Angle of Humeral Torsion: Comparative Analysis with Length and Mid-Shaft Circumference

The humeral torsion angle is a bony twist of the head of the humerus formed between the proximal and distal articular axis of the humerus, which is essentially significant to measure as it depends on biological activity. The present study was conducted with the aim to document anthropometric variables so as to provide a frame for prosthesis design of humeral components in arthroplasty. A total of 50 dry, normal adult human humeri were obtained from the Department of Anatomy in Nobel Medical College and teaching hospital to measure the angle of torsion, length, and mid-shaft circumference of each bone. The measurement of the angle of humeral torsion was performed by the Kingsley Olmsted method, whereas length and mid-shaft were measured with measuring tape. The data analysis was done in SPSS version 17 to correlate and compare the means. The average (mean± SD) angle of torsion for 50 unpaired dry humeri of both sides was compared and found to be statistically significant (p= 0.004, Right= 66.24± 8.67°, Left= 59.56± 6.7°). Mid-shaft circumference was positively correlated with the angle of torsion and was statistically significant (p=0.012, r= 0.351). The study concludes that mid-shaft circumference was found to be more with a large angle of humeral torsion, but there was no significant correlation with the length of the humeral shaft.