The Significance of Sternal Measurements for Sex Differentiation

This literature review examines the role of sternal measurements in determining sex differences in individuals, a crucial aspect of anthropological and forensic investigations. The review synthesizes findings from various studies, including those by Dwight (1890), Duyar et al. (2018), and Saraf et al. (2018), which highlight the sternum's significance in estimating height, age, and sex. These studies demonstrate that sternum length and specific measurements, such as the manubrium-body index, exhibit sexual dimorphism, with males generally having longer sterna. The review also discusses the use of CT images and artificial neural networks for sex prediction based on sternal measurements (Oner et al., 2019). Further, the analysis includes studies comparing sternal and clavicular measurements (Sehrawat, 2018) and meta-analyses quantifying the association between sternal parts and stature (Yammine and Assi, 2017). The research emphasizes that while the sternum is a reliable indicator, variations exist across populations, and that a combination of measurements often yields the most accurate results for sex estimation in forensic contexts. The review concludes by highlighting the importance of developing robust osteometric standards for fragmented and complete bones to facilitate individual identification.

Running head: LITERATURE REVIEW
LITERATURE REVIEW
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1LITERATURE REVIEW
The sternum, commonly referred to as breastbone refers to a flat bone that is present
at the central position of the chest. The structure of the sternum comprises of three major
parts that are namely, the manubrium, the body, and the xiphoid process. While the top
region of the sternum provides support to the clavicles, also referred to as the collarbones, the
edges are joined with the costal cartilages that are present in the initial two ribs. Furthermore,
this breastbone has the shape of a necktie and plays an important role in protecting the inner
organs namely, the lungs, heart and blood vessels (Apple and Bassett 2018). At the time of
conducting anthropological and forensic investigation, the biological profile of an individual
is generally determined by sex, ancestry, age, and stature. Nonetheless, several persons might
share the similar profile. Therefore, observation of separate traits can produce useful evidence
and facilitate identification. This literature review will determine the role of sternal
measurements in determining sex differences between individuals.
Time and again it has been postulated by several researchers that sternum length is
related to different anthropometric parameters of the human body. The significance of
sternum as an important indicator of height, sex and age was first highlighted by Dwight,
(1890) who elaborated on the fact that length of the sternum, including the ensiform was an
estimated was 1/7.78 the overall height in males and 1/8.04 the height in females.
Nonetheless, there was no direct correlation between the length of the breast bone and height.
The researcher also illustrated that entire length of the sternum intensifies with an increase in
height in each group following a certain order. Furthermore, on conducting an analysis of the
sternum length, it was also found that the sternum is shorter amid females, in proportion to
height, when compared to their male counterparts. However, it was also found that the length
is comparatively smaller among females who have a shorter height, compared to taller
females. The link between sternum and age was further elucidated by the fact that in young
age, the sternum generally exists in the form of a broad cartilage strip between the body and

2LITERATURE REVIEW
the manubrium, and the first piece of the body was found to be dissimilar from the rest of the
portions. Further evidences presented by the researcher also demonstrated that in females
who were aged 25 years, the sternum was a single piece of bone, and the body and the
manubrium remained united, wih a distinct ensiform. Likewise, while examining males,
while clear distinction was observed between the manubrium, ensiform and body amid some
people, they were ossified in others, thereby showing contrasting features. The findings can
be supported by those presented by Duyar, Pelin and Atamtürk (2018) who elaborated that
age, sex, and body height are of major prominence in the identification of persons in
medicolegal examinations. Body height can be considered more precisely from the
dimensions of chief long bones that are located in lower and upper limbs. Furthermore, when
there exists an absence of of limb segments or long bones present in extremities, dimensions
of face, head and sternum were considered as best predictors. On conducting a univariate and
multivariate regression analysis, the researchers found that length of the sternum
demonstrated a comparatively high association with body height. Results from the 108
participants suggested that the variables that were most highly associated with body height
were namely, sternum length and total face height, respectively. This was followed by the
association with morphological face height. Results from the statistical analysis revealed that
mean sternum length (mm) in group I and group II was 206.31 and 203.31, respectively.
Furthermore, pearson correlation coefficient between sternum length and body height was an
estimated 0.338. Hence, the researchers concluded that no single measurement related to
sternum, head or face was sufficient for determining the body height of a particular person in
different anthropological or forensic cases.
Sarafet al. (2018) also focused their investigation on the fact that identifying the dead
has been acknowledged as a significant step in examining decomposed, mutilated, and
unknown human remains. In other words, the research was based on the fact that

3LITERATURE REVIEW
confirmation of biological profile of a body is the dominant issue in such a situation, and
stature approximation remains one of the significant measures in this respect. The
contemporary investigation was commenced to conduct an evaluation of human stature from
diverse portions of the sternum. The researchers obtained a sample of 100 sterna from
persons during the medicolegal post-mortems. Measurement of the dead and numerous
dimensions of the sternum were conducted, followed by performing the student's t-test, with
the aim of determining gender differences in height and sternal measurements. The
researchers used Karl Pearson's correlation, quadratic and linear regression models for
estimating the correlation between stature and sternal dimensions. It could be deduced from
the results that the measurements were found to be suggestively superior in me, when
compared to their women counterparts. Best correlation of stature was found with the joint
length of sternum, amid men (R = 0.894), women (R = 0.859), and for the entire sample
(R = 0.891).
The results also illustrated that the models that had were consequent of stature
approximation from joint length of the sternum demonstrated an increased likelihood of
providing most precise approximations of height in anthropological and forensic cases, in
comparison to mesosternum and manubrium. Exactness of stature assessment further
augmented with quadratic models that were derivatives of mesosternum amid men, in
addition to the joint length of sternum amid males and females, in contrast to linear
regression models. These findings were also in accordance to the results obtained from an
investigation by Oneret al. (2019) that was based on sex estimation using length of the
sternum. The researchers based their investigation on the fact that in addition to the cranium,
pelvis, and phalanges, the sternum has also gained recognition as an important indicator of
sex identification during post-mortem. The researchers used thin-slice thoracic CT images
that corresponded to 422 cases (213 women, 209 men) who were aged in the range of 27–60

4LITERATURE REVIEW
years, and these images had been organised in an orthogonal plane. This was followed by
conducting an analysis of the MSL, XPL, CSL, and SA measurements, using
a multilayer artificial neural network, which in turn was based two hidden layers and
stochastic gradient descent (SGD) for optimization. The findings suggested that while CSL,
MSL, and XPL were longer, the SA was wider amid males (MSL p = 0.000, CSL p = 0.000,
XPL p = 0.000, SA p = 0.02). Furthermore, taking into consideration the two hidden layers
present in artificial network having 20 and 14 neurons in between, sex prediction accuracy
was an estimated 0.906. On running a bootstrap, 0.90 specificity (Spe) value was estimated,
thus highlighting the fact that artificial neural network can be used to determining sex, by
calculating sternum length.
Bhuvaet al. (2016) also tried to assess the reliability of using sternal index for
determining sex of individuals. They illustrated that the breast bone was studied for
determination of sex as an individual parameter by Wenzel in 1788. Also referred to as
manubrio-corpus index, the sternal index acts as a significant and recurrently identified
parameter for sex determination. The researchers conducted an investigation using 100 cases
that were obtained from the P.D.U. Hospital and Medical College, Rajkot mortuary from
January 2010-August, 2011, using sternum bones that had been obtained from cadavers
procured for post-mortem examination. On analysing the cadavers, they found that mean
sternal index among men was 52.39 mm with an SD of 7.70, which in turn was less than
60.12 mm index among women with SD of 8.63. It was further found that there existed an
overlapping region in sternal index in both sexes from 39.33-73.51 mm. Furthermore, the
minimum length of sternum found among men was 74.57 mm, when compared to 61.05 mm
amid women. This was in contrast to the maximum sternum length that was 111.58 mm and
84.49mm among men and women, respectively. While all male observations could be
categorised in this range, an estimated 6.90% female observations were beyond the range.

5LITERATURE REVIEW
This made the researchers conclude that variations in sternal index were attributed to
different ethnicities, geography and racial distribution. This was further supported by findings
from Yammine and Assi (2017) who conducted a meta-analysis for quantifying the evidences
that shed light on association between the length of sternum parts and body stature. The
analysis comprised of nine studies that were based on 1118 sternal bones and results
suggested that the length of the meso-sternum, which comprised of the manubrium and the
body generated the best association with human stature; 53.5% and 55.42% for males and
females, respectively. In addition, it was estimated that the full length of the sternal was the
second best variable and demonstrated an association of 44.3% for males and 55% for
females, respectively. On conducting a subsection analysis of different post-mortem reports a
greater association of 58.2% was obtained for the meso-sternal length, in contrast to least
association values for manubrium and body length. Excluding the body length, women
exhibited an increased association, when compared to their men counterparts, in relation to
stature and other sternal lengths. While the researchers considered the meso-sternal length as
the most associated variable with height, other lengths of the sternal was also needed to be
measured with carefulness when approximating stature.
The article on Estimation of sex from sternal measurements shows a comprehensive
analysis of sternal sexual dimorphism where the sample setting was set with modern Western
Australian individuals. The primary objective of the study was to develop statistical robust
standards for sex determination (Franklin et al. 2012). Standard practice of determining sex
and other characteristics of an unknown, decomposed or skeletal remains involves analysing
and identifying certain attributes of the skeleton to facilitate individual identification. Sex
determination is an important factor in forensic science for the accurate identification of
individuals matching identity and for estimating and determining other biological features
like ancestry, stature and age. The study shows that the peri- and post mortem impacts the

6LITERATURE REVIEW
availability of a complete skeleton or individual parts for examination. It is critical to find
reliable and accurate osteometric standards for the assortment of fragmented and complete
bones. According to the authors, the skull is considered to be the most sexually dimorphic
region of the human Skeleton (Franklin et al. 2012). It is mostly favoured for sex
determination. However, studies show evidences on sternum to be sexually dimorphic and
shows an overall accuracy that is above 80% in populations. The main finding of the study
was the sternum of a human skeletal to be the most reliable element in sex determination
(Franklin et al. 2012).
Another study also agrees with the fact that sternum are important for sex
determination but research findings opened another pathway for estimation of sex and found
clavicle, the bones of anterior thoracic skeleton, to be more reliable and accurate for
determining sex (Sehrawat, 2018). To find out the most reliable source, a comparison of both
of these bones was necessary to be carried out. The research adopted a methodology of
assessing the current sustainability of these tow bones of the same individual and were
collected from 252 males and 91 females for sex determination from whom medico-legal
autopsy was conducted with the help of forensic specialists of the Branch of Scientific
Medicine of the Postgraduate Institute of Medical Education and Research (PGIMER) which
is located in the region of Chandigarh, situated in India (Sehrawat, 2018). A single piece of
both of the sternum and the clavicle was removed during the post mortem procedure by slits
in the sterno-olecranon, acromioclavicular, and costo-sternal joints, along a the route of
standard linear midline slit. The sternum was detached from the 2 clavicles through a cut on
the sternal margins of the cartilages articulating the equivalent ribs. The detached bones were
simmered and cleaned for measuring. The mean values showed to be higher in males than
compared to those of females; for both the clavicular and the sternal. Through the product
index and measuring the mid circumference and the weight as well as the length of the

7LITERATURE REVIEW
sternum and clavicle it was found that they are the highest contributors of sex dimorphism.
The findings of the study also showed least differences between the sexes by the clavicular
robusticity and length of the manubrium. Bilateral symmetry was carried out in the
methodology to support the clavicular dimensions since it was found to show a lot of lateral
alterations as the average mass of the right positioned clavicle. The chart of the dimorphism
was seen to be extreme for the mass of clavicle being trailed by the product index, mid-
clavicular perimeter, length of the mesosternal and the joint sternal. The main finding of the
study shows that the substantial sexual dimorphism was observed in linear proportions of
both the clavicle and sternum. The product index of the clavicle as well as a joint sternal
length of sternum was discovered to be sexually dimporphic. Therefore, it was concluded in
the above study that the clavicle is more accurate and reliable for sex determination in human
skeleton (Sehrawat, 2018).
A research conducted on sex estimation from sternal measurement used
Morphometric analysis of sternum through Multidetector Computed Tomography for
achieving high accuracy in sex determination (Ekizoglu et al. 2014). The study encompasses
morphometric analysis of sternum achieved in computed tomography scan for determining
sex (Ekizogluet al. 2014). Other attributes measured from the analysis includes Meso-
sternum length, Manubrium length, Sternebra 1, and Sternebra 3 width as well as the sternal
index was measured. The differences in sexes were determined and evaluated by
discrimination analysis and receiver operating characteristic (ROC) analysis. The sternal
measurement of male was found to be significantly higher than that of females, whereas,
sternal index was found to be low in males. The research showed that computed topography
analysis of sternum gives important information on the sex determination (Ekizoglu et al.
2014). The study showed evidences supporting the Morphometric analyses of the sternum to
be most effective in determining sex from the human skeleton. There are studies that have

8LITERATURE REVIEW
provided sufficient evidences and proved that Anthropometric studies of skeleton structures
gives important information in the individual identification process. Post mortem
examination of skeletal elements provides information on the sex determination (Ekizogluet
al. 2014). The morphometric analysis can be carried out by directly measuring the dry bone
and through radiological methods during the post mortem events. The study was set in a
setting to facilitate the reliability and the utility of morphometric analysis of sterna for sex
determination. The research gave new findings incorporating the mean values of Manubrium
length, Mesosternum length, Sternebra 1 width, Sternebra 3 width and Sternal index was
found to be higher in females. It was also found in the study that the mean measurement
values significantly varies according to sex, standard deviations and p value. The study
concluded that a sternal morphometric analysis provides information on sex determination
and found to be 80.2% accurate in females and 80.9% in males (Ekizoglu et al. 2014).
A research paper by Macaluso and Lucena 2014, demonstrated that sternal
measurements recorded from the posteroanterior digital radiographs of the chest plate
(Macaluso and Lucena 2014). The findings of the study suggested that the linear dimensions
of the manubrium and mesosternum, sternal area, and sternal index are sexually dimorphic
and sex can be determined from them. The study shows that these discriminant variables,
both alone, and in combination are associated with sex determination and gives an accuracy
greater than 80.0% and an associated sex biases below 2.0%. The study settings was set in the
Forensic Pathology Service at the Institute of Legal Medicine in Seville, Spain, for
postmortem examination between August 2012 and July 2013. The samples which were
analyzed includes sterna of 116 people comprising of 65 men and 51 women who were
definitely recognised during the period of autopsy and had documents related to the medical
conditions and personal identification that provided different data such as birth date
(Macaluso and Lucena 2014). The chest plate analyzed consisted of the sternum, medical

9LITERATURE REVIEW
ends of the first through seventh ribs and costal cartilages were excised during postmortem
event. After removing the parts, calibrated digital radiographs of the chest plate for every
individual were obtained by using the Carestream Direct View Vita CR image acquisition
and processing system (Macaluso and Lucena 2014). The same processes was applied for the
radiographs having a posterior projection set at a focus distance of 100 cm and the exposure
parameters are set at 60 kVp and 6.3 mAs (Macaluso and Lucena 2014). A set of standards
were the recorded from digital images with the help of measurement tools, computer based
image analysis program along with radiographic system (Macaluso and Lucena 2014). It was
also found in the study that the mean values from the sternal index was found to be
significantly dimorphic, while, corpus stemi index do not differ much between the different
sexes. Therefore, these two parameters were not included in the analysis process. The study
demonstrated the osteometric analysis of the sternum to be an accurate and an effective
method for determining adult sex which was conducted within the Spanish population. The
study shows that most of the sternal dimensions and indices are sexually dimorphic. The
human remains such as the skeletons recovered from the forensic departments helped in
reiterating the efficiency of the sternum in determining the sex of human. The research also
shows evidences supporting population specific nature osteometric standards for
measurement of the sternal as the mean values that generally differ in both the sexes.
Therefore, the study shows that the osteometric calculations, thus, deliver an efficient and
significant method for estimating sex within the sample population group, especially in the
circumstances where the extremity pelvis or bones not well-maintained or conserved
(Macaluso and Lucena 2014).
The above-mentioned research articles mentioned the importance of sternal bone
measurement for the sex determination process especially used in forensic science. Further,
the paper by Ramadan et al. (2010) mentioned about the way the sternal measurement and

10LITERATURE REVIEW
length could be used to identify the sex of the body. Therefore, it is important to understand
the way sternum and the fourth rib measurement could be used for the sex determination in
which the tomography of the chest would be calculated using the multislice computed
tomography measurement. In this aspect it should be mentioned that metric measurement is
one of the most crucial aspect which is used for sex determination in tomography sex
determination. This is because Cox et al. (2015) mentioned that usage of metric measurement
would be easier on the dried bones and it is estimated that the results found in such processes
are effective in determining the result. Hence, the primary aim of the researchers of this paper
was to understand the accuracy of the sternal measurement process usage for sex
determination by comparing it which the Chest Multislice Computed Tomography (MSCT)
so that with the developed formula, the calculation and accuracy of the measurement could be
identified (Ramadan et al. 2010). In this research, total 340 patients were included and they
were assessed for their sternal bone length measurement, and the distance between this and
the fourth rib could be identified (Ramadan et al. 2010). The results obtained from this
research study indicated that the left fourth rib width is much more accurate in sex
determination than the right fourth rib width. Hence, this paper concluded that sex
determination of the skeleton with fragmented bones, which is termed as the most difficult
aspect of forensic science could be achieved by using different radiological methods such as
MSCT (Ramadan et al. 2010).
To understand the effectiveness and the positive and negatives of this research
findings, the research article of Abdelaleem, Younis and Kader (2016) should be discussed as
the aim of this research was associated with the research findings collected from Ramadan et
al. (2010) and aimed to understand the effectiveness and reliability of Three dimensional
Multislice Computed Tomography or 3D MSCT analysis for the sex determination of
Egyptian live samples. As per the researchers, the application of 3D MSCT is widely used for

11LITERATURE REVIEW
the identification of sex, age and gender in the forensic field however, the reliability and
accuracy of this tests are not performed regularly, and that affects the reliability of finings.
For this identification and determination, the researchers included 60 adult Egyptians in the
process and in this process researchers analyzed their manubrium length, sternal length and
width. The results indicated that 88% accurate results were observed in case of 3D- MSCT
and the accuracy of findings were approximately 96%, 95%, 73% with respect to the
inclusion of chest measurement, sternal measurement and width between the right and left
fourth rib respectively (Abdelaleem, Younis and Kader 2016). Hence, from the analysis the
researchers indicated that with involvement of chest measurement of the subjects, they were
able to observe 96% accurate results (Abdelaleem, Younis and Kader 2016). Therefore, from
this article and the research findings, it is clearly evident that application of sternal
measurement with three different approaches is useful in determining the sex, age and other
identification associated aspects of patient (Abdelaleem, Younis and Kader 2016).
Another research was conducted by Hunnargi et al. (2008) which aimed completely to
understand the effectiveness of this research process and determine the role of MSCT in
accurate estimation of the sternal measurement. This paper highlighted and identified few
crucial and critical aspects of the sternal measurement and sex determination ideal for
forensic science as it highlights accuracy and reliability associated aspects for the application
of this measurement method and mentioned the comparative analysis between this and other
traditional methods used for such purposes in forensic science. As per Castillo-Peinado and
de Castro (2017), sex determination is one of the critical aspect for forensic science as
depending upon this the accuracy of the investigation is measured. As the other research
articles mentioned that male sternal measurement is significantly more than that of the female
sternal length, this paper also highlighted this aspect (Castillo-Peinado and de Castro 2017).
However, this study was one of the leading research processes that identified the role of