European Journal of Cardiovascular Medicine

Sex determination of unknown skeletal remains come across in forensic or archeological situations, is one of the prime tasks of experts like forensic anthropologists and bioarcheologists involved in such examinations ^[1].

Congenital sternal foramens can often be mistaken for bullet holes ^[2]. They are usually without symptoms but can be problematic if acupuncture in the area is intended^[3].

The quantum and duration of growth spurt, growth patterns, strength of muscular attachments and exposure to differential biomechanical loadings in two sexes etc., might be the factors responsible for the bones that exhibit good sexual dimorphism, which, in turn, make them suitable for sex determination ^[4] Whereas, the non-metric methods are simple, quick and easy to apply ^[5] though they are more subjective in nature with higher inter-observer errors, thus not considered suitable for forensic applications ^[6].

With the introduction of discriminant function analysis in forensic osteological studies, the subjectivity levels and the expertise needed has been reduced substantially ^[7] and even 100% sexing accuracy can be obtained from it. Though discriminant function analysis is extremely useful in sex determination of fragmentary or incomplete skeletal remains, ^[8] such estimates are not universal and are highly population specific ^[9].

In Indian context, the recovery of unknown human skeletal remains is common, probably because of increasing naxalite or terrorist massacres, clandestine murders, natural calamities like tsunamis, earthquakes, plane/train/road accidents, mafia conflicts, etc. Sexual dimorphism in human sternum has remained a matter of discussion among forensic anthropologists since long times. Both the morphologic as well as morphometric sterna features have been utilized in this endeavor; however, the quantitative metric analysis of sternum is preferred to the morphological observations as the former analysis is prone to statistical analyses.^[10] Few workers have used the individual or the combined length/s of sternum (as a ‘rule’) for estimating sex, while others have devised either identification, demarking or limiting points; or have calculated discriminant functions and regression equations based on such measurements for this purpose^[11]. Average maximum manubrial breadth in male as well as females of present study is significantly more than those reported by Atal et al.,^[12] for a Delhi population (India), but is significantly less than the Croatian and Spanish samples. By applying the multivariate linear discriminant analysis technique 92% male and 87% female sterna can be sexed correctly^[13].

According to Wenzel manubrium in the two sexes, is almost equal in length, but the Mesosternum is proportionally longer in males than the females. This led to enunciation of Hyrtl's law, according to which manubrio corpus index (sterna index) exceeds 50 in females and is less than 50 in male ^{[14, 13]}. In their study concluded that 100% female and 52.20% male specimens obey the law. However, the manubrium – corpus indices of one sex fall within the range of other sex in 95% cases.

Many studies ^{[15, 16]} have been done on determination of sex and stature by hand and foot length dimensions showing these indices to be poor indicators with limited practical value.

According to ^[17] conducted a study on the difference in the ratio between the length of manubrium and that of mesosternum in both sexes. His findings were supported by ^[18] and ^[19]. They stated that the ratio between the manubrium and mesosternum is 1:2 in the case of women and less in men (Hyrtl’s law).^[20] recorded that the mesosternum was longer and narrower in males than in females. For sexing the European sterna,^[21] formulated the 149 rule according to which a male sternum exceeded 149mm in length whereas the female sternum was less than 149mm. This rule was applicable to 77.6% males and 80.4% females for European sterna. ^[22] conducted a study on the sexing of the North Indian sterna and concluded that the first rule as stated by ^[21] was not applicable to Indian sterna, which were shorter than the European steerna.

In a study carried out on morphometric studies of x-rays of the sternum, sex determination of a sufficient certainty was possible using measurement of length and breadth obtained from x-rays of the human sternum if a wide range of dispersion is given. The given relations and formula are valid only when measuring the sternum of adults ^[23].

This study has been conducted on the total 100 subjects, 50 male (02-15 yrs) and 50 female (02-15 yrs) of healthy living children from general population of north India as well as in and around the Lucknow of Uttar Pradesh. After obtaining ethical clearance and informed consent form, the living subjects have been recruited from the healthy children of OPD, department of pediatrics at King George’s Medical University, U P, Lucknow. All the living subjects have been well informed about the nature of study. To prevent discrimination, living subjects have recruited for our study fulfilling inclusion criteria (male& female children, age 02 to 15 years, BMI less than 25 and no history of chronic disease, at least 1 year tenure, no use of medication other than analgesics during the month preceding data collection). The living subjects have been explained the procedure of study. For the morphometry of the sternum, following measurements have been taken in to consideration:

Length of manubrium: It has been measured from the center of suprasternal notch to the centre of the manubrio-sternal junction in mid sagittal plane. 

Length of mesosternum: It has been measured from the centre of manubrio-sternal junction to the centre of sterno-xiphoid junction in the mid sagittal plane.

Total length of sternum: It has been measured from the centre of jugular notch to xiphoid process in the mid sagittal plane. The above mentioned measurements have been further use to calculate various sternal size and indices according to the technique described by Ashley. Each linear measurement has been taken thrice on the anatomical position of the sternum using Mitutoyo-digital vernier calipers to the nearest millimeter with precision of 0.01 mm, according to definitions presented in and their average was recorded ^[21].

Statistical analysis:

Data were summarized as Mean ± SD (standard deviation), range (min to max) and median. Groups were compared by independent Student’s t test. Pearson correlation was done to assess association between variables. A two-tailed (α=2) p<0.05 was considered statistically significant. Analyses were performed on SPSS software (windows version 21.0). 

Basic characteristics:

(I). Female Children 02-15 yrs:

The basic characteristics of 02-15 yrs females are summarized in Table 1. The age of females ranged from 03-15 yrs with mean (± SD) 9.14 ± 3.08 yrs and median 9 yrs. The height, weight and BMI ranged from 70.56-136.89 cm, 12.39-41.29 kg and 8.14-31.87 kg/m² respectively with mean 112.48 ± 16.76 cm, 25.36 ± 9.26 kg and 20.02 ± 5.91 kg/m² respectively and median 111.85 cm, 24.19 kg and 19.89 kg/m² respectively. The chest circumference, waist circumference and hip circumference ranged from 34.18-70.42 cm, 37.52-66.58 cm and 35.89-75.41 cm respectively with mean 53.80 ± 6.87 cm, 50.92 ± 5.84 cm and 56.61 ± 7.36 cm respectively and median 54.94 cm, 51.50 cm and 57.09 cm respectively.

The mean length of manubrium, mesosternum and sternum ranged from 34.65-58.90 mm, 70.37-108.56 mm and 110.24-148.29 mm respectively with mean 44.47 ± 5.79 mm, 93.90 ± 7.92 mm and 138.38 ± 6.93 mm respectively and median 43.17 mm, 95.38 mm and 138.55 mm respectively.

(II). Male Children 02-15 yrs:

The basic characteristics of 02-15 yrs males are summarized in Table 2. The age of males ranged from 03-15 yrs with mean (± SD) 9.40 ± 2.95 yrs and median 9 yrs. The height, weight and BMI ranged from 78.69-158.39 cm, 3.19-41.39 kg and 2.06-39.38 kg/m² respectively with mean 129.87 ± 18.91 cm, 29.62 ± 8.94 kg and 17.77 ± 5.57 kg/m² respectively and median 129.82 cm, 30.52 kg and 16.72 kg/m² respectively. The chest circumference, waist circumference and hip circumference ranged from 46.37-68.36 cm, 42.36-64.23 cm and 40.63-80.84 cm respectively with mean 56.94 ± 5.43 cm, 53.03 ± 5.31 cm and 58.26 ± 7.02 cm respectively and median 57.07 cm, 52.96 cm and 58.36 cm respectively.

Table 1: Basic characteristics of 02-15 yrs females Children

Table 2: Basic characteristics of 02-15 yrsmales Children

Table 3: Inter correlation between variables in02-15 yrs femalesChildren(n=50)

• ns-p>0.05, *-p<0.05, **-p<0.01, ***-p<0.001

Table 4: Inter correlation between variables in 2-15 yrs malesChildren(n=50)

• ns-p>0.05, *-p<0.05, **-p<0.01, ***-p<0.001

The mean length of manubrium, mesosternum and sternum ranged from 39.57-56.71 mm, 95.02-121.54 mm and 149.23-168.76 mm respectively with mean 49.45 ± 3.45 mm, 106.71 ± 6.25 mm and 156.16 ± 5.26 mm respectively and median 49.62 mm, 105.58 mm and 156.38 mm respectively.

Correlation in 02-15 yrs females:

The inter correlation between variables in 02-15 yrs females is summarized in Table 3. Pearson correlation analysis showed a significant and negative (inverse) correlation of length of manubrium with BMI (r=-0.32, p<0.05), length of mesosternum with age (r=-0.30, p<0.05) and height (r=-0.31, p<0.05), and length of sternum with age (r=-0.42, p<0.01). Further, a significant and negative correlation was found between length of manubrium and length of mesosternum (r=-0.53, p<0.001) while a significant and positive (direct) correlation between length of mesosternum and length of sternum (r=0.70, p<0.001).

Correlation in 02-15 yrs males:

The inter correlation between variables in 02-15 yrs males is summarized in Table 4. Pearson correlation analysis showed insignificant (p>0.05) correlation of length of manubrium, mesosternum and sternum with all demographic characteristics (age, height, weight, BMI, chest circumference, waist circumference and hip circumference). However, a significant and negative correlation was found between length of manubrium and length of mesosternum (r=-0.54, p<0.001) while a significant and positive correlation between length of mesosternum and length of sternum (r=0.83, p<0.001).

The study was conducted on 100 subjects (50 male  children and 50 female Children). Anthropometric and morphometric parameters were measured for forensic purposes in all subjects and intercorrelated age, sex with their different part of sternum. Results from our study revealed that body weight, BMI, and abdominal circumference were in normal range. The finding suggests that osteometric evaluation of the sternum can be an effective method for identification of sex and age in the Lucknow population.

The inter correlation between variables in 02-15 yrs females is summarized in Table 3. Pearson correlation analysis showed a significant and negative (inverse) correlation of length of manubrium with BMI (r=-0.32, p<0.05), length of mesosternum with age (r=-0.30, p<0.05) and height (r=-0.31, p<0.05), and length of sternum with age (r=-0.42, p<0.01).The inter correlation between variables in 02-15 yrs males is summarized in Table 4. Pearson correlation analysis showed insignificant (p>0.05) correlation of length of manubrium, mesosternum and sternum with all demographic characteristics (age, height, weight, BMI, chest circumference, waist circumference and hip circumference). However, a significant and negative correlation was found between length of manubrium and length of mesosternum (r=-0.54, p<0.001) while a significant and positive correlation between length of mesosternum and length of sternum (r=0.83, p<0.001).

On the basis of observation and result in my present study it was fully supported and agree of the previous researchers,  who has done the work in measurement of sternum bone in cadaver and skeletal of human, because they told that the sterna has distinguish in different zone of India, as well as it is shorter than European country. The length of manubrium in adult was higher than children because the growth of sternum segment was completely develop in adult, but the development in male& female children is continuous in ratio of male adults. It indicates that ratio between the male& female children were fully supported to the previous research rule.

Further, a significant and negative correlation was found between length of manubrium and length of mesosternum (r=-0.53, p<0.001) while a significant and positive (direct) correlation between length of mesosternum and length of sternum (r=0.70, p<0.001).

This result and observation show that there was no eject explanation aboutlength of manubrium and length of mesosternum while a significant and positive (direct) correlation between length of mesosternum and length of sternum respectively.

According to observation and result we can discuss that previous study which was done by ^{[21] [24]}  which agreed with our findings for assess the intercorelation in stage of development and sex between living male and female children through measurement  of sternum bone in lucknow of U.P. and therefore further need for future study and research  related to sternum.

The inter correlation of age and sexes with segment of sternum between 02-15 years male and female living children in population of Uttar Pradesh significant and negative correlation was found between length of manubrium and length of mesosternum while a significant and positive correlation between length of mesosternum and length of sternum  respectively.

Acknowledgement

The authors are grateful to all subjects who participated in this study.  I would like to thanks Dr. M.P. Negi, Statistician in Central Drugs Research Institute (CDRI), Lucknow for his Statistical analysis and cooperation, and I would like to give specially Thanks Dr. Vimal Modi, Professor & Head, Department of Anatomy, Index medical college, hospital & Research Centre, Malwanchal University Indore and Dr. Navneet Kumar, Professor & Head, department of Anatomy, King George’s Medical University, U.P., Lucknow for developing this hypothesis, cooperation, and conducting this research work.

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