This document describes a study that aimed to determine sex from skeletal remains of mandibles in a population in Maharashtra, India. The study measured 13 parameters of 103 mandibles and used multivariate discriminant function analysis (MDFA) and stepwise MDFA to identify the most discriminating parameters. Stepwise MDFA found that minimum ramus breadth and mandibular angle best distinguished sex, with an accuracy of 85.4-90.3%. The study concludes mandibles in this population exhibit sexual dimorphism and the methods can determine sex.

1. CAPT RISHI POKHREL
COL RAJAN BHATNAGAR
COL SUSHIL KUMAR

2. INTRODUCTION
 Determination of sex from skeletal remains – initial step in
determination of identity
 Human mandible - among the strongest bones
- significant sexual dimorphism
 Multivariate Discriminant Functional Analysis (MDFA)
– best among metric methods.
 Population: Marathwada region of Maharashtra.

3. AIMS & OBJECTIVES
 To test sexual dimorphism in mandibles of population under
study.
 To identify parameters of mandible that show maximum sexual
dimorphism
 To determine population specific cut off point and constants for
MDFA.
 To test the accuracy of MDFA.

4. MATERIALS & METHODS
 Cross sectional, observational study
 Adult mandibles of known sex from Anatomy department, GMC,
Aurangabad.
 Sample size : 103
 Males: 77
Female,
26
 Females : 26
Male, 7
 Exclusion criteria 7
 Incomplete
 Gross asymmetry
 Extreme of ages

7. MATERIALS USED

8. MATERIALS USED

9. PARAMETERS USED
Parameter (Midline) Abbn. Parameter (Bilateral) Abbn.
Symphyseal height ID GN Height of mandibular body HT
Bicondylar breadth CDL CDL Mandibular thickness at mental MB
foramen
Bigonial breadth GO GO Minimum ramus breadth MnRb
Mandibular length ML Maximum ramus breadth MxRB
Intermolar distance IMD Mandibular or gonial angle A
Intercanine distance ICD
Arch perimeter AP Units mm, degree, cms

13. STATISTICAL ANALYSIS
 MDFA (multivariate discriminant function analysis)
 Stepwise MDFA
 Analysis : SPSS 19

14. OBSERVATIONS
&
RESULTS

15. MEAN VALUES
140
120
MALES
100
80 FEMALES
60
40
20
0
ID GN HT LT MB LT GO GO CDL CDL Mn RB Mx RB Mx RH ML A IMD ICD AP

16. DESCRIPTIVE STATISTICS
Variable TOTAL (N = 103) MALE (N = 77) FEMALE (N = 26) P
value
MEAN SD MEAN SD MEAN SD
ID GN 27.06 4.27 27.55 4.25 25.62 4.07
0.0456
HT 26.48 3.48 26.77 3.46 25.60 3.43
0.138
MB 10.60 1.33 10.74 1.39 10.17 1.05
0.059
GO GO 100.20 9.86 101.90 8.99 95.15 10.74
0.002
CDL CDL 115.63 9.40 116.86 7.76 111.96 12.6
0.021
Mn RB 33.61 5.69 35.35 5.38 28.47 2.74
<0.001
Mx RB 43.03 6.27 44.83 5.85 37.69 4.09
<0.001
Mx RH 63.17 7.25 64.13 6.64 60.32 8.32
0.020
ML 66.62 7.00 68.22 6.31 61.89 6.91
<0.001
A 118.79 6.87 117.84 6.67 121.58 6.81
0.016
IMD 36.55 5.87 36.80 5.88 35.80 5.90
0.456
ICD 23.10 7.01 23.91 7.26 20.68 5.65
0.042
AP 7.011 1.00 7.08 1.06 6.80 0.81
0.228

17. Parameter b
STEP 1: MDFA ID GN -0.037
Multivariate discriminant function HT 0.076
f (x) = b0 + b1x1 + b2x2 + b3x3 + --------- + b13x13. MB 0.267
GO GO -0.050
Where, f (x) : MDFA score CDL CDL 0.041
b0 : constant (-7.704) Mn RB -0.185
Mx RB -0109
b1 to b1 : raw coefficients
Mx RH 0.053
x1 to x13 : variables values
ML -0.015
 f(x) at group centroid for males = - 0. 556 A 0.101
IMD 0.053
 f(x) value at group centroids for females = 1.648
ICD 0.033
 Demarcation point = 1.09
AP -0.301

18. STEP 2: STEPWISE MDFA
 A combination of MnRB and A was found to be best among all.
 The function
f (y) = b0 + b1 (MnRB) + b2 (A)
b0 = 3.755
b1 = 0.202
b2 = - 0.089
 f(x) at group centroid for males = 0.435
 f(x) value at group centroids for females = -1.288
 Demarcation point = - 0.9628

19. RESULTS
MDFA S-MDFA
100
Percentage
80
60
40
20
0
Male Female Overall
METHOD Male Female Male % Female % Overall %
MDFA 72/77 21/26 93.5 80.8 90.3
S- MDFA 76/77 12/26 98.7 46.2 85.4

20. FUNCTION FOR MDFA
 f(x) = (- 0.704) + (-0.037) ID GN + (0.076) HT + MB (0.267) +GO GO (-
0.050) + CDL CDL (0.041) + MnRB (-0.185) + MxRB( -0109) + MxRH (0.053)
+ ML (-0.015) + A (0.101) + IMD (0.053) + ICD (0.033) + AP (-0.301)
 f(x) > 1.09, the mandible belongs to female
f(x) < 1.09, the mandible belongs to male
 Accuracy : 90.3%

21. FUNCTION FOR S - MDFA
 f(y) = 3.744 + (0.202) MnRB + (-0.089) A
 If, f(y) > - 0.9628 the mandible belongs to male and if
f(y) < - 0.9628, the mandible belongs to female
 Accuracy: 85.4%

22. DISCUSSION
Author (s) with population No of Parameters Accuracy %
used
(Hanihara, 1959), Japan 4 88.6
(Giles, 1964), USA 3–8 82.0 – 88.0
(Potsch-Schneider et al., 1985), Germany 17 71.6 - 81.7
(Steyn & Iscan, 1998), South Africa 5 81.5
(Barthélémy et al., 1999), France 2-7 87.3
(Muñoz et al., 2001), Spain 1 - 14 78.3 - 88.7
(Vodanović et al., 2006), Croatia 1-9 74.12 – 92.06
(Simona et al., 2007), Romania 5-7 86.0
(Saini et al., 2011), Varanasi, India 1-5 60.3 - 80.2
Current study, 2012, Maharashtra, 2 - 13 85.4 – 90.3
India

23. Saini et al, 2011, Indian Population (Varanasi)
Sample size : Total 116, Male 92, Female 24
Functions and Variables Avg. Acc. %
Max. ramus br. + min. Ramus. br. + condylar ht. + projective ht. + 80.2
coronoid ht.
Max. ramus br. + min. ramus br. + coronoid ht. 80.2
Condylar ht + projective ht + coronoid ht. 76.7
Coronoid ht. 74.1
Condylar ht. 72.4
Projective ht. 68.1
Max ramus br. 62.1
Min ramus br. 60.3
Our study Maximum 90.3% Minimum 85.4%

24. CONCLUSIONS
 Mandibles of population under study show sexual
dimorphism.
 MnRB and A show maximum sexual dimorphism.
 Population specific coefficients, constants and
demarcation points for MDFA are derived.
Accuracy of sexing is comparable to other
populations.