Anthropometric Study of Different Angles of Left Human Scapula in Adult Bangladeshi People

Introduction: The scapula, or shoulder blade, is a triangular bone that connects the upper limb to the trunk, articulating with the humerus at the glenoid cavity. It features three borders (superior, medial, and lateral), three angles (superior, inferior, and lateral), and significant anatomical landmarks such as the scapular spine, acromion, and coracoid processes. Aim/Objectives: This study aimed to examine the morphometry of dry, fully ossified left human scapulae and identify variations between male and female scapulae. Methods: This cross-sectional study, conducted at Dhaka Medical College from July 2022 to June 2023, analyzed 140 dry, fully ossified left human scapulae of unknown sex. Sex determination was performed using Dabbs’s multivariate linear discriminant function method. Scapulae were classified into male and female groups based on measurements of various morphometric and morphological variables, including length, width, scapular angles, and glenoid cavity features. Result: To assess morphometric parameters and anatomical variations, the study examined 140 ossified left human scapulae (66 male, 74 female). In male, the mean ± SD of superior angle was 89.22 ± 4.94 mm and it ranged from 78.16mm to 98.16 mm. In female, the mean ± SD of superior angle was 85.49 ± 9.52 mm and it ranged from 45.00 mm to 96.66 mm. The mean superior angle was found to be higher in male than female and these differences were statistically significant (p<0.01). In male, the mean ± SD of inferior angle was 51.57 ± 6.13 mm and it ranged from 41.66 mm to 68.66 mm. In female, the mean ± SD of inferior angle was 48.75 ± 5.80 mm and it ranged from 36.66 mm to 75.12 mm. The mean inferior angle was found to be higher in male than female and these differences were statistically significant (p<0.01). As p<0.05, null hypothesis (no difference in measurement of superior angle and inferior angle of scapula between male and female) was rejected and alternate hypothesis (there are differences in measurement of superior angle and inferior angle between male and female) was accepted. So, result was significant. Conclusion: This study concludes that significant sexual dimorphism exists in the scapular morphology of adult Bangladeshi individuals. Males generally have larger scapular dimensions than females, and there are notable sex-based differences in anatomical variations, such as suprascapular notch types and acromion angles.