Discussion
Although the mechanisms underlying the asymmetry of the human face has
been subject to comprehensive research, no conclusive results have been
obtained to date. Several factors including developmental or genetic
factors, as well as those related to soft tissue orientation, prenatal
stress, and environment (low temperature) have been described in the
literature (15, 16). One of the hypotheses proposed by Moss is that the
septal deviation has a negative impact on facial development, with the
affected side being less well-developed (17). Another hypothesis has
proposed that the nasal septum is also asymmetrical and deviated as a
result of the development of the facial bones (18, 19).
Hafezi et al. evaluated facial asymmetry in deviated noses and reported
that the left side of the nose, left half of the face, and left side of
the body were greater in size, and that the nose was deviated to the
less well-developed side (20). Furthermore, Ercan et al. (2008) found
higher dimensions in the anatomical structures forming the left half of
the face in a Turkish cohort. In our study, the bony nasal pyramid was
deviated to the right and left in 59.4% and 40.6% of those
participants with an asymmetric bony nasal pyramid, respectively.
Although the difference was statistically insignificant, a trend for
right-sided deviation was observed.
In a previous study examining whether nasal growth differed by sex, the
nasal growth was completed at 15.8 and 16.9 years of age in boys
respectively, indicating a statistically significant difference (21). In
another study evaluating the extent of variation in timing, duration,
and intensity of growth in the craniofacial complex during childhood and
adolescence, Nahhas et al. reported that, in male adolescents, as
opposed to females, the peak velocity of the anteroposterior growth of
the maxilla occurred earlier than 14 years of age, and that the growth
continued until the age of 20 years, although it was at a lower
rate(22). In the current study including male adolescents aged 15, 16,
and 17 years, the nasal bony pyramid deviation, caudal septal deviation,
and nostril asymmetry did not increase and, on the contrary, a minimal,
insignificant degree of reduction was observed. Based on these findings,
we can speculate that male adolescents in these age groups reach a
stable point during nasal growth.
Caudal septal deviations refer to deviations of the one-third caudal
portion of the nose. Although review of the literature reveals several
studies on problems (aesthetic and/or functional) associated with the
caudal septal deviations and proposing treatment recommendations, there
is no study available examining its incidence during adolescence
(between 15 and 17 years of age). The classification for septal
deviation proposed by Mladina et al. (1987) includes Type 1, 2, and 4
caudal septal deviations and allows a diagnosis to be established by
inspection and Cottle’s maneuver. In another study Marin and Mladina
(2001) reported that the overall incidence of Type 1, 2, and 4
deviations among patients aged between 15 and 18 years was 40.7%.
Although no significant correlation was observed with caudal deviations
and sex, Type 1 was the most common type with a significant decline with
aging. In the aforementioned studies, no data regarding the side of the
deviation were given. In contrast, 25.6% of the participants had caudal
septal deviation and, of these, 74.2% were to the right in our study.
Since septal deviation has an impact on the size of nostrils, it is not
surprising to observe smaller nostrils in participants with septal
deviation to the right. Similarly, in 75.5% of the adolescents with
asymmetric nostrils, the right nostril was smaller.
In general, questionnaires and performance studies are utilized to
evaluate the hand dominance. Among these, questionnaires are more
frequently used tools thanks to their practical nature. In this study,
we asked participants to choose one of their hand as dominant according
to daily tasks such as writing, use of knives and forks, throwing, and
tooth brushing. Some large-scale studies have reported a prevalence of
89.6% to 94.1% for right-hand dominance (23). Consistent with these
reports, 91% and 9% of our participants were right- and left-hand
dominant, respectively. Since nasal deviations without a major trauma
are thought to have developmental and genetic underlying mechanisms, we
attempted to evaluate the possible relationships between hand dominance
and nasal deviations in our study. To the best of our knowledge, there
is no study available investigating this potential link. Among our
adolescent boys cohort, 61.2% of those with a nasal deviation to the
right had right-hand dominance, while 58.3% of those with nasal
deviation to the left were left-hand dominant. Although these
associations were not statistically significant, a trend in nasal
deviations was noted toward the side of the hand dominance.
Furthermore, in those with caudal septal deviation to the right, 76.6%
were right-hand dominant, while 50% were left-hand dominant in those
with a deviation to the left. Again, these associations were not
significant. This might be due to a small number of adolescents with
caudal septal deviation and left-hand dominance. In our study, the
caudal part of the septum was evaluated through inspection, without the
use of any equipment (speculum, endoscope) or imaging studies such as
direct X ray or computed tomography. Inspection allows the assessment of
the nasal bony pyramid and caudal septum only. This examination method
was chosen on the basis of the fact that it was non-invasive and
associated with minimal discomfort, suitable for adolescents under 18
years of age with no history of trauma. Although inspection is
considered adequate for the accurate evaluation of the asymmetry,
quantitative measurements (speculum and endoscopic examination) and
imaging studies would allow better quantification of such conditions.
Another main finding of the present study is that 84.6% of those with
caudal septal deviation had nasal bone pyramid deviation to the right,
and 91.2% of those with a septal deviation to the left had nasal bone
pyramid deviation to the left. This finding supports the axiom “as the
septum goes, so goes the nose” proposed by Maurice Cottle and suggests
that the nasal septum also determines the direction of the external
deviation. In this context, it may be worth noting that the importance
of the cartilage septum on the development of the nose and maxilla was
underscored by Verwoerd and Verwoerd-Verhoef (24).
Nonetheless, there are some limitations to this study. First, no imaging
tool such as CT or nasal endoscopy was used for a more accurate
evaluation of the septal deviation. Determination of nasal septal
deviation was done by purely visual analysis, so there would be many
false negatives which would skew the data. Second, the hand dominance
was evaluated for the left and right hands and ambidexterity was
disregarded. In general, two tests are used to evaluate hand dominance:
one for self-report questionnaire and the other one for functional
ability and skills. In this study, however, hand dominance was evaluated
by questioning the preference of hand during daily living activities
such as writing. We used this method to improve the attention of
adolescents to the questionnaire. Also, the school setting did not allow
for a functional evaluation. Third,
this study does not cover girls
since it was conducted in schools where only boys attend. We are of the
opinion that it will be appropriate to include girls in the next studies
to obtain the correct results.