Evaluation of Bilateral Asymmetry in the Humerus of Human Skeletal Specimen

Abstract

Several studies have established a relationship between morphological and behavioural asymmetry making investigations of bilateral bone asymmetry an attractive and important research area. The purpose of this study was to investigate bilateral asymmetry patterns of skeletal specimen from five geographical locations (Rwanda, Burundi, Congo, Kenya and Uganda) at Galloway Osteological Collection, The angle of torsion and retroversion, mid shaft circumference, length and weight of 232 pairs of humeri were determined. A Torsiometer was used to measure the angle of torsion in degrees according to Krahl and Evans 1945, a tape was used to measure the mid shaft circumference at the level of the apex of the deltoid V and the length in cm was determined. An osteomeric board was used to measure the length of the humerus in centimeters. A weighing balance was used to measure the weight of the humerus in grams. The analysis of humeral asymmetry with respect to parameters of the human skeletal specimen at the Galloway Osteological collection Mulago revealed bilateral asymmetrical status observed in the angle of torsion, length, weight and mid-shaft circumference. Our result mostly showed lateralization to the right in all the parameters investigated except the torsion angle which is to the left. Our investigation revealed that humeral torsion is inversely proportional to weight, length and mid-shaft circumference of the humerus. This study established the existence of bilateral asymmetries in the humeri of all the geographical regions investigated with more asymmetry observed in the male compared with the female.Fong et al., 2003 study of patients with seizure disorders concluded that body asymmetries is a useful clue to diagnosis of localization related seizure and may provide clues for lateralizing seizure origin in partial onset seizures. Singh (1979) showed bilateral asymmetry in the direction and degree of tortion in metacarpal bones. According to Whiteley, (2009), "The development of humeral torsion seems to be determined by both hereditary and activity related factors (Edelson 2000;Krahl 1947) with the relative contributions of each remaining unknown. It is hypothesized that for the majority of adults, humeral torsion is largely genetic in origin, with opportunity available for activity-related influences of a less magnitude.The purpose of this study was to investigate bilateral asymmetry patterns of skeletal specimen from five geographical locations (Rwanda, Burundi, Congo, Kenya and Uganda) at Galloway Osteological Collection, . It consists of over 232 sets of skeletons both female and male and of different ages and geographical origin. It was cross-sectional descriptive and quantitative study involving measurements.