European Journal of Cardiovascular Medicine

The distinctive morphology of the human hip bone and its clear sexual dimorphism make it of interest from anatomical, anthropological and forensic points of view.  It is acknowledged that the hip bone is by far the best non-population-specific indicator for reliable sex determination. Sexual dimorphism of the hip bone results from functional modification and evolutionary adaptation. Scientists all over the world have done a large number of studies to determine the sex from the skeleton. In general, the male pelvis is significantly heavier and thicker than that of the female.  The male pelvic bones are also adapted to fit a more massive and sturdy body architecture.  For example, the male acetabulum has been designed to fit a bigger femur.

The female hip bones are also different in traits associated with the sacroiliac joint position in the iliac bone¹.  Morphology of the pelvis is an especially diagnostic tool for sex determination since female pelvic geometry permits a greater outlet for passage of the neonate head and shoulders during birth. The distinct difference in male and female pelvis after puberty suggests that the sex hormones play their role in the development. Numerous sex determination techniques have been proposed based either on the examination of specific parts of the hip bone including the pubic bone (Phenice,1969)², sciatic notch (Kelly, 1979³, Letterman, 1941⁴), sacroiliac joint (Iscan and Derrick, 1984⁵), acetabulum (Schulter-Ellis et.al. 1983,1985⁶). Hip bone is considered the most reliable sex indicator in the human skeleton⁷. Sexual differences in adults are divisible into metrical and non-metrical features, of which the metrical values of a bone are highly accurate^8,9.  Therefore with this study, an attempt was made to calculate a cut off value for the chilotic line that will be accurate for identification of sex from a hip bone in any given population.

AIMS AND OBJECTIVES:

To assess the reliability of the chilotic line of adult hip bone with respect to the chilotic line index and find a demarking point for the chilotic index that will be accurate for the identification of sex in the human hip bone.

For the present study, a sample of 178 adult human hip bones of known sex available in the bone bank of the Department of Anatomy, Government Medical College was used. Ethical clearance was issued from the institutional ethical review committee before the initiation of the study.

Inclusion criteria:

1. Undamaged adult human hip bones.
2. Bones with complete ossification.
3. Bones with no pathological deformity.

Exclusion criteria:

1. Damaged bones
2. Bones with artefacts.
3. Bones of infants and children.
4. Bones with congenital anomalies.
5. Hip bones which are not ossified.

Sufficient care was taken to avoid manual errors. For each hip bone following parameters were measured.

1. Length of sacral part of Chilotic line e., part of chilotic line extending from the nearest point on the anterior margin of the auricular surface of ilium to the iliac crest. It is measured by marking the above fixed points with a marking pencil and running a thread along the distance. The length of the thread is then recorded on the scale in cm.
2. Length of pelvic part of Chilotic linee., part of chilotic line extending from iliopubic eminence to the nearest point on the anterior margin of the auricular surface of ilium. It is measured by marking the above fixed points with a marking pencil and running a thread along the distance. The length of the thread is then recorded on the scale in cm.
3. Chilotic line index: this index is obtained by using the formula as

Sacral part of Chilotic line X 100

Pelvic part of Chilotic line

              The results were tabulated and analysed statistically.

178 adult human hip bones of known sex available in the bone bank of the Department of Anatomy, Government Medical College were studied. 

Table 1: Statistical analysis of sacral part of the chilotic line

The mean value of the sacral part of the chilotic line in males is 6.74cm, and that of females is 6.07cm, with the value of males and females ranging between 5.4 – 7.8cm and 4.6 – 7.8cm respectively.  The standard deviation for males is 0.499 and for females is 0.736. The range of mean ± 3 S.D in males is 5.24 – 8.23 and in females is 3.86 – 8.28.

The demarking point (D.P.) for males is < 3.86 and for females is > 8.23. By using D.P. no hip bones were sexed correctly when using this parameter alone. T-test is significant as P<0.001. The sacral part of the chilotic line is a reliable parameter for the identification of the sex of adult human hip bone.

Table 2: Statistical analysis of pelvic part of the chilotic line

The mean value of the pelvic part of the chilotic line in males is 5.68cm, and that of females is 6.28cm, with the value of males and females ranging between 4.18 – 7.1cm and 4.6 – 7.8cm respectively.  The standard deviation for males is 0.661 and for females is 0.659. The range of mean ± 3 S.D in males is 3.68 – 7.68 and in females is 4.3 – 8.25.

The demarking point (D.P.) for males is < 4.3 and for females is > 7.68. With the help of D.P., the percentage of hip bones sorted by this parameter alone with 100% accuracy is 1.6% of males and 3.7% of females. T-test is significant as P<0.001. The pelvic part of the chilotic line is a reliable parameter for the identification of the sex of adult human hip bone.

Table 3: Statistical analysis of chilotic line index

The mean value of the chilotic line index in males is 120.22cm, and that of females is 97.58cm, with the value of males and females ranging between 83.07 – 151.1cm and 72.3 – 160.8cm respectively.  The standard deviation for males is 14.075 and for females is 15.525. The range of mean ± 3 S.D in males is 78 – 162.45 and in females is 51 – 144.15.

The demarking point (D.P.) for males is > 144.15 and for females is < 78. The percentage of hip bones sorted by this parameter alone with 100% accuracy is 3.22% of males and 3.30% of females. T-test is significant as P<0.001. The chilotic line index is a reliable parameter for identifying the sex of adult human hip bones.

178 adult human hip bones of known sex available in the bone bank of the Department of Anatomy, Government Medical College were studied.  In the present study, the mean value of the chilotic line index in males is 120.22, and that of females is 97.58, with the value of males and females ranging between 83.07 – 151.1 and 72.3 – 160.8 respectively. The standard deviation in males is 14.075 and in females, it is 15.525. The range of mean ± 3 S.D in males is 78-162.45 and in females, it is 51-144.15. The demarking point for males is >144.15 and for females, it is <78. The percentage of hip bones sorted by this parameter alone with 100% accuracy is 3.22% for males and 3.30% for females. T-test is highly significant P<0.001.

Table 4: Comparison of chilotic line index with previous studies

A literature review showed that not much study is available in the population in the context of the metrical data on chilotic lines (pelvic and sacral segments) and chilotic index. Therefore the present study is undertaken to define a demarcating point for the above parameter so that bone identification can be easily done even if it is available in fragments^3,9.

Anatomists and anthropologists have a great interest in the nature and degree of sexual differentiation. It is also having practical importance from an obstetric point of view. Buikstra, Ubelaker (1994)¹⁰ stated that “Estimates of sex therefore can be difficult if the observer is not familiar with the overall pattern of variability within the population from which the sample is drawn overall”. Scientists all across the world have made several attempts to identify sex from individual bones. In the first part of the study, all the values are tabulated and analysed statistically by routine methods. The values of mean, range, and standard deviation are obtained, demarking points are obtained and subsequently, the t-test is applied to each of these parameters.

The study by Ahmed MM et.al showed the mean value of the pelvic segment was 63.31mm in males and 54.33 mm in females while the sacral segment was 62.0 mm in males and 50.35 mm in females and the Chilotic index was 116.30 in males and 110.5 in females¹¹. Charnalia et al showed in their study found that in the south Indian population, the mean value of the pelvic segment was 47.14mm in males and 59.90 mm in females while the mean value of the sacral segment was 65.72 mm in males and 56.74 mm in females and Chilotic index was 112.86 and 115.64 in males and females respectively¹².

Pal G P, Bose S and Choudary S (2004) tested the reliability of the chilotic line index and found mean values of index 109 in males and 89 in females. They also calculated mean ± 3 S.D values 75.49 – 142.51 and 51.11 – 1126.88 for male and female respectively. They obtained demarking points for males>126.88 and females <75.49. From this data, they can accurately identify only 9.09% male and 11.29% female hip bones¹³.  Jeneeta Baa et.al⁹ (2018) showed in their study the mean value of the pelvic segment and sacral segment along with the mean value of the chilotic index of males is 53.51 mm, 63.06 mm and 118.32mm, respectively and in females the same parameters were found to be 63.91 mm, 53.97 mm and 84.84 mm respectively. 

In the present study total of 178 adult human hip bones were examined for sexual differentiation using the chilotic line and chilotic line index. Among 178, 124 were male and 54 were female hip bones. The mean value of the chilotic line index in males is 120.22, and that of females is 97.58, with the value of males and females ranging between 83.07 – 151.1 and 72.3 – 160.8 respectively. Thus bones with a chilotic index above 115mm can be defined as a male hip bone. T-test is highly significant P<0.001. It is one of the reliable parameters for the identification of the sex of hip bones. Thus, the sex of the Hip bone can be assessed up to about 97% confidence with the help of “Chilotic line” and “Chilotic line Index” only.

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