Phenice's visual sexing technique for the os pubis: a critique

Innominate bones from 362 California Indians were sexed with Phenice's three non-metrical features of the os pubis. The frequencies of marked, intermediate, and absent cases of these three morphological features were tabulated in males and females to see if unambiguous and reliable distinctions were consistently available. The results suggest that Phenice's technique offered extremely reliable sex evaluations in this material.     

Age determination of the male os pubis

An extensive (n = 739) sample of well-documented male pubic bones was examined for age-related features. Using the traditional aging methods, Todd's system was found to over-age and both the Todd and the McKern-Stewart systems did not account for age variability seen in advanced pubic bone patterns. Based on a 5-year interobserver error study, certain categories in each system were collapsed because observers could not consistently differentiate between them by morphological pattern. The traditional and the modified versions were than analyzed using linear regression analysis. All approaches perform poorly when the entire sample is used. Truncation strategies to eliminate older individuals result in substantial improvement. The traditional Todd system and its modified form are found to be the best systems. When implementation is considered, a modified Todd six-phase system is recommended.     

Skeletal age determination based on the os pubis: A comparison of the Acsádi-Nemeskéri and Suchey-Brooks methods

After reviewing various systems of age determination based on analysis of the pubic bone, the discussion concentrates on the collection and preparation of an extensive autopsy sample (n=1225) of pubic bones from modern individuals with legal documentation of age at death (death and/or birth certificates). TheSuchey-Brooks method derived from this sample is described. TheAcsádi-Nemeskéri system is evaluated in terms of the documented collection and it is seen that their five stage method focuses only on the early and late morphological changes. The intermediate stages, in which the ventral rampart is in process of completion, are not described. Their suggested age ranges do not correspond with the documented modern sample. Based on these limitations of theAcsádi-Nemeskéri method, applications of theSuchey-Brooks system are discussed.     

Anatomical and developmental bases for the ventral arc of the human pubis

The ventral arc of the pubis is frequently used for sexing adult human hip bones. This study addresses the issues of the anatomical and developmental bases for the ventral arc. Dissection of seven adult pelves (four females and three males) demonstrates that the sexes are identical in the muscular and ligamentous attachments to this ridge of bone. The tendons of gracilis and adductor brevis, which are fused for a variable extent, arise from the ridge of bone, and the fibers of the ventral pubic ligament attach to its medial border. Lateral placement of the ventral arc is defined in terms of the minimum distance between the ridge of bone and the inferior border of the symphyseal face of the pubis. The hypothesis that lateral placement of the ventral arc is positively correlated with pubic length was tested using two random samples of adult female hip bones (N = 50 for both whites and blacks) from the Hamann-Todd collection. The correlation between these variables is significant. The results support the argument that lateral placement of the ventral arc is related to the amount of postadolescent growth occurring at the symphyseal border of the pubis. Therefore, the ventral arc should not be considered as an independent criterion from pubic length in sexing adult hip bones.     

Estimation of age from the pubic symphysis by means of multiple regression analysis.

This study has been carried out to assess the age from the pubic symphysial surface employing a multiple regression analysis and a quantification theory model I analysis. Using partial regression coefficients and/or normalized scores obtained from the analyses, ages of skeletal remains can be quantitatively estimated with a fairly high reliability. The use of this method is, however, limited to the samples between 18 and 38 years of age, because age changes in the symphysial surface show large variations after about 40 years. The reliability of this method was also examined.     

A revised method of age determination using the os pubis, with a review and tests of accuracy of other current methods of pubic symphyseal aging

All current standardized methods of age determination using the os pubis were tested by blind assessment of a skeletal sample with documented ages (from the Todd collection; N = 96). No demographic data (sex, age, race, age composition) were known to the assessors prior to completion of the test. Results showed the Todd method to be more reliable than more recent component techniques and that all systems tended to underage. Therefore, modifications were made of the Todd system to eliminate this and other deficiencies, and a second test using a new sample was conducted (N = 109). The age distribution determined by the revised Todd method did not significantly differ from the actual age distribution of the second sample. Error due to race was nonsignificant. Biological stages of pubic metamorphosis are described and possible evolutionary specializations of the hominid symphysis are discussed. Revised standards for age determination are presented.     

Asymmetry of the os pubis: Implications for the Suchey‐Brooks method

Studies of skeletal development frequently document populational incidences of bilateral asymmetry. Degenerative morphological skeletal changes, attributed to age related and irregular ossification, may also progress asymmetrically, either as the result of asymmetric biomechanical factors expressed over the lifespan, asymmetric expression of physiological processes, or progressive magnification of asymmetry acquired previously during development. This study illustrates the effects of bilateral asymmetry on age at death estimates obtained from human skeletal remains. The Suchey‐Brooks method, which uses the pubic symphyseal face for age estimation (Katz and Suchey, Am J Phys Anthropol 69 1986 427–435), was selected for the study based on its widespread use. Asymmetry in the Suchey‐Brooks symphyseal age phases was found in over 60% of a sample composed of 20th century White male individuals from 18 to 86 years of age (N = 130). However, results suggest that the presence of asymmetry does not compromise the accuracy of the Suchey‐Brooks method if the morphologically older symphyseal face of an asymmetric individual is used to estimate age at death. In addition, weak directional asymmetry and a correlation between age and asymmetry were found. This suggests that a comparison of asymmetry in this area with that in other skeletal areas, where the factors originating and influencing asymmetry are better understood, may be useful in better understanding the biological processes which underlie the age markers used in the Suchey‐Brooks method. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

Determination of sex from arm bone measurements

Discriminant function analysis has been applied to numerous dimensions of the cranial and postcranial skeleton for sex determination of U.S. blacks and whites and is extended here to five measurements of the arm and wrist. These include maximum lengths of the long arm bones in addition to two measurements that reflect wrist breadth. Our results indicate that whites are more accurately classified than blacks, but seven of the 31 possible measurement combinations common to both groups yield functions with sex prediction accuracies comparable to most, but not all, functions based on other parts of the skeleton.     

Analysis of dorsal pitting in the os publis in an extensive sample of modern American females

Pubic bones from 486 modern American females between the ages of 13 and 99 were studied in an attempt to explore the relationship between the degree of dorsal pitting and the following variables: (1) number of full term pregnancies, (2) inteval since last pregnancy, (3) age of decedent.A statistical association was found between the number of full term pregnancies and the degree of dorsal pitting. However, the correlation is not strong; 17 females reported as being nulliparous have "medium to large" dorsal changes whereas 22 females having from one to five full term pregnancies have an absence of dorsal changes. Females who had their last child 15 or more years prior to death are more apt to have "medium to large" dorsal changes than are females who have more recently given birth. This effect appears to be independent of the number of full term pregnancies, but is probably related to age. When the data are analyzed by multiple regression analaysis, it is found that age and number of pregnancies are most important in predicting the degree of pitting and the effect of the interval on pitting is not significant. Age is found to be an important variable independent of the number of full term pregnancies. In nulliparas, an absence of dorsal pitting is far more frequently found in females younger than 30 than in those over 30.     

A simple univariate technique for determining sex from fragmentary femora: its application to a Scottish short cist population

A simple univariate technique for sexing individuals represented by fragmentary skeletal remains is described. The results obtained were highly consistent (about 90%) with those obtained by conventional analysis of pelvic and cranial morphology. It is suggested that using maximum anteroposterior diameter of the femoral shaft as a sex discriminator has advantages over midshaft circumference even when intact femora are available.     

中国法医人类学三十年

法医人类学在上世纪80年代开始引起中国法医学界的重视。改革开放后, 经济发展人口流动增加, 全国范围内无名尸体案件增加, 对骨骼个体识别的需求日益迫切。为了满足案件侦察的需要, 国内学者开始引进国外的有关研究结果, 并开始使用国人的材料对中国人骨骼个体识别的方法进行了广泛深入的研究。本文对中国学者近30年来在中国人骨骼年龄、性别及身高等方面的研究进行了回顾, 对相关研究与国外情况进行了比较,对有关问题的未来研究方向进行了讨论。     

Alteration of the sex determining system resulting from structural change of the sex chromosomes in the frog Rana rugosa

Rana rugosa in Japan is divided into four geographical races on the basis of the karyotype of the sex chromosomes: one in which heteromorphic sex chromosomes occur in the female sex (ZW/ZZ-system), another in which they are present in males (XX/XY-system), and the remaining two in which no heteromorphism is seen in either sex. The last two inherit the XX/XY sex determining system. Y and Z chromosomes in the former two are of the same karyotype as the no. 7 chromosomes seen in one of the latter two, whereas X and W are caused by two inversions that occurred in the original Xs (no. 7). In this study, we first attempted to detect the structural difference between the resulting X and W by examining their chiasma formation. The chiasma distribution between X and W was closely similar to that between two Xs, suggesting that the W and X are identical in structure. Regarding the change from XX/XY- to ZW/ZZ-system, the simplest explanation is that the putative female-determining gene(s) on the W grew functionally stronger by inversions. Next, we examined the sex of triploids having two Xs and one Z. The data showed that the triploids with two original Xs and a Z were all male, whereas most of those with two resulting Xs and a Z developed into females as expected. We speculated that the female-determining gene(s) on the resulting X grew mildly stronger functionally by position effect, whereas those on the W grew much stronger for some other reason (e.g., duplication). J. Exp. Zool. 286:313-319, 2000.     

Structural parameters determining the strength of the porcine vertebral body affected by tumours

Spinal metastatic disease could lead to catastrophic consequences for the patient. However, the structural parameters that explain the weakening of vertebrae affected by tumours are not fully understood. In this study, we developed a specimen-specific finite element model to predict the strength of the porcine vertebra with simulated tumours and used it to find the structural parameters determining the strength. We validated our model with mechanical testing and then we analysed the compressive strength of intact vertebrae and seven defects with different size and shape. The results showed that the minimum bone mineral mass of the cross section and areal defect fraction were the best predictors of the normalized strength. We also found that areal parameters appeared to be better predictors than the volumetric ones. In conclusion, reduction in bone strength for vertebrae weakened by metastatic tumours is mostly associated with decrease in the mechanical properties of the cross section.     

A technique for determining the distribution of pelagic fish larvae

A technique is described for studying small scale distributional patterns of fish larvae in the pelagic region. A plankton net is mounted beneath the bows of a small boat, the contents of the net are emptied continually by a suction pump. This system has advantages over previous techniques as it allows a large number of small discrete samples to be taken over a wide area in a short space of time. Preliminary results showed the population of perch larvae in Llyn Tegid is extremely clumped and the overall abundance of the larvae decreases as samples are taken progressively further away from the south-west end of the lake.