Sex determination from skull remains101

SEX DETERMINATION

1. SEX DETERMINATION FROM SKULL REMAINS
TEJASVI BHATIA

2. CONTENTS
Introduction
What is skull?
Sex determination:
by morphological characteristics
by metrical characteristics
Immature Skelton
Factors inveighing against the accuracy of sexing
Conclusion
References

3. INTRODUCTION
Sex differences have been investigated in nearly every
feature of the skull.
Assessment of sex is one of the most vital
determinations to make.
In the first place, this classification effectively cuts
the number of possible matches in half.

4. WHAT IS SKULL

5. SEX DETERMINATION
There are two methodological approaches to sexing
skeletal remains:
Metrical
Morphological

6. By metrical characteristics of skull
Many studies deal with metrical characteristics studies
in the skull.
The reliability of metrical analysis depends on the
bony features used but usually lies between 70% and
95%
Keen(1950) documented an accuracy of 85% based on
selected cranial traits & the dimensions of ‘ cape
colored’ skulls from South Africa, while
Hanihara(1959) reported 83-89% accuracy in sexing
Japanese skulls.

7. An example of a procedure may be seen for maximum
cranial length as follows:
MALE FEMALE
MEAN 186.6mm 176.6mm
S.D
6.2mm 6.9mm

8. Discriminantfunction analysis
The problem with this technique is that the standards
are temporally sensitive and population specific (both
between and within groups).
Another drawback is metrical overlap of sexes which
can be as high as 85%.
Birkby(1966) warns that discriminantfunction
measures should only be used on bones for which the
function has been developed.

9. Mastoid Process Direction
Hoshi(1962) and Demoulin(1972) invesigatedthe
mastoid region.
He specified three main directions as follows:
•M type
•N type
•F type
The conclusion of this research disagreed with
Broca’shypothesis. His own research, however, does
not provide a high level of confidence.

10. Sex determination from module
Demoulin(1972) compared mastoid height & mastoid
length with each other and with other dimensions and
used it to determine the extent of dimorphism.
Results indicated that zygomaticbreadth, mastoid
length, breadth of zygomaticprocess & mastoid
height (in that order) were the most dimorphic.

11. Another study concerns the possibility of sexual
difference in the size of the foramen magnum.
Size of Foramen Magnum

12. MandibularMeasurements
Mandibularmeasurements
can determine sex with
accuracy of 87%.
When mandibular
measurements are
combined with those of
cranium, the accuracy of
prediction improved
another 3 percent.

13. Radiographic Study
In 1958, Ceballos& Rentschlerpublished the results
of a radiographic study of sex determination of skulls
based on their interpretation of postero-anterior x-ray
head films.
With this sex of adults can be determined with an
accuracy of 88%.

14. By morphological characteristics of skull
TRAIT MALE FEMALE
Generalsize Large Small
Architecture Rugged Smooth
Supraorbitalridges Moderateto excessive “Trace” or “Slight”
Mastoidprocesses Medium to large Smallto medium
Occipitalprotuberance Large & prominent Relatively smooth
Nuchallines More evident Less evident
Occipital condyles Large Small
Frontaleminences Small Large
Parietaleminences Small Large
Orbits Square with round
margins
Round with sharp
margins
Forhead Sloping-less rounded Vertical

15. TRAIT MALE FEMALE
Palate Large, broad, U-shaped Small, parabolic
Mandible Large, broadramus, high
symphysis
Small, smallerramus,
lower sympysis
Mandibularramus
flexure
Ramusflexure Straight ramus
Chin shape U-shaped V-shaped
Gonialangle Angled Vertical
Gonialflare Pronounced Slight
Malars Higher & stout Lower, less massive,more
delicate
Teeth Large, lower molar, more
often 5 cusped
Small molars, often 4
cusped.
Cheek bones Heavier Light

17. IMMATURE SKELTON
Because sex differences in immature skeltonare not
readily observable before puberty, few attempts have
been made to look for dimorphic indicators.
Some mandible have gradually curved or rounded
borders-these turned out to be female. Male mandible
extend abruptly downward coming to a point pr
squaring off at the symphysis.
Mandibularcorpus(body) shape is another important
feature.

18. FACTORS INVEIGHING AGAINST ACCURACY
OF SEXING FROM SKULL
The three factors which inveigh against high degree of
accuracy in sexing of unknown material are:
The often fragmentary & isolated nature of the
remains available for study.
The evident age (at time of death) of the remains.
Intrinsic variability and absence of any real standards.

19. CONCLUSION
Sexing from skull insofar is a age related
phenomenon, appearing or becoming more
pronounced at puberty, and many are affected by
changes of senility, the description of sex differences
must be limited to the ages of approximately 20-55
years.

20. REFERENCES
Krogman, W.M. & Iscan, M.Y. (1986): The Human
Skelton in Forensic Science, Springfield: Thomas, C.C,
pp.
Ranson& Clement (1998): Craniofacial identification
in forensic medicine, Published by Arnold, Co-
published in US by Oxford University Press. Inc., pp.
53-59.
Stimson & C.A. Mertz (1997): Forensic Densitry, CRC
Press, pp.10

21. REFERENCES
Gaur, J.R. & Bhall, V. (2008): Forensic Anthropology in
Crime Investigation & Administration Justice, Shiv
Shakti Book Traders, pp.24-25.

22. REFERENCES
img65.imageshack.us/.../skullfrontalis8ss.jpg
www.talkorigins.org/faqs/homs/15000_side.jpg
embryology.med.unsw.edu.au/.../head/mandible.jpg
https:/.../media/efossils/jpeg/000487479.jpg
www.daviddarling.info/images/foramen_magnum.gif
www.dipaola.org/stanford/facial/facetypes/f08.jpg

23. Thank You