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1、法医人类学Forensic Anthropology,性 别 鉴 定 Sex Determination,IntroductionSexual dimorphismThe Immature SkeletonThe Adult Skeleton:Morphology C The skull C The pelvis C Other postcranial indicatorsThe Adult Skeleton:Metric AnalysisParturition ScarsSummary and Conclusions,Sex Determination,C,Introduction,1.As
2、sessment of sex is one of the most vital determinations to make when it is necessary to establish identity from skeletal remains.2.Unfortunately,this is often not a simple process since male and female attributes span a continuum of morphologic configurations and metric measures in the skeleton.Alth
3、ough some bones are better indicators than others,there is no skeletal feature that rivals the definitiveness of differences between fleshed individuals.3.Cross-dressers are also a problem and identification may be delayed or even impossible without a thorough skeletal examination.4.One must be part
4、icularly careful in mass disasters where both bones and personal items may be comingled.,Sexual Dimorphism,In normal,living humans,sex is a discrete trait determined by the actions of the XX or XY genotype and diagnosed by observing one of only two possible morphological features.These differences(e
5、.g.external genitalia)are apparent at birth and clearly recognizable even during the prenatal period.In the skeleton,however,the most effective sex indicators do not begin to develop until adolescence,and some are not fully expressed until adulthood.Although almost every human bone has been analyzed
6、,both metrically and morphologically,even a complete,mature pelvis cannot consistently guarantee more than 95%separation of the sexes.,There are two methodological approaches to sexing skeletal remains:morphological and osteometric.Morphologic techniques focus on shape the bony configurations that a
7、re macroscopically visible and differ between males and females.Metric analysis,based on bone dimensions,is the method of choice for skeletal parts like long bones that do not exhibit clearly definable shape variants.,Sexual Dimorphism,C,C,Basic Principles of Sexual Dimorphism,Size:males usually lar
8、gerRobusticity and muscularity usually more evident in males,The Immature Skeleton,Figure 1.Sex differences in the immature mandible.Female morphology(above)has a rounded corpus shape with a gradual transition from the lateral body to the symphysis.Males(below)show a steep abrupt transition with an
9、angular corpus(not dental arcade)shape,The Adult Skeleton:Morphology,When the morphologic expressions of sexual dimorphism in the adult skeleton are easily distinguishable they provide the most consistently reliable means of diagnosing sex.The best places to look for these formations are the skull a
10、nd pelvis.,Sex differences in the skull are mainly due to sexual dimorphism.The male is larger,more rugged,and muscle marked;whereas the female is smaller,more gracile and smooth.,Skull,Supraorbital ridge more marked in males,1.Sex EstimationSkullSupraorbital Ridge,Male skull is larger,has a more sl
11、oping forehead.,Female skull is smaller;retains frontal and parietal bossing,2.Sex EstimationSkullVault,2.Sex EstimationSkullVault,Posterior end of zygomatic arch extends as supramastoid crest farther in males,2.Sex EstimationSkullVault,Mastoid process is larger and more blunt in males,smaller in fe
12、males.,2.Sex EstimationSkullVault,Inion may be more prominent in males,sometimes to point of appearing hook-shaped,2.Sex EstimationSkullVault,Zygomatic arch wider in males,narrower in females,The skull,Figure 3 Sex differences in the skull(A)Male features;(B)female features;(C)morphologic gradations
13、.,3.Sex Estimation Skull Mandible,Chin more square in males,rounded in females;teeth larger in males,Figure 2 Sex difference in the adult mandible.The posterior ramus of adult males(left)is flexed at the level of the occlusal surface of the molars.The female ramus maintains the straight juvenile sha
14、pe(top right)or may flex above the occlusal level near the neck of the condyle(lower right).,3.Sex Estimation Skull Mandible,下颌骨的性别鉴定,PelvisThe best area to determine sex from the human skeleton is the pelvis,The pelvis,Figure 4 Sex differences in the pelvis Male above,female below,See also P30 of t
15、he textbook,which pelvis is mans?,WHY?,骨盆的性别鉴定,Parturition Scars,In the last 30 years,there has been considerable debate as to whether one can determine if pregnancy and parturition leave traces in the skeleton.The initial hypothesis was that these processes can tear the ligaments of the pubic bones
16、 and sacroiliac joint and are responsible for causing scars or pits at these sites.These manifestations are found on the dorsal surface of the pubis It was also claimed that the number of births can be estimated by the size and number of so-called parturition pits.However,more recent studies using b
17、ones from females of known parity disagreed with this hypothesis.The scars were found in many females who had never had children,and scar size and shape showed variation;these,too,were not related to the number of children borne by the woman.Obviously,other factors must cause similar scarring.These may include horseback riding,habitual squatting,and exercise involving hopping and jumping.,This is end of Sex Determination of forensic anthropology,
