Ej Pp on Sexing of Skeletons
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Transcript of Ej Pp on Sexing of Skeletons
Sexing of Skeletal Material
Sex Determination in Skeletal Remains
Outline• Determination of sex (cranial and postcranial
methods)
– Bioprofile: Ancestry, Sex, Age, Descriptive traits: Stature, Handedness, Cranial and post cranial indices, Non metric traits
Determination of Sex• Refers to biological sex as indicated by the X and the Y
chromosomes! • Does not refer to culturally defined gender identities!
• 50% chance of correct assessment!
• Sex should be determined before age as there are morphological changes that depend on sex!
• The techniques are based on the theories of growth and sexual dimorphism - the relative size and the distinctive physical differences between males and females.
• Overlapping features are not uncommon!
Determination of Sex
• Scoring system 1-5:
»1 = Female, »2 = Possible Female»3 = Ambiguous»4 = Possible Male,»5 = Male
• Subjective methods!• If too many ambiguous features or features lean towards both sides
equally = conclude ”sex undetermined”!
Parameters for Sex Determination• The sexual characteristics develop after puberty at different
rates for males and females
• In elderly individuals, the traits in both sexes may appear more masculine
• The Pelvic bones – The most accurate attributes for sex diagnosis– Becomes distinctive during the adolescent growth
• The Skull• Other skeletal and dental elements via metrical data
Accuracy• No method is 100% accurate, but some
of them come close.
• The Pelvis alone gives an accuracy of 95%• The skull alone 90%• The pelvis and skull together 98%• Long bones alone 80-90%• Long bones and pelvis 95%• Long bones and skull 90-95%
(Krogman & Iscan 1986)
Male
Female
Inlet
Outlet
Pelvic Cavity
Inlet
Outlet
Pelvic Cavity
The female pelvis is broad and squatter
The male pelvis is narrow and long
Subpubic Angle
Female = Large angle (>90 degrees) Male = Small angle (<90 degrees)
V-shaped, narrow and sharpU-shaped, wide and rounded
Subpubic Concavity
Female = Narrow and slightly concave Male = Broad and strait
Width of the Pubic Body
Female = Broad Male = Narrow
Ischiopubic Ramus(Medial aspect)
Female = Sharp edge Male = Broad edge
Ventral Arch
Female = Marked ventral arch Male = No marking
Obturator Foramen
Female = Triangular shape Male = Ovoid shape
Greater Sciatic Notch
Female Male
Female angle is larger and wider, more than 68º
Male angle is smaller, narrow and acute, less than 68º
The Auricular SurfaceFemale = Small and more L-shaped Male = Large and flat
Preauricular Sulcus
Female = well developed marked sulcus
Actually only present in about 25% of women
Male = small sulcus. Or more often just absent
Female Male
The preauricular sulcus is a groove frequently seen on the iliac bone, adjacent and parallel to the inferior surface of the sacroiliac joint.
Acetabulum
Female = Small-MediumFaces anterolaterally
Male = Medium-LargeFaces laterally
Sacrum
Female = Broad and short. Marked curvature at S1-2 and S3-5
Male = Narrow and large with an evenly distributed curvature.
Sacral alae are broad relative to body Sacral alae are narrow relative to body
See Bass (1995)
Sex Differences of the Cranium
• The skull is the second most useful structure for determining sex.
• Dimorphic characteristics vary between the ancestral groups!
Sex Differences of the Cranium
• The size and architecture• Frontal Bone• Supra-Orbital Ridge (Glabella)• Supra- Orbital Margin• Occipital Protuberance/Nuchal Crest • Mastoid Process • Zygomatic Arch • Mandible:
– Mental Eminence– Ascending ramus – Gonial angle
Frontal Bone
Forehead is high and rounded with juvenile gracile appearance
Forehead is low and slopes posteriorly. Loss of juvenile appearance
Supra-Orbital Ridge (Glabella)
Female Male
Female = smooth Male = Prominent
Supra-Orbital Margin
Female Male
Female = sharp margins
The overall orbital outline is rounded
Male = rounded margin
The overall orbital outline is squared
Occipital Protuberance/Nuchal Crest
Female Male
Female = No marked muscle attachments or protuberance(Not rugged)
Male = Marked muscle attachments and pronouncedprotuberance(Rugged)
Mastoid ProcessThe Sterno-cleidomastoid muscle, which holds the head up, attaches here!
Female Male
Female = Small – medium Male = Medium – Large. Drop-shaped
Zygomatic Arch
Female = Ends superior to acustic meatus.
Zygomatic process is thin.Zygomatic bone is smooth and low.
Male = Ends posterior to acustic meatus, superior to mastoid process.
Zygomatic process is thick.Zygomatic bone is smooth and low.
Mental Eminence/Protuberance
Female Male
Inferior view of mandible
Male = Large and projectingLower margin of mandible is thick
Female = small and roundedLower margin of mandible is thin
Ascending Ramus
Female = Narrow Male = Broad
Gonial Angle
Female = Angle is wide (> 120 degrees)
Male = Angle between 90-100 degrees
Slight or no angle flaring Prominent angle flaring
Discriminent Functions of the Cranium
Metrical Data Used for Sexing
Epicondyle breadth of Humerus(>61mm=M, <61mm = F)(From France 1983, cited in AFIP 2005: 40)
Range charts of male (light) and female (dark)Caucasoid Negroid
From Byers (2002:187)
Metrical Data Used for Sexing
12th Thoracic vertebraYu et al. (2008)
• Most pronounced sexual dimorphic traits evident in:
• 1. Coronal diameter of superior endplate of vertebral body
• 2. Ratio of anterior middle height of body
• 3. Length of mammilary process and pedicle
• Accuracy: up tp 90%Based on 102 Korean autopsi samples
Other Methods• Discriminate functions for sex determination using
(for example):
• The Internal Acoustic Meatus of the petrous portion– Diameter: 70% accuracy (Lynnerup et al. 2006)– Angle: 83% accuracy (Norén et al. 2005)
• DNA!
The Skeletal Report Layout• Titel Page• Abstract• Introduction• Inventory and Preservation• Analysis:
– Ancestry – Sex– Age– Descriptive traits:
• Stature• Handedness• Cranial and post cranial indeces
– Non metric traits– Pathology (incl. Trauma)
• Discussion & Conclusion• References• Appendices:
– Recording forms – Photoes– Radiographs
IntroductionCase background:
• What (e.g. single burial or part of a cemetry, mass grave)• Where (site name, parish, county)• When
– when was it excavated– When does it date (forensic or archaeological (e.g. AD 16th -17th Century)
• Who excavated it? (e.g. museum, police department, organisation etc)
Inventory and Preservation
• Fill in present bones on a skeleton drawing and substantiate by text.
• Pictures/drawings can speak a thousand words!
• Nobody wants to read a very descriptive inventory in words only!!!!
• MNI –any additional remains should be identified and data derived from these should be stated.
Preservation
Fragmented/Complete
Complete = >75% presentPartial = 50% - 75% presentPoor = 50-25% presentVery Poor = <25% present
Perimortem vs postmortem damage
• Perimortem : Occurs at or near the time of death
– Regular, linear, polished, sharp, smooth edges; Discolouration of bone. Staining from surrounding soil.
• Postmortem: Occurs after death
– Irregular, crumbly, rough white edges . No evidence of remodelling. Absence of associated fracture lines.
– E.g. Erosion, weathering, scavenging, excavation
– Describe surface structure of bone (e.g. porous, flaky)
– Density of bone –dense or fragile/light bone (age and pathology may lead to weakness of bone, but no conclusions at this stage)
– Describe the postmortem damage (where it is analtomically).
– Describe colour of bone (e.g. dark brown, light yellow)
– Brief conclusions regarding the taphonomic history of the skeleton (burial environment; Acidic/alkine soil, moisture/dryness, evidence of scavenging, weathering (bleaching etc). Usually with reference to archaeological record.
Preservation
Ancestry
Methodology:
Anthroposcopy: Cranio-facial variation and post-cranial variations
and
Osteometry: Metric observations (Cranid/Fordisc)
Results
Sex• Describe what you see
• Reference the methods you use!
• State the accuracy rate of the methods (only in forensic reports)
• Results
Age
• Describe
• Reference methods
• Discuss accuracy (forensic reports)
• Results
Descriptive Traits
• Stature (methods, bones used, results, accuracy)
• Craniometrics (e.g. Brachycrany = broad and round headed)
• Handedness
• Parity?
Non Metric Variation
Cranial
Post-cranial
Dental
And more….
• …pathologies
• Discussion of findings
• Conclusion
Literature cited
• Acharya AB and Mainali S. (2008) Sex Discrimination Potential of Buccolingual and Mesiodistal Tooth Dimensions. Journal of Forensic Science 53(4):790-792
• AFIP (Armed Forces Institute of Pathology) (2005) 18th Annual Forensic Anthropology Manual. National Museum of Health and Medicines,National Transportation Safety Board Training Academy, Ashburn, Virginia
• Black T (1978) A new method for assessing the sex of fragmentary skeletal remains femoral shaft circumference. American Journal of Physical Anthropology 25:333-339
• Byers, SN (2002) Introduction to forensic anthropology. A textbook. Allyn and Bacon, Boston.• De Vito C and Saunders SR (1990) A discriminant function analysis of deciduous teeth to determine sex. Journal
of Forensic Science 35:845-858• France D (1983) Sexual dimorphism in the human humerus. Unpublished Ph.D dissertation, University of
Colorado, Boulder.• Hunt EE and Gleser I (1955) The estimation of age and sex of pre-adolescent children from bones and teeth.
American Journal of Physical Anthropology 13:479-487• Jantz RL and Moore-Jansen PH (1988) A database for forensic anthropology: Structure, content and analysis.
University of Tennessee, Knoxville, Department of Anthropology. Report of Investigations No 47. Submitted to National Institute of Justice.
• Krogman WM and Işcan MY (1986) The human skeleton in forensic medicine. 2nd ed. Springfield IL: Charles C Thomas.
• Lynnerup N, Schulz M, Madelung A and Graw M (2006) Diameter of the human internal acoustic meatus and sex determination. International Journal of Osteoarchaeology 16:118-123.
• Norén A, Lynnerup N, Czarnetzki A and Graw M (2005) The Lateral Angle. A method for sexing using the petrous bone. American Journal of Physical Anthropology 128(3):318-323
• Schutkowski H (1993) Sex determination of infant and juvenile skeletons: I morphological features. American Journal of Physical Anthropology 90:199-206
• Stables D and Rankin J (2004). Physiology in childbearing with anatomy and related biosciences. England: Elsevier.
• Washburn SL (1948) Sex differences in the pubic bone. American Journal of Physical Anthropology 6(2):199-208
• Washburn SL (1949). Sex differences in the pubic bone of Bantu and Bushman. American Journal of Physical Anthropology 7(3):425-432
• Wilson LA, Macleod N and Humphrey LT (2008) Morphometric criteria for sexing juvenile human skeletons using the ilium. Journal of Forensic Sciences 53(2): 269-278
• Yu S-B, Lee U-Y, Kwak D-S, Ahn Y-W, Jin C-Z, Zhao J, Sui H-J and Han S-H (2008) Determination of Sex for the 12th Thoracic Vertebra by Morphometry of Three-dimentional Reconstructed Vertebral Models. Journal of Forensic Science 53(3):620-625