Sex estimation using humerus volume in a Korean population with varying bone preservation

In forensic anthropology, the pelvis and skull exhibit high accuracy in sex estimation; however, other skeletal elements are necessary when these are fragmentary. We aimed to develop a novel metric approach for sex estimation using the humerus. We analyzed three-dimensional images of the right and left humeri of 600 individuals through logistic regression analysis and validation of sex estimation. Logistic regression was applied to three specific parameters: maximum length, 20% volume/maximum length of the intact humerus, and 5 cm volume/the fragmentary humerus. For the maximum length, the sex estimation accuracy was 76%(right) and 75%(left), respectively. Using the 20% volume/maximum length of the intact humerus, the accuracy in the head region was 93%(right) and 91%(left); in the mid-shaft region, it was 93%(right) and 92%(left), respectively; and in the distal region, it was 92% for both sides. The accuracy for the 5 cm volume of the fragmentary humerus in the head region was 91%(right) and 93%(left), whereas in the distal region, it was 92%(right) and 89%(left), respectively. This study demonstrates that the use of three-dimensional images of the Korean humerus provides higher accuracy and reliability in sex estimation compared to conventional two-dimensional metric methods, which offer limited information on bone measurements.