damage) of the cranium, upper and lower limbs, and pelvic bones. Additionally, understanding the patella's morphology and morphometry is essential for diagnosing and treating injuries and disorders of the knee joint, as well as knee arthroplasty and patella ligament grafting (Medeiros et al., 2001). This study reviewed the morphology and morphometry of the patella in a Black African population of KwaZulu-Natal and determined if a correlation between the parameters of the patellae and sex exists. Materials and methods154 dry patellae belonging to a South African black population group were utilized to review their morphology and morphometry. The classifications of Wiberg (1941) and Borges et al. (2016) were adapted for the morphology. The seven morphometric measurements were adapted from Dayal and Bidmos (2005) and Borges et al. (2016). A p-value less than 0.05 was considered statistically significant. ResultsAccording to the Wiberg classification: Type 1 patellae were least prevalent (1.9 %), while Type 2 were most common with an incidence of 59.7 %. No statistical difference was recorded with sex (p-value = 0.517). According to Borges et al. (2016) classification: Type 1 (triangular-shaped) patellae were most prevalent in males and females (72.7 %) and Type 3 (irregular shape) patellae were least common in this study. A statistically significant difference between Borges et al. (2016) classification scheme (shape of the patella) and sexes was recorded (p-value = 0.003). A statistically significant relationship between morphometric parameters of the patella and sex was also recorded (p-value <0.001). Patella measurements were greater in males than in females. ConclusionIn this study, the patella displayed sexually dimorphic morphological and morphometric characteristics, which indicated that the patella may be used for sex determination in forensic cases with the KwaZulu-Natal population of South Africa, in addition to clinical applications such as knee arthroplasty, patellar ligament grafting, prosthesis synthesis, and patellar implants.

Increased prevalence of valgus constitutional alignment subtypes in a South African arthritic population group using the coronal plane alignment of the knee (CPAK) classification

BackgroundKnee alignment philosophies and patient specific models to improve patient reported outcomes are gaining increasing attention. The coronal plane alignment of the knee (CPAK) classification describes nine knee phenotypes and then proposes surgical alignment strategies to achieve constitutional alignment. The CPAK classification has been validated in Australian, European, Asian and North American population groups. To date no African data has been analyzed using CPAK. MethodsA total of 344 arthritic patients (608 knees) with appropriate long leg radiographs were classified based on the CPAK type. Measurements included mechanical hip-knee-angle(mHKA), medial proximal tibial angle (mMPTA) and lateral distal femoral angle (mLDFA) and the derived calculations of joint line obliquity (JLO) and arithmetic hip-knee-angle (aHKA). ResultsThe sample population was 77.9% (n = 268) female with a mean age of 68.4 ± 9.2 years. The most common CPAK types in order were type 3 (n = 174; 28.6%), type 2 (n = 155; 25.5%), type 1 (n = 94; 15.5%) and type 6 (n = 80; 13.2%). The most common limb alignment types were valgus (CPAK types 3,6,9; 41.8%). ConclusionThis study, which investigated arthritic patients from a single institution in South Africa, shows a divergence of CPAK phenotypic knee patterns relative to other international studies, with much higher proportions of valgus phenotypes (3 and 6). This regional difference should be further investigated in other South African and African population samples and used to adapt the surgical strategies employed by local surgeons.

Variations in pelvic floor thickness in relation to bony dimensions in South African women: using computed tomography scans

Pelvic floor disorders (PFDs) are a common reason for urogynaecological consultation around the world, especially in elderly women. These disorders have been associated with disruption to the structural integrity of the pelvic floor. This study explored whether there are variations in pelvic floor muscle (PFM) thickness in relation to parity, population group and age. Additionally, the study explored whether there were any correlations between PFM thickness and the bony pelvic parameters measured. This was a quantitative retrospective analysis of computerised tomography (CT) scans. A total of 125 CT scans of women belonging to black and white South African population groups were sampled from a tertiary hospital in Pretoria, South Africa. Statistical analyses were performed using Paleontological Statistics (PAST). A thicker pelvic floor was noted in black compared to white women. Pelvic floor thickness decreased with parity and age in both population groups. The intertuberous diameter, as well as the surface areas of the urogenital triangle and the perineum, were statistically significantly larger in white than in black women. Correlations between PFM thickness and bony dimensions were statistically significant for anteroposterior (AP) pelvic outlet diameter, where a greater AP outlet was associated with thinner PFMs in black women. Bony correlations with parity showed that the interspinous diameter in black women increased significantly with parity. The variations in bony pelvic dimensions and pelvic floor muscle thicknesses noted between population groups, in addition to the co-factors of parity and aging, will contribute to a better understanding of the anatomical reasons for incontinence.

Prevalence of sacral spina bifida occulta with lumbosacral transitional vertebra in a skeletal collection of a South African population

In this study, complete Sacral Spina Bifida Occulta (SSBO) and Lumbosacral Transitional Vertebrae (LSTV) with their various subtypes based on the Castellvi classification were appraised in a South African population sample. Adult human skeletons representing the three largest South African population groups, namely South African African, South African of Mixed Ancestry; South African of European descent; both biological sexes; and age range between 21 and 90 years at death were evaluated for both spinal anomalies.The number of preselected skeletons (n = 1798) from the largest collection in Africa of modern human skeletons (N = 2630) provided a strong representative South African sample. The observational study looked at lumbar and sacral vertebrae in each skeleton and any anomalous features were captured in an Excel spreadsheet.Complete SSBO with no LSTV was observed in eight subjects (8/1798; 0.44 %), while incomplete SSBO was observed in one subject (1/1798; 0.06 %), and one individual (1/1798; 0.06 %) exhibiting complete SSBO with LSTV (Type IIIB, Castellvi classification). No significant differences were observed when comparing the prevalence of the LSTV with SSBO in the male and female groups of the different population affinity groups. The number of individuals with SSBO was found in more South African Africans than in the other population groups with no significant difference between groups.This research revealed the simultaneous presence of two morphological anomalies (SSBO and LSTV) at the same vertebral segment that could result in low back pain. Variant morphology awareness is crucial for clinicians across all modalities to prevent misdiagnosis, leading to better treatment plans, and avoiding injury.

Exploring the morphological and morphometric characteristics of the mandibular lingula in dry mandibles of South African population

BackgroundThe lingula of the mandible is a small tongue-shaped bony prominence that partially overlaps the mandibular foramen. It has variable shapes among different populations which impacts its significance as a bony landmark in maxillofacial and oral surgeries. This study aimed to explore the morphological and morphometric characteristics of the mandibular lingula in dry mandibles of a South African population, to provide more knowledge on its structural variations, and location for surgeons involved with maxillofacial and oral surgeries. MethodologyThe study utilized 45 (n = 90 sides) dry human mandibles. The shapes were classified into five types, as per the classification scheme proposed by Tuli et al. (2000) and Varma and Sameer (2013). Three morphometric parameters were utilized to determine the location of the lingula. A p-value of <0.05 was considered statistically significant. ResultsThe most common type of the lingula was the truncated type 36/90 (40%), followed by the triangular type 23/90 (25.56%) and, nodular type 22/90 (24.44%). The mean height (mean ± SD) of the lingula was 7.57 ± 1.56 mm. The mean distance from the lingula to the anterior border of the mandibular ramus was 20.05 ± 3.25 mm while the mean distance from the lingula tip to the posterior border of the ramus of the mandible was 16.58 ± 2.26 mm. The mean distance was 15.81 ± 2.15 mm from the lingula to the mandibular notch. ConclusionThe present study contributes to the existing body of knowledge on the structural variation of the lingula which is important for precise location of the mandibular foramen and related structures, especially when performing any maxillofacial surgical procedures within a South African population group.

Intracranial meningiomas at a tertiary hospital: Spectrum of MRI findings with histopathologic correlation.

Intracranial meningiomas consist of a heterogenous group of histological subtypes, some of which are rare. Data that may play an important role in neurosurgical decision-making regarding the incidence and MRI features of these histological subtypes in the South African population groups, are lacking. This study aimed to assess the spectrum of MRI findings and histological subtypes of meningiomas in the South African context, with the goal of improving the paucity of literature on the topic. A retrospective review of the MRI features of 41 cases of histologically confirmed intracranial meningiomas was performed at a tertiary hospital level. Imaging features were audited and correlated with histological subtypes during statistical analysis. Eleven different histological subtypes of meningioma were encountered. World Health Organization (WHO) Grade I meningothelial meningiomas were the most common histological subgroup. Overall, meningiomas were found to be predominantly isointense to grey matter on T1-weighted imaging, irrespective of the histological subtype, with greater signal variability on T2-weighted imaging. Morphologies of specific subtypes are in keeping with the literature. Analysis of this series of intracranial meningiomas did not demonstrate statistically significant differences in MRI features between histological subtypes to allow for accurate preoperative prediction of meningioma subtype or WHO grade. This highlights the importance of definitive histopathological diagnosis rather than over-reliance on presumed benign imaging features. This original research article discusses the impact of histological subtype on the MRI appearance of intracranial meningiomas, with the aim to improve the paucity of literature on the subject in the context of the South African population.

Genetic Factors Contributing to the Pathogenesis of Essential Hypertension in Two African Populations.

The African continent has the highest prevalence of hypertension globally, with South Africa reporting the highest prevalence in Southern Africa. While the influence of genetic variability in the pathogenesis of hypertension is well described internationally, limited reports are available for African populations. This study aimed to assess the association of genetic variants and essential hypertension in a cohort of two ethnic South African population groups. Two hundred and seventy-seven hypertensive and one hundred and seventy-six normotensive individuals were genotyped for 78 variants. Genotyping was performed using the Illumina GoldenGate Assay and allele-specific polymerase chain reaction. The association of variants was assessed using the Fisher Exact test under the additive and allelic genetic models, while multivariate logistic regression was used to predict the development of hypertension. Five variants (CYP11B2 rs179998, AGT rs5051 and rs699, AGTR1 rs5186, and ACE rs4646994) were significantly associated with essential hypertension in the cohort under study. Furthermore, AGTR1 rs5186 and AGT rs699 were identified as risk factors for the development of hypertension in both ethnic groups. In two ethnic South African populations, an association was observed between renin-angiotensin-aldosterone system (RAAS)-related genes and the development of hypertension.

Three-dimensional volumetric analyses of temporal bone pneumatization from early childhood to early adulthood in a South African population.

A debate exists on whether the size of temporal bone pneumatization is a cause or consequence of otitis media (a global disease burden). However, a normal middle-ear mucosa is a prerequisite for normal temporal bone pneumatization. This study investigated the size of temporal bone pneumatization with age and the normal distribution of air cell volume in different stages of human growth postnatally. A three-dimensional computer-based volumetric-rendering technique was performed bilaterally on 248 head/brain and internal acoustic meatus computed tomography images of slice thickness ≤ 0.6 mm consisting of 133 males and 115 females with age range 0-35 years. The average volume of infant (0-2 years) pneumatization was 1920 mm3 with an expected rapid increase to about 4510 mm3 in childhood (6-9 years). The result also showed a significant increase (p < 0.001) in the volume of air cells up to the young adult stage I (19-25 years), followed by a significant decline in young adult stage II (26-35 years). However, the females were observed to experience an earlier increase than males. Also, population differences were observed as the Black South African population group showed a higher increase in volume with age than the White and Indian South African population groups, though the volumes of the latter increased up to young adult stage II. This study concludes that the pneumatization of a healthy temporal bone is expected to continue a linear increase up until at least adult stage I. Termination of temporal bone pneumatization in an individual before this stage could signify pathologic involvement of the middle ear during childhood.

Cranial measurements obtained by three-dimensional computed tomography technique in the estimation of sex of contemporary Black South Africans

Human identification forms an integral part of forensic and biological anthropology. For proper identification, a biological profile made up of biodata such as age, sex, ancestry, antemortem stature, and factors of individualization, is obtained and stored for use by anthropologists. A correct sex estimation can help unravel other anthropological parameters. South Africa has a multi-dimensionally high crime rate and its largest distinct population group (Black South Africans) is most affected by such crimes. Several authors have in the past used cranial measurements to carry out sex discrimination among South Africans, such attempts have largely been done using direct assessment of post-mortem specimens and on subjects of European Descent. This study, therefore, attempted to overcome these drawbacks by using a non-invasive method, the three-dimensional computed tomography (3DCT) to obtain population-specific data from a contemporary Black South African population group. It obtained measurements from cranial CT records of 350 Black South Africans (50 % sex ratio) housed in the Radiology Department of Charlotte Maxeke Johannesburg Academic Hospital. The Xiris and IntelliSpace software were used to reconstruct the images into three-dimensional forms from which measurements were taken. Evaluation of previously derived equations using data from the current study yielded low average classification accuracies which necessitated the formulation of new equations. Discriminant function analysis yielded acceptably high average classification accuracies for sex estimation which ranged from 78.3 % to 82.9 %.

Evaluation of the Investigator® 24plex GO! kit and associated allele frequency data for four South African population groups

In this study, population data were generated from South Africans using the Investigator® 24plex GO! Kit (QIAGEN, Hilden, Germany). Participants represented the four major population groups in South Africa, with self-reported ancestral origin being African (n = 208), European (n = 213), Indian/Asian (n = 103) or Admixed (n = 209). Allele frequency data and forensic parameters were calculated for each population group using Arlequin (v.3.5.2.2) and FORSTAT (v1.0). TPOX had the lowest discrimination capacity for all population groups, except for the African population group where THO1 was the least informative. SE33 had the highest discrimination capacity for all population groups (>0.98), with 38 different alleles observed in the Admixed population group. Samples exhibiting novel alleles or anomalies underwent massively parallel sequencing using the ForenSeq™ DNA Signature Prep kit, which confirmed the following results: one null Y allele at Amelogenin, ten instances of TPOX tri-allelism and four novel micro-variant alleles. An additional four novel alleles in SE33 were observed but remain unconfirmed, due to SE33 not being included in the ForenSeq™ DNA Signature Prep kit. Moreover, nine individuals had an allele 8 or 9 at D1S1656, where the peaks for these alleles occur before the D1S1656 marker range on the electropherogram and showed as a peak within the DYS391 marker. Although this observation was rare overall (1.2%), these nine individuals were from three of the four population groups, which motivates for the adjustment of the Investigator® 24plex PCR chemistry to avoid allelic overlap of D1S1656 with DYS391. Overall, these findings highlight the diverse genetic makeup of the South Africa population and accentuate the importance of local population studies.

Lumbosacral transitional vertebrae of 3096 individuals: Prevalence and morphology in a South African population and its association with population affinity

PurposeThis study sought to establish the prevalence and morphological characteristics of lumbosacral transitional vertebrae (LSTV) in the South African population and its correlation with South African's population affinities. MethodsA retrospective review was performed of 3096 consecutive thoracic-abdominal-pelvic radiographs at two large public hospitals in South Africa. Categorisation of LSTV was classified according to Castellvi et al. (1984): Types II, III, and IV with unilateral (A) or bilateral (B) subtypes present. The three largest South African population groups (participant self-identified), namely Black African, Coloured and White population affinities were equally sampled, comprising 1032 radiographs for each population affinity. ResultsThe overall prevalence of LSTV was 10 % (N = 308 of 3096). Prevalence by classification/type was 67.9 %, 27.6 % and 4.5 % for II, III, and IV, respectively. The most prevalent subtype was Type IIA (41.9 %), Type IIB (26 %), Type IIIB (21.8 %), and Type IV (5.8 %), respectively. Prevalence by frequency of side was bilateral (47.7 %), left (26.6 %), right (21.1 %), while 4.5 % could not be sided (Type IV morphology). The sex distribution was 53.9 % (166/308) female and 46.1 % (142/308) male. Prevalence by population affinity was 10.5 %, 9.3 % and 9.9 % for the Black African, Coloured and White population affinities, respectively. Analyses of all groups found that the Black African and Coloured populations demonstrated two statistically significant results: greater affinity for the prevalence of sacralisation (95 % CI: 0.396–4.33, p = 0.008), and sacralisation amongst males (95 %, CI: 0.42–3.36, p = 0.010). ConclusionThis study was the first dedicated study of LSTV prevalence in a South African population. There was no significant difference in the prevalence of LSTV between the three largest population groups. Statistically, sacralisation was observed in greater proportions in the Black African and Coloured populations, particularly among males.

Lewis a-b- histo-blood group antigen phenotype is predictive of severe COVID-19 in the black South African population group.

Several risk factors have been associated with SARS-CoV-2 infections and severity of COVID-19 disease it causes. This study investigated whether variations in histo-blood group antigen (HBGA) expression can predispose individuals to SARS-CoV-2 infections and severity of the disease. Nasopharyngeal swabs, randomly selected from SARS-CoV-2 positive and SARS-CoV-2 negative individuals, were tested for Lewis and H-type 1 HBGA phenotypes by ELISA using monoclonal antibodies specific to Lewis a, Lewis b and H type 1 antigens. The most common Lewis HBGA phenotype among all study participants was Lewis a-b+ (46%), followed by Lewis a-b- (24%), Lewis a+b- and Lewis a+b+ (15% each), while 55% of the study participants were H-type 1. Although SARS-CoV-2 negative individuals had a lower likelihood of having a Lewis a-b- phenotype compared to their SARS-CoV-2 positives counterparts (OR: 0.53, 95% C.I: 0.255-1.113), it did not reach statistical significance (P=0.055). The frequency of Lewis a+b+, Lewis a+B-, Lewis a-b+, H type 1 positive and H type 1 negative were consistent between SARS-CoV-2 positive and SARS-CoV-2 negative individuals. When stratified according to severity of the disease, individuals with Lewis a+b- phenotype had a higher likelihood of developing mild COVID-19 symptoms (OR: 3.27, 95% CI; 0.9604-11.1), but was not statistically significant (P=0.055), while Lewis a-b- phenotype was predictive of severe COVID-19 symptoms (OR: 4.3, 95% CI: 1.274-14.81), P=0.016. In conclusion, individuals with Lewis a-b- phenotype were less likely to be infected by SARS-CoV-2, but when infected, they were at risk of severe COVID-19.

Thoracolumbar transitional vertebrae: Quantitative differentiation and associated numeric variation in the vertebral column using skeletal remains.

Transitional vertebrae at the thoracolumbar region are called thoracolumbar transitional vertebrae (TLTV) and retain physical features from the thoracic and lumbar regions. Since TLTV were first classified 40 years ago, there has been much discrepancy regarding its features, identification and clinical relevance. Vertebral body levels are used in the medical field as a frame of reference to locate specific organs, vessels, nerves or landmarks. Any numeric variation or deviation in the vertebral column may lead to clinical errors. Previous findings have suggested a high association between numeric variation and the presence of TLTV. Therefore, the aim of this study was to identify the types of TLTV observed and to identify any possible associated numeric variation in the vertebral column. This study also aimed to validate the established technique to quantitatively differentiate TLTVfrom T12 and L1 at the thoracolumbar junction using skeletal remains from a South African population group. Skeletal remains (n = 187) remains from the Pretoria bone collection were assessed. Measurements were taken of the angle of the superior zygapophyseal processes of the last thoracic vertebra (T12), the first lumbar (L1), and identified TLTV. The results indicate a TLTV prevalence of 35% (n = 66/187). The results show that each vertebral type (T12, L1, TLTV) fall into independent confidence intervals: T12 is 188° ± 9.22 (CI: 187° < μ < 189.6°), 110° ± 7.52 (CI: 109.2° < μ < 111.3°) in L1, and 135° ± 24.51 (CI: 130.4° < μ < 139.1°) in the TLTV. This study observed that 70% of cases with TLTV was associated with numeric variation in the spine, both homeotic and meristic and that TLTV has a 35% prevalence. The results clearly show that quantitative morphometric analysis can effectively differentiate TLTV from other vertebral types at the thoracolumbar junction in skeletal remains.

An Assessment of the Association between Helicobacter Pylori and Pancreatic Cancer in a South African Population Group

An Assessment of the Association between Helicobacter Pylori and Pancreatic Cancer in a South African Population Group

A morphometric assessment of developing permanent dentition for age and sex estimation in a select South African sample

Dentition plays a crucial role in the fields of forensic science, forensic odontology and anthropology for age and sex estimation. The aim of this study was to determine the degree of sexual dimorphism and age prediction capabilities of permanent dentition using morphometric analysis. Six hundred digital panoramic radiographs (n = 600), belonging to 300 South African Black and 300 South African Indian, aged between 5.00 and 19.99 years were retrospectively examined using a cross-sectional design. The Pearson Correlation Coefficient tests were conducted to determine if a correlation exist between age, sex and each morphometric parameter. “Stepwise Regression Analysis” and “supervised machine learning classification” with a recursive feature elimination and logistic regression were then utilized to parsimoniously prune the morphometric parameters to determine the best models for age and sex estimation, respectively. Males generally displayed larger tooth dimensions than females, with the South African Black population group having larger tooth dimensions than the South African Indian population group. The morphometric parameters of the dentitions showed little sexual dimorphism, with weak correlations less than 0.1, in this study. However, strong correlations between age and the tooth length of the second and third maxillary and mandibular molars (R2 > 0.89) were recorded for the select South African Black and Indian population groups. In conclusion, the sex estimation formulae generated in this study had low performance accuracies for both population groups. However, the age estimation formulae developed from “Stepwise Regression Analysis” in this study were reliable predictors of age, with the tooth and root lengths displaying the best models for age estimation for the South African Black and Indian sample (R2 > 0.9).

The Application of the Cameriere's Methodologies for Dental Age Estimation in a Select KwaZulu-Natal Population of South Africa.

Background: The estimation of an individual’s age is a fundamental component of forensic odontology. Literary reports found that the efficiency of Cameriere methodology for age estimation varied among many population groups. Therefore, this study aimed to determine the applicability of the Cameriere methods to a select South African population of the KwaZulu-Natal (KZN) province. Materials and Methods: This cross-sectional retrospective study was conducted on 840 digital panoramic radiographs that met the inclusion criteria. Dental maturity was determined through the morphometric analysis of the seven left permanent mandibular and maxillary teeth in accordance with Cameriere et al. (2006). Moreover, the dental age was also calculated using the South African Black Bayesian formulae of the Cameriere method by Angelakopoulos et al. (2019). The paired sample t-test or Wilcoxon’s signed rank test assessed the significant difference between the chronological age and estimated dental age for the various formulae. A p-value < 0.05 was considered to be statistically significant. Results: The Cameriere et al. (2006) Italian formula and the South African Black Bayesian formulae of the Cameriere method by Angelakopoulos et al. (2019) underestimated and overestimated age in the South African Black and Indian population groups of the KZN province, respectively. Therefore, the authors generated a novel population-specific regression formulae (including and excluding third molars) using “step-wise regression analysis” and a “best-fit model” for the South African Black and Indian population groups of KZN. Conclusion: This study recommends that the population-specific formulae generated in this study be utilized in the KZN population to improve the accuracy of dental age estimation within this region.

Applicability of the Nolla Classification Scheme within the KwaZulu-Natal population of South Africa

BackgroundDental age estimation is important in clinical practice for orthodontic treatment, forensic sciences and radiology. The Nolla (1960) classification scheme is one of the most frequently utilized estimation tools in teaching and clinical practice. However, the applicability of the Nolla (1960) classification scheme in determining age in a select KwaZulu-Natal population of South Africa is unknown. Therefore, this study aimed to determine the applicability of the Nolla Classification Scheme on a select South African sample of KwaZulu-Natal and develop a regression model to extend the Nolla (1960) maturation and age norm tables beyond 17 years. Materials and methods840 digital panoramic radiographs of individuals aged between 5 and 25 years met the inclusion criteria. The 8 maxillary and 8 mandibular teeth in the left quadrant was analysed using the Nolla (1960) Classification Scheme. The paired T-test, Wilcoxon and Polynomial Regression Analysis were performed. ResultsThe original Nolla (1960) method over-estimated age for the entire sample in this study by −0.39 and −0.57 years in females and males, respectively. While, the modified Nolla (1960), highlighted an overall under-estimation in females, but over-estimation in males aged between 18.00 and 18.99 years. ConclusionThe Nolla Classification scheme over- or under-estimated dental age with the select population group, therefore population-specific tables were developed for the South African Black and Indian population groups of KwaZulu-Natal. This may increase the accuracy of age estimation of the selected South African sample within the KwaZulu-Natal region.

Bifurcation of the sciatic nerve: A descriptive study on a South African cadaver cohort

The sciatic nerve bifurcates into the tibial and common fibular nerves in six different regions: the pelvic region, gluteal region, proximal, middle, or distal third of the posterior thigh, or in the popliteal fossa. Inadequate knowledge of sciatic nerve anatomy could lead to failed nerve blocks, and damage during intramuscular injections. Limited studies have been done on African population groups and lack a quantifiable method to classify the levels of sciatic nerve bifurcation. Thus, this descriptive cadaver study aimed to assess the bifurcation level of the sciatic nerve in a South African population group using a quantifiable method. Three hundred and thirty-eight formalin-fixed limbs from three universities were dissected between March and August 2018. Type A was classified if the sciatic nerve bifurcated within the pelvic region. A sciatic nerve bifurcation level index (SNBLI) was developed for this study to quantitatively classify the region of sciatic nerve bifurcation into types B to F. Type F bifurcation was most common (79.6%), and types B and C were not observed. In 15 (0.04%) specimens, two separate nerves entered the gluteal region and converged to form the sciatic nerve distal to the piriformis, which could bifurcate either in the distal third of the posterior thigh or popliteal fossa. This is the first study to provide information on the sciatic nerve bifurcation in a large South African cadaver cohort. Moreover, we created a quantifiable method that can be used to classify the sciatic nerve bifurcation level. This will be beneficial in ensuring accurate comparison between different population groups in future.

Accuracies of discriminant function equations for sex estimation using long bones of upper extremities.

One of the scopes of practice of forensic anthropologists is the estimation of sex from skeletal remains. As a result, population-specific discriminant function equations have been developed from measurements of various bones of the human skeletons. Steyn, Patriquin (Forensic Sci Int 191 (1-3):113, 2009) noted that the lack of skeletal collections and data from most parts of the world has made this process impractical. Previous attempts to develop global discriminant function equations from measurements of the pelvis showed that population-specific equations are not necessary as equations derived from other populations yielded high sex estimation scores when applied to a different population. However, information on the suitability and applicability of generalised equations in sex estimation using long bones is still scarce. It is, therefore, the aim of this study to assess the accuracies of population-specific discriminant function equations derived from measurements of long bones of the upper limb of South African population groups. Data analysed in the current study were obtained from Mokoena, Billings, Bidmos, Mazengenya (Forensic Sci Int 278:404, 2017) and Mokoena, Billings, Gibbon, Bidmos, Mazengenya (Science & Justice 6(59):660-666, 2019) in which a total sample of 988 bones (humeri, radii, and ulnae) of South Africans of African descent (SAAD), South Africans of European descent (SAED) and Mixed Ancestry South Africans (MASA) were measured. Stepwise and direct discriminant function analyses were performed on the pooled data. Each function was used to estimate the sex of cases in each population group separately and average accuracies calculated. Thereafter, population-specific discriminant function equations were formulated for each population group and then applied to other population groups. The average accuracies of functions for pooled data ranged between 80.7 and 86.5%. The cross-validation average accuracies remained unchanged for most functions, confirming the validity of derived functions. A drop in average accuracies (0.8-5.3%) was observed when the functions were tested on a sample of SAAD while increased average accuracy was observed for the SAED and MASA (0.5-6.9%). When population-specific functions for a particular population group were applied to other groups, a wide range of a drop in average accuracies was observed (1.3 to 22.4%). This thereby confirms that population-specific equations should not be applied to other population groups. However, discriminant function equations from the pooled data of South Africans are accurate in the estimation of sex and efforts should be made towards the development and validation of such equations from as many bones of the human skeleton.