法医人类学性别鉴定课件.ppt

1、法医人类学性 别 鉴 定 Sex Determination Introduction Sexual dimorphism The Immature Skeleton The Adult Skeleton: Morphology C The skull C The pelvis C Other postcranial indicators The Adult Skeleton: Metric Analysis Parturition Scars Summary and ConclusionsSex DeterminationC Introduction1. Assessment of sex

2、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. Although some bo

3、nes 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 particularly

4、 careful in mass disasters where both bones and personal items may be comingled.Sexual DimorphismIn 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.g. ex

5、ternal 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 analyze

6、d, 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

7、that are 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 DimorphismC C Basic Principles of Sexual Dimorphism Size: males us

8、ually larger Robusticity and muscularity usually more evident in malesThe Immature SkeletonFigure 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 tran

9、sition with an angular corpus (not dental arcade) shapeThe Adult Skeleton: MorphologyWhen 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 formation

10、s are the skull and 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 males1. Sex EstimationSkullSupraorbital RidgeMale skull is l

11、arger, has a more sloping forehead.Female skull is smaller; retains frontal and parietal bossing2. Sex EstimationSkullVault2. Sex EstimationSkullVaultPosterior end of zygomatic arch extends as supramastoid crest farther in males2. Sex EstimationSkullVaultMastoid process is larger and more blunt in m

12、ales, smaller in females.2. Sex EstimationSkullVaultInion may be more prominent in males, sometimes to point of appearing hook-shaped2. Sex EstimationSkullVaultZygomatic arch wider in males, narrower in femalesThe skullFigure 3 Sex differences in the skull (A) Male features; (B) female features; (C)

13、 morphologic gradations.部部 位位男男 性性女女 性性(1).整体整体大而重，骨壁厚，颅腔较大，颅容量约1450毫升。小而轻，骨壁薄，颅腔小，颅容量约1300毫升。(2).结构结构凹突不平，肌脊明显。较光滑，肌脊不发达。(3).乳突乳突 发达，平放时乳突尖可成为支点。不发达，平放时乳突尖不成为支点。(4).枕部枕部 肌脊与枕外隆凸明显。 肌脊与枕外隆凸不明显。(5).额部额部额鳞斜度较大，表面不圆。额鳞斜度小，较圆而丰满。(6).额结节与顶结节额结节与顶结节较小较大(7).眉间突度眉间突度 大，突出于鼻根。小，较平直。(8).鼻根点凹陷鼻根点凹陷 较深。较浅。(9).眉

14、弓眉弓中等至特明显。微显至中等。(10).眼眶眼眶 类方形，较低，相对较小，眶上缘钝。类圆形，较高，较大，眶上缘锐。(11).齿槽弓齿槽弓较大，近U形。较小而尖，抛物线形。(12).枕骨髁枕骨髁 大小(13).枕骨大孔枕骨大孔 大小(14).梨状孔形状梨状孔形状 高而窄低而圆(15).面部面部 长短(16).颧骨颧骨 高而粗壮，颧弓较粗。低而薄弱，颧弓较细。3. Sex Estimation Skull MandibleChin more square in males, rounded in females; teeth larger in malesFigure 2 Sex differe

15、nce 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 shape (top right) or may flex above the occlusal level near the neck of the condyle (lower right).3. Sex Estimation Skul

16、l Mandible部部 位位男男 性性女女 性性(1).整体整体较粗大、厚、重。较薄、弱、轻。(2).下颌体下颌体 较高、平均29mm。较低、平均26mm。(3).颏部。颏部。发达，近方形，骨较厚。较弱，圆而尖，骨较薄。(4).下颌角下颌角 较粗糙，外翻，角度较小，125度。(5).下颌支下颌支 较宽较窄(6).下颌髁突下颌髁突 肥大，壮实。较弱小。下颌骨的性别鉴定下颌骨的性别鉴定 Pelvis The best area to determine sex from the human skeleton is the pelvis The pelvisFigure 4 Sex differe

17、nces in the pelvis Male above, female belowSee also P30 of the textbookwhich pelvis is mans?WHY?部部 位位男男 性性女女 性性(1).整体整体高而狭窄，骨质重，骨面粗糙，髂翼厚。低而宽阔，骨质轻，骨面光滑，髂翼薄而透光。(2).骨盆上口骨盆上口心形，纵径横径。椭圆形，横径纵径。(3).骨盆腔骨盆腔高而窄,漏斗形。短而宽，圆柱形。(4).骨盆下口骨盆下口 狭小。宽阔。(5).骶骨骶骨窄长三角形，弯曲度大。短宽三角形，弯曲度小。(6).骶骨岬骶骨岬 显著。不显著。(7).耳状面耳状面 大而直，涉及3个骶

18、椎。小而倾斜，涉及2个骶椎。(8).髂翼髂翼 较直而高。低而外张。(9).髋臼髋臼 大，向外。小，向前外。(10).耻骨联合耻骨联合 高。低。(11).耻骨弓角耻骨弓角 约7075度，V形。约90110度，U形。(12).坐骨结节坐骨结节 不外翻，坐骨结节间距9cm。(13).闭孔闭孔 大，卵圆形。小，三角形。骨盆的性别鉴定骨盆的性别鉴定 Parturition ScarsIn the last 30 years, there has been considerable debate as to whether one can determine if pregnancy and partur

19、ition leave traces in the skeleton. The initial hypothesis was that these processes can tear the ligaments of the pubic bones 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

20、the number of births can be estimated by the size and number of so-called parturition pits. However, more recent studies using bones 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