Sacral Measurements Research Articles

Sexual dimorphism of the human fetal pelvis exists at the onset of primary ossification

Human adolescent and adult skeletons exhibit sexual dimorphism in the pelvis. However, the degree of sexual dimorphism of the human pelvis during prenatal development remains unclear. Here, we performed high-resolution magnetic resonance imaging-assisted pelvimetry on 72 human fetuses (males [M]: females [F], 34:38; 21 sites) with crown-rump lengths (CRL) of 50–225 mm (the onset of primary ossification). We used multiple regression analysis to examine sexual dimorphism with CRL as a covariate. Females exhibit significantly smaller pelvic inlet anteroposterior diameters (least squares mean, [F] 8.4 mm vs. [M] 8.8 mm, P = 0.036), larger subpubic angle ([F] 68.1° vs. [M] 64.0°, P = 0.034), and larger distance between the ischial spines relative to the transverse diameters of the greater pelvis than males. Furthermore, the sacral measurements indicate significant sex-CRL interactions. Our study suggests that sexual dimorphism of the human fetal pelvis is already apparent at the onset of primary ossification.

Significance of Different Sacral Measurements in Sex Identification and Its Correlation with Caudal Epidural Block; An Egyptian Anatomical Study

Background: Sacrum is an important bone of the human skeleton. It contributes in the formation of the pelvic girdle. It has many clinical applications. So this study was performed to demonstrate the different dimensions and measurements of the sacrum to make it easy for identifying sex and performing caudal epidural block.Material and Methods: An anatomical study on 50 adult Egyptian dry complete undamaged sacra was performed in the Human Anatomy and Embryology department, Faculty of Medicine, Zagazig University, Egypt. The parameters used in this study were the different dimensions of the sacrum including the morphology of the sacral hiatus, the extensions of the auricular surface, the sacral index and the auricular index. All the measurements were performed by using a Vernier digital caliper with accuracy of 0.1mm. The measurements were recorded and their mean and standard deviations were calculated.Results: It was found that the mean values of sacrum width and height, transverse diameter of the wing and the base of sacrum were more in males than females. While auricular surface length, sacral and auricular indices were higher in females than in males. Also the mean values of width and height of the sacral hiatus were more in males than females.Conclusions: The sacral index and the maximal sacral length and width were the most significant of all the parameters used for sex identification. Also, the determination of the anatomical variations of the sacral hiatus may be helpful in increasing the success rate of caudal epidural anaesthesia.

Estimating stature in South African populations using various measures of the sacrum

The accurate estimation of stature can meaningfully contribute to the positive identification of skeletal remains of unknown individuals. Regression equations are most commonly used to estimate stature and have been derived from numerous bones. Little is however known about stature estimation from the sacrum and therefore the aim of the current study was to evaluate whether it is possible to estimate stature from various sacral measurements in South African populations. A total of 210 sacra representing 50 black males, 51 white males, 58 black females and 51 white females were measured. These measurements included anterior sacral height, anterior sacral width, maximum transverse diameter of the base, anterior sacral height of individual sacral segments (S1, S2, S3, S4, S5) as well as combinations of anterior sacral heights of segments, (i.e. S1+S2). The correlation of these measures to stature was calculated using Pearson's correlation coefficient, followed by the calculation of linear least square and multiple regression equations for the estimation of stature. Statistical analyses indicated differences between sexes and population groups with multiple regressions being slightly more accurate than regression equations derived from single variables. Standard error of estimate values for the present study fall within the ranges stated by previous researchers, with smaller stature estimation intervals reported for black South Africans and females. This study suggests that regression equations derived from the sacrum of South Africans can be used to calculate reasonable estimates of stature, in the absence of bones that yield more accurate results.