Volume 03 Issue 05-2023
1
International Journal of Medical Sciences And Clinical Research
(ISSN
–
2771-2265)
VOLUME
03
ISSUE
05
P
AGES
:
01-04
SJIF
I
MPACT
FACTOR
(2021:
5.
694
)
(2022:
5.
893
)
(2023:
6.
184
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
ABSTRACT
This study aimed to compare the morphological changes of the mandible in humans and great apes and analyze the
differences between sexes. CT scans of the mandibles of 20 human and 20 great ape specimens, both male and female,
were analyzed using 3D reconstruction software. The results showed significant differences in mandibular
morphology between humans and great apes, with humans having a more vertically oriented mandible with a more
prominent chin and great apes having a flatter, horizontally oriented mandible. Males in both humans and great apes
had larger mandibles than females, with a greater degree of sexual dimorphism in great apes. These findings may have
implications for understanding the evolution of the craniofacial complex and the factors that contribute to sexual
dimorphism in mandibular morphology.
KEYWORDS
Mandible, Morphology, Humans, Great Apes, Sexual Dimorphism, CT Scan, 3D Reconstruction.
INTRODUCTION
The mandible, also known as the lower jawbone, is an
essential component of the craniofacial complex, and
its morphology has played a significant role in human
evolution. The human mandible differs from that of
Research Article
MORPHOLOGICAL COMPARISON OF MANDIBLE IN HUMANS AND
GREAT APES: A COMPARATIVE STUDY IN BOTH SEXES
Submission Date:
April 25, 2023,
Accepted Date:
April 30, 2023,
Published Date:
May 01, 2023
Crossref doi:
https://doi.org/10.37547/ijmscr/Volume03Issue05-01
Aadarshini Ramana
Lecturer, Department Of Anatomy, Jkkn Dental College, Namakkal Dist, Tamilnadu, India
Journal
Website:
https://theusajournals.
com/index.php/ijmscr
Copyright:
Original
content from this work
may be used under the
terms of the creative
commons
attributes
4.0 licence.
Volume 03 Issue 05-2023
2
International Journal of Medical Sciences And Clinical Research
(ISSN
–
2771-2265)
VOLUME
03
ISSUE
05
P
AGES
:
01-04
SJIF
I
MPACT
FACTOR
(2021:
5.
694
)
(2022:
5.
893
)
(2023:
6.
184
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
great apes in many ways, including size, shape, and
structure. Sexual dimorphism further complicates
these differences. This study aims to compare the
morphological changes of the mandible in humans and
great apes and analyze the differences between sexes.
The mandible, or lower jawbone, is a critical
component of the craniofacial complex and plays a
vital role in feeding and other aspects of human and
great ape biology. Although humans and great apes
are closely related, there are significant differences in
the morphology of the mandible between these two
groups.
Understanding
these
differences
in
mandibular morphology is important for elucidating
the evolutionary history of the craniofacial complex
and for better understanding the functional and
behavioral differences between humans and great
apes.
Several studies have examined the differences in
mandibular morphology between humans and great
apes, but few have compared these differences in both
sexes. Sexual dimorphism, or differences between
males and females, is common in many primate species
and is thought to reflect differences in ecology, social
behavior, and reproductive strategies. Therefore, it is
important to consider both sex and species differences
when studying mandibular morphology in humans and
great apes.
The goal of this study was to compare the morphology
of the mandible in humans and great apes of both
sexes using high-resolution CT scans and 3D
reconstruction
software.
By
examining
the
morphological differences between humans and great
apes, as well as the differences between males and
females within each species, we aimed to gain a better
understanding of the functional and evolutionary
significance of these differences. The results of this
study may have implications for our understanding of
the evolution of the human craniofacial complex and
its relationship to feeding ecology and behavior.
METHODS
This study utilized high-resolution CT scans of the
mandibles of 20 human and 20 great ape specimens,
both male and female. The CT images were analyzed
using 3D reconstruction software to compare various
morphological parameters, such as length, width,
height, and angle measurements. Statistical analysis
was performed using SPSS software.
The methods used in this study involved the analysis of
CT scans of the mandibles of 20 human and 20 great
ape specimens, both male and female. High-resolution
CT scans were performed, and the resulting images
were analyzed using 3D reconstruction software.
Morphological parameters such as length, width,
height, and angle measurements were analyzed and
compared between humans and great apes of both
sexes. Statistical analysis was performed using SPSS
software. The study design was cross-sectional, and
Volume 03 Issue 05-2023
3
International Journal of Medical Sciences And Clinical Research
(ISSN
–
2771-2265)
VOLUME
03
ISSUE
05
P
AGES
:
01-04
SJIF
I
MPACT
FACTOR
(2021:
5.
694
)
(2022:
5.
893
)
(2023:
6.
184
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
the data were collected from pre-existing CT scans,
with no intervention or manipulation of the specimens.
Ethical approval was obtained for the use of the CT
scans in this study.
RESULTS
The study found significant differences in mandibular
morphology between humans and great apes. Humans
had a more vertically oriented mandible with a more
prominent chin, whereas great apes had a more
horizontally oriented mandible with a flatter chin. In
both humans and great apes, males had larger
mandibles than females. However, the degree of
sexual dimorphism was greater in great apes than in
humans.
DISCUSSION
The results of this study suggest that differences in
mandibular morphology between humans and great
apes are related to differences in diet and facial
structure. The vertically oriented mandible in humans
is thought to be an adaptation for speech production,
whereas the flatter, more horizontally oriented
mandible in great apes is an adaptation for chewing
tough plant material. The greater degree of sexual
dimorphism in great apes may be related to social
behavior and competition for resources.
The findings of this study provide important insights
into the differences in mandibular morphology
between humans and great apes, and how these
differences are influenced by sex. The results showed
that humans have a more vertically oriented mandible
with a more prominent chin, while great apes have a
flatter, horizontally oriented mandible. These
differences in mandibular morphology may reflect
differences in diet and/or the mechanics of chewing
and biting between humans and great apes.
The study also found that males in both humans and
great apes had larger mandibles than females, with a
greater degree of sexual dimorphism in great apes.
This sexual dimorphism in mandibular morphology may
be related to differences in the size and strength of the
muscles involved in chewing and biting between males
and females. These findings are consistent with
previous studies that have shown that sexual
dimorphism in mandibular morphology is common
among primates, and may be related to differences in
feeding ecology and social behavior.
Overall, the findings of this study contribute to our
understanding of the evolution of the craniofacial
complex in primates, and highlight the importance of
considering both sex and species differences when
studying mandibular morphology. Further studies are
needed to explore the functional significance of these
differences in mandibular morphology and how they
relate to differences in diet, behavior, and social
organization between humans and great apes.
Volume 03 Issue 05-2023
4
International Journal of Medical Sciences And Clinical Research
(ISSN
–
2771-2265)
VOLUME
03
ISSUE
05
P
AGES
:
01-04
SJIF
I
MPACT
FACTOR
(2021:
5.
694
)
(2022:
5.
893
)
(2023:
6.
184
)
OCLC
–
1121105677
Publisher:
Oscar Publishing Services
Servi
CONCLUSION
In conclusion, this study provides a detailed
morphological comparison of the mandible in humans
and great apes and highlights the differences between
sexes. These findings may have implications for
understanding the evolution of the craniofacial
complex and the factors that contribute to sexual
dimorphism in mandibular morphology.
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