Determination of Sex with a Discriminant Analysis of New Pelvic Bone Measurements: Part II

Abstract

The pelves of 100 white skeletons were measured on both sides for the following: (1) length from the superiormost aspect of the public symphysis to the nearest rim of the acetabulum (PS-A), (2) length from the highest point of the public tubercle to the nearest rim of the acetabulum (PT-A), (3) acetabular diameter (AD), (4) the vertical distance from the anterior aspect of the ischial tuberosity to the farthest rim of the acetabulum (IT-A), and (5) greatest femur head diameter. From these, three indices were derived: AD/PS-A (acetabulum/pubis index), AD/PT-A (acetabular diameter/pubic tubercle-acetabular rim index), and IT-A/PS-A (ischium-acetabulum height/public symphysis-acetabular rim index). The left AD/PS-A ratio and left IT-A height proved statistically to be of greatest discriminating value. Using these two variables, a discriminant function was derived which correctly separated 98% of our sample. The acetabulum/pubis ratio alone correctly assigned 95%. With either the discriminant function analysis of two variables or the acetabulum/pubis index as a single predictor, 97% of our sample of known sex was correctly identified if all specimens that fell within a doubtful or overlapping range of values were sorted by femur head diameter.

Metric sex determination from the pelvis in modern Greeks

“…The 95% accuracy when using all measurements (dropping to 93% after cross-validation) is similar to that found, for example, by Schulter-Ellis et al [27] on an American sample (95 -98%) and Patriquin et al [11] on a South African sample (up to 91%). It seems that most of the differences in the pelves between the sexes are situated in the pubic and ischial parts.…”

“…A full set of measurements could not be obtained from each of these individuals, mostly due to the presence of dried soft tissue, but sample size for each of the measurements ranged between 72 and 94 (Table 1). Using standard anthropometric techniques [1,11,26,27], the following 17 measurements were taken:…”

Determination of Sex by Discriminant Function Analysis of Lateral Radiographic Cephalometry

“…Evaluation of morphological traits is considered more subjective and depends on the experience of the investigator. Methods 9,10,13 The metric approach of sex determination is more objective and less dependent on observer's experience. Its replicability is high and it is more amenable to statistical analysis facilitating between sample and study comparison which result in low levels of intra and interobserver error and produce fewer indeterminate cases.…”

“…The studies for sex determination are based on the dimorphism between the sexes that is present in the majority of human bones. 1,2 The determination of sex, age and race is 100% using skeleton [3][4][5][6][7] , 95% reliable when using the pelvis alone, 8,9 92% using the skull alone 10 and 98% using the pelvis and skull. 8,9 Skull is probably the second best region of the skeleton to determine the sex since skull is composed of hard tissue and is the best preserved part of skeleton after death; hence, in many cases it is the only available part for forensic examination.…”

“…1,2 The determination of sex, age and race is 100% using skeleton [3][4][5][6][7] , 95% reliable when using the pelvis alone, 8,9 92% using the skull alone 10 and 98% using the pelvis and skull. 8,9 Skull is probably the second best region of the skeleton to determine the sex since skull is composed of hard tissue and is the best preserved part of skeleton after death; hence, in many cases it is the only available part for forensic examination. [5][6][7] When skulls are placed on flat surface, the male skulls rest on the mastoid process, while female skulls rest on the occipital condyles or other portions of the skull.…”