Anatomy's missing faces: An assessment of representation gaps in atlas and textbook imagery.

Previous research suggests that underrepresentation in medical curricula perpetuates inequities in healthcare. This study aimed to quantify the prevalence of human phenotypic diversity (e.g., skin tone, sex, body size, and age) across 11 commonly used anatomy atlases and textbooks in pre-clerkship medical education, published from 2015 to 2020. A systematic visual content analysis was conducted on 5001 images in which at least one phenotypic attribute was quantifiable. Anatomy images most prevalently portrayed light skin tones, males, persons with intermediate body sizes, and young to middle-aged adults. Of the 3883 images in which there was a codable skin tone, 81.2% (n = 3154) depicted light, 14.3% (n = 554) depicted intermediate, and 4.5% (n = 175) depicted dark skin tones. Of the 2384 images that could be categorized into a sex binary, 38.4% (n = 915) depicted females and 61.6% (n = 1469) depicted males. A male bias persisted across all whole-body and regional-body images, including those showing sex organs or those showing characteristics commonly associated with a specific sex (e.g. for males, facial hair and/or muscle hypertrophy). Within sex-specific contexts, darker skin was underrepresented, but male depictions displayed greater overall skin tone variation. Although most images could not be assigned to a body size or age category, when codable, these images overwhelmingly depicted adults (85.0%; 482 of 567) with smaller (34.7%; 93 of 268) or intermediate (64.6%; 173 of 268) body sizes. Ultimately, these outcomes provide reference metrics for monitoring ongoing and future efforts to address representation inequalities portrayed in anatomical imagery.

Survey response rates in health sciences education research: A 10-year meta-analysis.

Growth in the online survey market may be increasing response burden and possibly jeopardizing higher response rates. This meta-analysis evaluated survey trends over one decade (2011-2020) to determine: (1) changes in survey publication rates over time, (2) changes in response rates over time, (3) typical response rates within health sciences education research, (4) the factors influencing survey completion levels, and (5) common gaps in survey methods and outcomes reporting. Study I estimated survey publication trends between 2011 and 2020 using articles published in the top three health sciences education research journals. Study II searched the anatomical sciences education literature across six databases and extracted study/survey features and survey response rates. Time plots and a proportional meta-analysis were performed. Per 2926 research articles, the annual estimated proportion of studies with survey methodologies has remained constant, with no linear trend (p > 0.050) over time (Study I). Study II reported a pooled absolute response rate of 67% (95% CI = 63.9-69.0) across 360 studies (k), totaling 115,526 distributed surveys. Despite response rate oscillations over time, no significant linear trend (p = 0.995) was detected. Neither survey length, incentives, sponsorship, nor population type affected absolute response rates (p ≥ 0.070). Only 35% (120 of 339) of studies utilizing a Likert scale reported evidence of survey validity. Survey response rates and the prevalence of studies with survey methodologies have remained stable with no linear trends over time. We recommend researchers strive for a typical absolute response rate of 67% or higher and clearly document evidence of survey validity for empirical studies.

Muscular anatomy of the forelimb of tiger (Panthera tigris).

Dissection reports of large cats (family Felidae) have been published since the late 19th century. These reports generally describe the findings in words, show drawings of the dissection, and usually include some masses of muscles, but often neglect to provide muscle maps showing the precise location of bony origins and insertions. Although these early reports can be highly useful, the absence of visual depictions of muscle attachment sites makes it difficult to compare muscle origins and insertions in living taxa and especially to reconstruct muscle attachments in fossil taxa. Recently, more muscle maps have been published in the primary literature, but those for large cats are still limited. Here, we describe the muscular anatomy of the forelimb of the tiger (Panthera tigris), and compare muscle origins, insertions, and relative muscle masses to other felids to identify differences that may reflect functional adaptations. Our results reiterate the conservative nature of felid anatomy across body sizes and behavioral categories. We find that pantherines have relatively smaller shoulder muscle masses, and relatively larger muscles of the caudal brachium, pronators, and supinators than felines. The muscular anatomy of the tiger shows several modifications that may reflect an adaptation to terrestrial locomotion and a preference for large prey. These include in general a relatively large m. supraspinatus (shoulder flexion), an expanded origin for m. triceps brachii caput longum, and relatively large m. triceps brachii caput laterale (elbow extension), as well as relatively large mm. brachioradialis, abductor digiti I longus, and abductor digiti V. Muscle groups that are well developed in scansorial taxa are not well developed in the tiger, including muscles of the cranial compartment of the brachium and antebrachium, and m. anconeus. Overall, the musculature of the tiger strongly resembles that of the lion (Panthera leo), another large-bodied terrestrial large-prey specialist.

Racism, structural racism, and the American Association for Anatomy: Initial report from a task force.

In 2021, the American Association for Anatomy (AAA) Board of Directors appointed a Task Force on Structural Racism to understand how the laws, rules, and practices in which the Association formed, developed and continues to exist affect membership and participation. This commentary is the first public report from the Task Force. We focus on African Americans with some comments on Jews and women, noting that all marginalized groups deserve study. Through much of its 130 year history, some members were an essential part of perpetuating racist ideas, the Association largely ignored racism and had some practices that prevented participation. The Task Force concluded that individual and structural racism within the AAA, combined with the broader social context in which the Association developed, contributed to the current underrepresentation of African Americans who constitute 4.1% of the membership even though 13.4% of the U.S. population is Black. Intentional efforts within the AAA to reckon with racism and other forms of bias have only begun in the last 10-20 years. These actions have led to more diverse leadership within the Association, and it is hoped that these changes will positively affect the recruitment and retention of marginalized people to science in general and anatomy in particular. The Task Force recommends that the AAA Board issue a statement of responsibility to acknowledge its history. Furthermore, the Task Force advocates that the Board commit to (a) sustaining ongoing projects to improve diversity, equity, and inclusion and (b) dedicating additional resources to facilitate novel initiatives.

Ontogenetic changes to bone microstructure in an archaeologically derived sample of human ribs.

There is considerable variation in the gross morphology and tissue properties among the bones of human infants, children, adolescents, and adults. Using 18 known-age individuals (nfemale  = 8, nmale  = 9, nunknown  = 1; birth to 21 years old), from a well-documented cemetery collection, Spitalfields Christ Church, London, UK, this study explores growth-related changes in cortical and trabecular bone microstructure. Micro-CT scans of mid-shaft middle thoracic ribs are used for quantitative analysis. Results are then compared to previously quantified conventional histomorphometry of the same sample. Total area (Tt.Ar), cortical area (Ct.Ar), cortical thickness (Ct.Th), and the major (Maj.Dm) and minor (Min.Dm) diameters of the rib demonstrate positive correlations with age. Pore density (Po.Dn) increases, but age-related changes to cortical porosity (Ct.Po) appear to be non-linear. Trabecular thickness (Tb.th) and trabecular separation (Tb.Sp) increase with age, whereas trabecular bone pattern factor (Tb.Pf), structural model index (SMI), and connectivity density (Conn.D) decrease with age. Sex-based differences were not identified for any of the variables included in this study. Some samples display clear evidence of diagenetic alteration without corresponding changes in radiopacity, which compromises the reliability of bone mineral density (BMD) data in the study of past populations. Cortical porosity data are not correlated with two-dimensional measures of osteon population density (OPD). This suggests that unfilled resorption spaces contribute more significantly to cortical porosity than do the Haversian canals of secondary osteons. Continued research using complementary imaging techniques and a wide array of histological variables will increase our understanding of age- and sex-specific ontogenetic patterns within and among human populations.

Diet and adult age-at-death among mobile foragers: A synthesis of bioarcheological methods.

OBJECTIVES: The research explores whether the combined study of cortical bone histology, bone morphology, and dietary stable isotopes can expand insights into past human health and adaptations, particularly dietary sufficiency and life span. MATERIALS AND METHODS: Midthoracic rib cortices from 54 South African Late Holocene adult skeletons (28 M, 24 F, two sex undetermined) are assessed by transmitted-light microscopy for cross-sectional area measurements, osteon area (On.Ar), osteon population density, and presence/absence of secondary osteon variants. Values for δ13 Cbone collagen , δ15 Nbone collagen , 14 C dates, Southwestern and Southern Cape geographic regions, body size measures, estimated ages-at-death from both morphological and histological methods are integrated into analyses, which include Spearman correlations, χ2 tests and Kruskal-Wallis ANOVAs. RESULTS: There is reduced On.Ar variability with higher δ15 N (r = -.41, p = .005); rib %cortical area and δ15 N are negatively correlated in the Southern Cape group (r = -.60, p = .03). Osteon variants are more common in older adults; histological ages at death are significantly older than those determined from gross morphology. DISCUSSION: We found bone tissue relationships with measures of diet composition, but indicators of dietary adequacy remain elusive. Relationships of tissue quality and isotopes suggest that some Southern Cape adults lived long lives. Osteon variants are associated with age-at-death; some association with diet remains possible. Gross morphological methods appear to underestimate adult ages-at-death, at least among small-bodied adults.

The Influence of Body Size and Bone Mass on Cortical Bone Histomorphometry in Human Ribs.

This study examines the influence of human adult body size and bone mass on cortical bone histomorphometry, and explores microstructural variation in mid-thoracic ribs. The sample consists of 213 individuals (n female = 82, n male = 131, mean age-at-death = 47.96 ± 15.71 years) from the Kirsten Skeletal Collection, Stellenbosch University, South Africa. Maximum femur length and femur maximum head diameter are used as proxies for height and weight; total cross-sectional area, endosteal area, and cortical area are used to derive measures of bone mass. Histomorphometric variables include osteon population density (OPD) and osteon area (On.Ar). Partial correlations, controlling for age, test for significant relationships among variables. A hierarchical regression model is used to determine unique variable contributions to On.Ar and OPD. Body size measurements do not correlate with either bone mass or histomorphometric variables, suggesting that size-standardization may not be necessary in studies of rib bone microstructure. Age is the most significant factor affecting OPD, while OPD is the best predictor of On.Ar. These findings suggest that age-related secondary osteon crowding affects osteon geometry. Understanding the biological mechanisms that direct bone remodeling and determine microstructural variation is essential for interpreting histological data. Anat Rec, 301:1788-1796, 2018. © 2018 Wiley Periodicals, Inc.

Sex-specific patterns in cortical and trabecular bone microstructure in the Kirsten Skeletal Collection, South Africa.

OBJECTIVES: The purpose of this study was to provide bone histomorphometric reference data for South Africans of the Western Cape who likely dealt with health issues under the apartheid regime. METHODS: The 206 adult individuals (n female = 75, n male = 131, mean = 47.9 ± 15.8 years) from the Kirsten Skeletal Collection, U. Stellenbosch, lived in the Cape Town metropole from the late 1960s to the mid-1990s. To study age-related changes in cortical and trabecular bone microstructure, photomontages of mid-thoracic rib cross-sections were quantitatively examined. Variables include relative cortical area (Rt.Ct.Ar), osteon population density (OPD), osteon area (On.Ar), bone volume fraction (BV/TV), trabecular number (Tb.N), trabecular thickness (Tb.Th), and trabecular spacing (Tb.Sp). RESULTS: All cortical variables demonstrated significant relationships with age in both sexes, with women showing stronger overall age associations. Peak bone mass was compromised in some men, possibly reflecting poor nutritional quality and/or substance abuse issues throughout adolescence and early adulthood. In women, greater predicted decrements in On.Ar and Rt.Ct.Ar suggest a structural disadvantage with age, consistent with postmenopausal bone loss. Age-related patterns in trabecular bone microarchitecture are variable and difficult to explain. Except for Tb.Th, there are no statistically significant relationships with age in women. Men demonstrate significant negative correlations between BV/TV, Tb.N, and age, and a significant positive correlation between Tb.Sp and age. CONCLUSIONS: This research highlights sex-specific differences in patterns of age-related bone loss, and provides context for discussion of contemporary South African bone health. While the study sample demonstrates indicators of poor bone quality, osteoporosis research continues to be under-prioritized in South Africa.

Cortical bone histomorphology of known-age skeletons from the Kirsten collection, Stellenbosch university, South Africa.

OBJECTIVES: Normal human bone tissue changes predictably as adults get older, but substantial variability in pattern and pace remains unexplained. Information is needed regarding the characteristics of histological variables across diverse human populations. METHODS: Undecalcified thin sections from mid-thoracic ribs of 213 skeletons (138 M, 75 F, 17-82 years, mean age 48 years), are used to explore the efficacy of an established age-at-death estimation method and methodological approach (Cho et al.: J Forensic Sci 47 (2002) 12-18) and expand on it. The ribs are an age-balanced sample taken from skeletonized cadavers collected from 1967 to 1999 in South Africa, each with recorded sex, age, cause of death and government-defined population group (129 "Colored," 49 "Black," 35 "White"). RESULTS: The Ethnicity Unknown equation performs better than those developed for European-Americans and African-Americans, in terms of accuracy and bias. A new equation based solely on the study sample does not improve accuracy. Osteon population densities (OPD) show predicted values, yet secondary osteon areas (On.Ar) are smaller than expected for non-Black subgroups. Relative cortical area (Ct.Ar/Tt.Ar) is low among non-Whites. CONCLUSIONS: Results from this highly diverse sample show that population-specific equations do not increase estimate precision. While within the published range of error for the method (±24.44 years), results demonstrate a systematic under-aging of young adults and over-aging of older adults. The regression approach is inappropriate. The field needs fresh approaches to statistical treatment and to factors behind cortical bone remodeling.