Significance of Sacral Index in Estimation of Sex of Sacrum Inhadoti Rajasthan

William F Masih¹, Ashok Pratap Singh² and Kunj Bihari Rathore³*

¹Professor, Department of Anatomy, Govt. Medical College Kota, Rajasthan, India
²Professor, Department of Anatomy, SSR medical college Mauritious, Rajasthan, India
³Senior Demonstrator, Department of Anatomy, Govt. Medical College Kota, Rajasthan, India

*Corresponding Author: Kunj Bihari Rathore, Department of Anatomy, Govt. Medical College Kota, Rangbari Yojna Kota, Rajasthan, India.

Received: July 01, 2017; Published: September 20, 2017

Citation: Kunj Bihari Rathore,.et al. “Significance of Sacral Index in Estimation of Sex of Sacrum Inhadoti Rajasthan”. Acta Scientific Dental Sciences 1.4 (2017).

Abstract

Introduction: Anatomists, anthropologists and forensic experts judge the sex of the skeletal material by non-metric observations. Sex-dependent differences have been noted in the pelvic bone anatomy, and so differences exist in male and female sacrum. Over the years different authors had carried various types of measurements on human sacra of different races. The well-known method for determination sex of the individual has always ideally been the Sacral Index, method as explained in the Hrdlicka’s Practical Anthropometry. The formula for Sacral Index is: Sacral Index = Width of Sacrum x 100 / Length of Sacrum.

Aims: The aim of this study was to collect data regarding morphometric measurements of maximum length and breadth of sacrum and to find out possible variations of sacral index in different individuals in relation to sex.

Material and Methods: A Cross-sectional, analytical type of study was conducted in the department of Anatomy, Govt. medical college Kota on 75 (seventy-five) adult human dry sacra of unknown sex. The sacral bones were distributed into male and female groups by discriminant functional analysis. The study sample was studied morphologically for sacral length and sacral breadth with digital sliding Vernier caliper.

Results: The men sacral index in male and female were 97.88 ± 6.16 % and 112.69 ± 10.17 % respectively. Female has the greater sacral index than male (P < 0.001).

Conclusion:The bones of the body are the last to pass away after death, next to enamel of teeth. Medico legal experts, anatomists and anthropologists use the skeletal materials for giving their opinion in respect to sex, age and stature for establishing the personal identity. Sacral index method is relevant and significant for determination of sex.

Keywords: Discriminant function analysis; Gender; Sacral index; Sex determination; sacrum

Introduction

  Establishing the identity of the human remains is one of the most important and challenging. Forensic expert and anatomist have to give their opinion for the unknown and mutilated dead body. It was by Taylor in his Book of medical jurisprudence, that the accuracy of estimating the sex from skeletal remains depends upon number of bones available [1]. That is Skull and Femur 97.35%, Coccyx and Sacrum 97.18 %, Pelvis 95 %, Skull alone 91.38 %, Femur 39.84 %, Atlas vertebra 31.18%. The high accuracy of sex assessment (88.3 %) by the discriminant analysis of the sacral base is a valid method of estimating the sex of skeletal remains from a range of populations. The sacrum is a large, triangular irregular type of bone, situated in the lower part of the vertebral column, where it is inserted like a wedge between the two hip bones [2]. Sacrum meaning ‘Temple’ in Greek and ‘Sacred’ in Latin is a large vertebral bone housing all the caudal spinal nerves [3]. The geometry of sacral length and breadth also varies among different populations leading to variations in average sacral index [1,4]. Anatomists, anthropologists and forensic experts judge the sex of the skeletal material by non-metric observations. Sexual divergence has been based upon actual measurements in different bones. There is paucity of metrical data available for sacral bone [1,5]. Sex differences exist in the male and female sacrum [6]. The sacrum can be used for sexual dimorphism as in anthropological work. The well-known method for determination sex of sacrum has always ideally been the Sacral Index method as explained in the Hrdlicka’s Practical Anthropometry [7,8].

  The formula of Sacral Index is:
Sacral Index = Width of Sacrum X 100 / Length of Sacrum.

Materials and Methods

  Sacral index was measured by taking the breadth and length of individual sacrum with the help of Vernier Digital Caliper and adopting the method as demonstrated in Hrdlicka’s Practical Anthropometry [7,8]. The stem of caliper was applied to upper surface of the body of first sacral vertebra and measurement of maximum breadth was taken across the greatest expanse of lateral masses of the bone as shown (Figure 1, 2 and 3).

Figure 1: Digital Vernier Caliper.

Figure 2: Measurement of sacral Length with digital vernier caliper.

Figure 3: Measurement of sacral Length with digital vernier caliper

  A total of 75 (seventy-five) dried completely ossified, grossly normal adult human sacra of unknown sex were assessed. The sacra were collected from Department of Anatomy of Govt. Medical College Kota. The study samples were distributed in male and female sex groups by discriminant function analysis. With the help of digital Vernier calipers different measurements were recorded in millimetres. Measurement of maximum length of sacrum was recorded by the distance from antero-superior margin of promontory to the middle of antero-inferior margin of the last sacral vertebra. Maximum breadth of sacrum was measured by taking two points at the upper part of auricular surface anteriorly.

  The sacral index (SI)is calculated with formula:
Sacral Index= Width of Sacrum X 100/ length of Sacrum.

  Differences between length and breadth done by paired Student ‘t’ test and comparison between sex done by unpaired Student ‘t’ test.

  P-value < 0.05 was considered statistically significant.

Ethical Clearance

  This study was approved by the Ethical Review Committee of Govt. Medical College Kota

Results

   The mean length of sacrum in male and female was 107.44 ± 6.95 mm and 91.65 ± 7.03 mm respectively and the mean breadth of sacrum in male and female was 104.63 ± 6.41mm and 102.77 ± 6.57 mm respectively. Sacral index in male and female is 97.88SD ± 6.16 and 112.69SD ± 10.17%respectively.

  In case of male sacral length is greater than breadth and opposite was found in female i.e. breadth is greater than length (P < 0.001) (Table 1).

Sacrl Length in Male (Mms)	Sacral Breadth in Male (Mms)	Sacral Index in Male	Sacrl Length in Female (Mms)	Sacral Breadth in Female (Mms)	Sacral Index in Female
107.44 SD ± 6.95	104.63 SD ± 6.41	97.88 SD ± 6.16%	91.65 SD ± 7.03	102.77 SD ± 6.57%	112.69 SD ± 10.17%

Table 1: Length and breadth of sacrum in male and female.

  Differences between length and breadth done by paired Student’s ‘t’ test and comparison between sex done by unpaired Student’s ‘t’ test was significant (Table 2).

	Sacrum Length	sacrum Breadth	Mean ± SD value	Minimum-maximum	P value
Male	107.44 SD ± 6.95	104.63 SD ± 6.41	107.44 ± 6.95	87.80 - 117.38	< 0.001
Female	91.65 SD ± 7.03	102.77 SD ± 6.57%	91.65 ± 7.03	73.17 - 114.57	< 0.001

Table 2: Sex- wise Length (mm), Breadth (mm), Mean ± SD, Minimum-maximum, P value.

  Mean sacral index in male and female were 97.88 ± 6.16 % and112.69 ± 10.17% respectively. Female has the greater sacral index than male (P < 0.001).

Discussion

		Mean Male sacral length	Mean Male sacral breadth	No. of sacrum	Mean Female sacral length	Mean Female sacral breadth	Mean Sacral index male	Mean sacral index female
Davivongs (1963) [4] Australian aborigine		96.5 ± 0.88	88.1 ± 0.687	100	99.9 ± 0.5	101.2 ± 0.51	104.16 ± 8.93	115.49 ± 10.39
Flander (1978)[14]	White Americans	-	-	100	-	-	106.49 ± 10.4	108.69 ± 13.59
	Black Americans	-	-	100	-	-	106.17 ± 10.36	112.35 ± 11.03
Mishra SR et al. (2003)[1] AGRA (U.P)		107.53 ± 7.03	90.58 ± 4.42	116	105.34 ± 6.222	105.16 ± 6.322	98.21 ± 4.89	117.84 ± 7
Math SC [10] MM (2006)		117.00	104.20		86.00	106.30mm	94.24%	113.19%
Patel MM (2006) [7] (Gujrat))		-	-	64	-	-	90.5 - 106% Mean 96.25%	104.8 - 131% Mean 113.25%
Arora AK et al. (2010) [9] (Punjab))		109.74 ± 11.66	91.22 ± 6.348	40	101.44 ± 8.96	114.13 ± 9.67	93.69 ± 11.57	125.35 ± 11.47
Sachdeva K et al. (2011)[12] (Punjab)		10.41 ± 1.26	91.8 ± 0.71	50	10.31 ± 0.78	10.1 ± 0.7	100.24 ± 12.54	111.14 ± 14.6
Mazumdar S et al. (2012) [11] (Indian Bengal)		100.8 ± 11.5	87.3 ± 7.4	250	96.3 ± 7.4	95.6 ± 5.7	94.9 ± 4.8	109.8 ± 7.3
Ravichandran D (2013) [16] (Tamilnadu and Andhra)		97.8	93.7	123	90.96	92.91	96.32 ± 5.40	102.29 ± 4.0
Bindra et al. (2015)[15] Indians (Haryana region)		106.85	90.89	60	108.24	106.87	101.3	117.56
YadavN et al. (2015) [13] Indian (Maharashtra)		104.7 ± 5.94	102.93 ± 4.83	140	92.6 ± 6.1	104.77 ± 6.48	98.44 ± 4.69	113.23 ± 5.61%
PRESENT STUDY 2017 (Central Rajasthan)		107.44 SD ± 6.95	104.63 SD ± 6.41	75	97.88	102.77 SD ± 6.57%	97.88 SD ± 6.16%	112.69 SD ± 10.17%

Table 3: Comparative Study of Sacral Index by different authors in different population.

  Mishra., et al. [1] examined 116 adult human dry sacra (74 males and 42 females) of Agra region and showed that mean length was greater in male (107.53 ± 7.03 mm) than female (105.34 ± 6.222), which was similar to the present study. Math [10] described that ventral straight length in male was 117.00 mm and that for female was 86.00 mm. Mean length of male sacra was significantly higher than in female which was similar to the present study. The mean (± SD) breadth of sacrum in present study in male and female was 107.44 SD ± 6.95 mm and102.77 ± 6.57 mm respectively are similar to the findings of Arora [9]. Our reading is higher than Davivong., eet al. [4] in Australian aborigine.

  Math [10] described that width of sacrum in male was 104.20 mm and that for female 106.30 mm. He also described that sacrum with maximum length measuring above 117.00 mm is definitely a male and below 86.00 mm is definitely a female.

  Arora [9] examined sacra of Punjab region and showed that maximum breadth of male sacrum was 91.22 ± 6.348 mm and in female was 114.13 ± 9.67 mm. The mean breadth of sacrum in male in present study was similar to the values reported by Math [10] and almost equal toYadav., et al. [13] but higher than Mishra., et al. [1] Mazumdar et al. [11], Bindra., et al. [16] and Ravichander., et al. [16].

  The mean sacral index in male and female in present study are 97.88 ± 6.16 % and 112.69 ± 10.17 % respectively. Female has the greater sacral index than male and the difference was statistically highly significant (< 0.001). Our study was similar to Patel [7] who had reported the range of sacral index for males as 90.5 - 106% (Mean sacral index 96.25%) and in case of female’s sacral index 104.8 - 131% (Mean sacral index 113.25%). Sacral index according to Davivong.,et al. [4] in Australian aborigine is higher in both male and female than present study.

  Our present study is similar to Math [10], Arora.,et al. [7] Mazumdar., et al. [11] who had reported average value for sacral index in male were 94.24%and for females were 113.19% and Yadva N., et al. [13] of Maharashtra but lower than Sachdeva., et al. [12] and Bindra., et al. [15] in Haryana.

Conclusion

  Sexing of sacrum, by sacral index method is relevant and significant. The average sacral index identified in the present study would be of use to forensic experts, anthropologists and anatomists of central part of Rajasthan. We recommend future studies with larger sample size.

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