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Original Research
Localization of mandibular foramen relative to landmarks in
East Indian mandibles
Kumari Sandhya, Bhoopendra Singh1, Namita Lugun, Renu Prasad
Departments of Anatomy
and 1Forensic Medicine and
Toxicology, Rajendra Institute
of Medical Sciences, Ranchi,
Jharkhand, India
Received
: 08‑08‑15
Review completed : 06‑09‑15
Accepted
: 09‑12‑15
ABSTRACT
Context: The position of mandibular foramen (MF) is an important anatomical landmark for
effective anesthesia in dentistry for many procedures, including dental extraction from the lower
jaw and putting mandibular implants. Several causes have been examined in this context, and
the uncertainty in the location of the MF has been examined to be a major factor for the high
failure rate of anesthesia and complications of the orthodontic procedure.
Aims: The purpose of this study was to examine and analyze the position of the MF relative to
six bony landmarks on the ramus in the population of Jharkhand.
Subjects and Methods: The different parameters were measured in 30 dry adult’s mandibles
that were obtained from the Department of Anatomy. The data were tabulated and statistically
analyzed.
Statistical Analysis Used: Paired t‑test.
Results: The mean distance between the MF and the respective landmarks was noted
as 16.00 ± 3.50 mm for the anterior border, 10.21 ± 2.34 mm for the posterior border,
20.48 ± 3.89 mm for the superior border, 24.15 ± 4.97 mm for the inferior border, 33.46 ± 6.08 mm
for the condyle, and 12.31 ± 4.88 mm for the internal oblique ridge for the right side. On the
left side, these distances were 16.27 ± 3.9 for the anterior border, 10.28 ± 5.24 for the posterior
border, 20.15 ± 3.8 for superior border, 24.86 ± 4.04 for inferior border 32.48 ± 4.73 for condyle,
and 10.93 ± 4.06 for the inferior oblique ridge. Statistically, there was no significant difference
in the distance to either side from selected 5 landmarks, the only exception being the condyle.
Conclusions: Condyle and internal oblique ridge have been shown to be two new landmarks that
may be used to find MF. Bilateral symmetry has been shown for all landmarks except for condyle.
Key words: East Indian mandibles, mandible, mandibular condyle, mandibular foramen
Mandibular foramen (MF) is an opening on the internal
surface of the ramus that leads into the mandibular canal.
This canal curves downward and forward in the body to
the mental foramen.[1] The inferior alveolar vessels and
nerves enter through the MF, traverse the canal, providing
branches to all teeth and exit through the mental foramen
as mental nerve and vessel.[1] MF is an important anatomical
landmark not only for oral maxillofacial surgery like
sagittal split osteotomies done to reposition the mandible
Address for correspondence:
Dr. Bhoopendra Singh
E‑mail: [email protected]
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in prognathism and retrognathia[2] but it is also significant
in connection with effective anesthesia in dentistry while
doing the inferior alveolar nerve block (IANB).[3]
It has been observed and reported by different researchers
that the main complications encountered during sagittal split
osteotomies are hemorrhage, injury to the neurovascular
bundle, undesired fractures, and bone necrosis when the
proper location of MF is not clear. Hence, a thorough
knowledge of the MF and ramus is essential for orthodontic
surgeries too.[4]
This is an open access article distributed under the terms of the Creative
Commons Attribution-NonCommercial-ShareAlike 3.0 License, which allows
others to remix, tweak, and build upon the work non-commercially, as long as the
author is credited and the new creations are licensed under the identical terms.
For reprints contact: [email protected]
PMID:
***
DOI:
10.4103/0970-9290.176917
How to cite this article: Sandhya K, Singh B, Lugun N, Prasad R. Localization
of mandibular foramen relative to landmarks in East Indian mandibles. Indian
J Dent Res 2015;26:571-5.
© 2015 Indian Journal of Dental Research | Published by Wolters Kluwer - Medknow
571
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Sandhya, et al.
Localization of mandibular foramen in East Indian mandibles
A study conducted by Meechan[5] in 1999 and observed
that the failures of anesthesia may stem from both the
operator and patient dependent factors. Such factors range
from a choice of technique to anatomical, pathological, and
psychological reasons. There are many articles published
in various scientific journals, describing the importance of
the anatomical structures in relation to the MF relevant to
successful mandibular anesthesia. A high failure rate still
persists for this technique that has been reported by many
workers like Potocnik and Bajrovic[6] have estimated the
failure rate of IANBs to be approximately 30–45%.[6] While
according to Shah et al.[7] the failure rate of IANBs was found
to be approximately 20–25%.[7]
Thangavelu et al.[8] have described the significance of
localization of MF in an IANB.
Studies have shown the racial differences in the anatomy of
the mandible. The literature contains conclusive evidence
that significant metric, morphological, and biological
differences are present among the three major racial
phenotypes, caucasoid, mongoloid, and negroid.[9,10]
There are significant differences reported on the location
of MF among different racial groups.[11‑13]
The aim of the study is to determine the precise location
of the MF in relation to the borders of the mandibular
ramus and to locate the quadrant of the ramus in which the
mandible foramen is located in the East zone of the Indian
population (Jharkhand).
Objective
The purpose of this study was to evaluate four broadly
studied bony landmarks and investigate two newly selected
bony landmarks relative to MF to assist the process of IANB.
It was also sought to determine whether bilateral symmetry
existed for each of these landmarks with respect to the
position of the MF.
SUBJECTS AND METHODS
The study was conducted on a sample set of 30 dry mandibles
of both sexes, available in the Department of Anatomy. This
included 26 dentulous and 4 edentulous bones. The various
landmarks used for measurements are illustrated in Figure 1.
The distance was measured to the nearest of 0.1 mm using
Vernier Caliper. To define the distance from MF each
landmark, point to point measurements were taken between
the midpoint (center) of the foramen and the closest point
on the respective landmark.
H0: There is no difference between the distance from the
chosen landmark to the MF on the right side and the left
side.
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Figure 1: Medial surface of the ramus of the mandible showing various
landmarks used for measures. F = mandibular foramen; A = Anterior
border; P = Posterior border; S = Superior border; I = Inferior border;
C = Condyle; R = Internal oblique ridge
HA: The distances from the chosen landmark to the MF on
the right side and the left side are not equal.
Data were analyzed using SPSS version 10 for Windows
(SPSS Inc., Chicago, IL, USA). Paired t‑test was used to
compare the left and right sides with the t‑value and
P < 0.05 considered significant. Quantitative data are given
as mean ± standard deviation (SD) and standard errors were
calculated for the six data sets. The paired t‑test was applied
for testing the null hypotheses for the data sets.
RESULTS
The minimum, maximum, and mean distance of the MF
from the closest point on the anterior border is detailed
in Table 1. This includes data from both the left and right
side of the mandible. Table 1 also includes the SD and
standard error for the dataset, as well as the t‑value and
P value for statistical analysis. It shows that the mean
distance between the MF and the anterior border is 16.00
with SD 3.50, standard error 0.64 mm on the right side
and 16.27 mm with SD 3.9 and standard error 0.73 mm
on the left side. The analysis led to the acceptance of the
null hypothesis.
There may be bilateral symmetry for the distance between
the anterior border and MF as no evidence was found against
H0 at the 1% level of significance.
It shows that the mean distance between the MF and the
posterior border is 10.21 mm with SD 2.34 mm and standard
error 0.43 mm on the right side. On the left side, the mean
distance was 10.28 mm with SD 5.24 mm and standard
error 0.98 mm. The analysis led to the acceptance of the
null hypothesis [Table 2].
Indian Journal of Dental Research, 26(6), 2015
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Sandhya, et al.
Localization of mandibular foramen in East Indian mandibles
The minimum, maximum, and mean distance of the MF
from the closest point of the superior border is detailed in
Table 3. This includes data from both the left and right side
of the mandible Table 3. Also includes the SD and standard
error for the dataset, as well as the t‑value and P value
for statistical analysis. It shows that the mean distance
between the MF and the superior border is 20.48 mm with
SD 3.89 mm, standard error 0.71 mm on the right side and
20.15 mm with SD 3.8 mm and standard error 0.71 mm on
the left side. The analysis led to the rejection of the null
hypothesis.
There may be bilateral symmetry for the distance between
superior border and MF as no evidence was found against
H0 at the 1% level of significance.
The minimum, maximum, and mean distance of the MF
from the closest point of the inferior border is detailed in
Table 4. This includes data from both the left and right side
of the mandible [Table 4]. Also includes the SD and standard
error for the dataset, as well as the t‑value and P value for
statistical analysis. It shows that the mean distance between
the MF and the inferior border is 24.15 mm with SD 4.97 mm
standard error 0.91 on the right side and 24.86 mm with SD
4.04 mm standard error 0.75 mm on the left side. Analysis
led to nonrejection of the null hypothesis.
There may be bilateral symmetry for the distance between
inferior border and MF as no evidence was found against
H0 at the 1% level of significance.
The minimum, maximum, and mean distance of the MF
from the closest point on the condyle is detailed in Table 5.
This includes data from both the left and right side of the
mandible. Table 5 also includes the SD and standard error for
the dataset, as well as the t‑value and P value for statistical
analysis. It shows that the mean distance between the
MF and the condyle is 33.46 mm with SD 6.08 mm and
standard error 1.1 mm on the right side and 32.48 mm with
SD 4.73 mm and standard error 0.86 mm on the left side.
Analysis of data reveals rejection of the null hypothesis at
1% level of significance.
There is no bilateral symmetry for the distance between
the condyle and MF.
The minimum, maximum, and mean distance of the MF
from the closest point of the internal oblique ridge is
detailed in Table 6. This includes data from both the left
and right side of the mandible. Table 6 also includes the
SD and standard error for the dataset, as well as the t‑value
and P value for statistical analysis. It shows that the mean
distance between the MF and the internal oblique ridge is
12.31 mm with SD 4.88 mm and standard error 0.9 mm on
the right side, whereas on the left side the mean distance was
Indian Journal of Dental Research, 26(6), 2015
Table 1: Distance between mandibular foramen and anterior
border (mm)
Side
Right
Left
t
P
Minimum
7.5
11
0.34
0.01
Maximum
21.5
22
Mean
16
16.27
SD
3.5
3.9
SE
0.64
0.73
SD=Standard deviation, SE=Standard error
Table 2: Distance between mandibular foramen and posterior
border (mm)
Side
Right
Left
t
P
Minimum
4
7
1.59
0.01
Maximum
14
15
Mean
10.21
10.28
SD
2.34
5.24
SE
0.43
0.98
SD=Standard deviation, SE=Standard error
Table 3: Distance between mandibular foramen and superior
border (mm)
Side
Right
Left
t
P
Minimum
15
13
0.41
0.01
Maximum
28
34
Mean
20.48
20.15
SD
3.89
3.8
SE
0.71
0.71
SD=Standard deviation, SE=Standard error
Table 4: Distance between mandibular foramen and inferior
border (mm)
Side
Right
Left
t
P
Minimum
12.5
16
1.82
0.01
Maximum
35
35
Mean
24.15
24.86
SD
4.97
4.04
SE
0.91
0.75
SD=Standard deviation, SE=Standard error
Table 5: Distance between mandibular foramen and
condyle (mm)
Side
Right
Left
t
P
Minimum
19
20
11.53
0.01
Maximum
39
40
Mean
33.46
32.48
SD
6.08
4.73
SE
1.1
0.86
SD=Standard deviation, SE=Standard error
Table 6: Distance between mandibular foramen and internal
oblique ridge (mm)
Side
Right
Left
t
P
Minimum
6
7
1.85
0.01
Maximum
18
19
Mean
12.31
10.93
SD
4.88
4.06
SE
0.90
0.94
SD=Standard deviation, SE=Standard error
32.48 mm with SD 4.73 mm and standard error 0.86 mm.
The analysis led to rejection of the Null hypothesis.
There may be bilateral symmetry for the distance between
internal oblique ridges to MF as no evidence was found
against H0 at 1% level of significance.
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Sandhya, et al.
Localization of mandibular foramen in East Indian mandibles
DISCUSSION
The present study is conducted on the mandibles of the
population of Jharkhand (East Zone) in India. The findings
of this study may be utilized by the dental surgeons in
assessing the position of the MF in the local population
while using the inferior alveolar block for local anesthesia.
In this study, it was found that the MF was situated at a mean
distance of 1.29 mm (right) and 1.78 mm (left) posterior
from the midpoint of the anteroposterior (AP) dimension
of ramus that is consistent with the findings of studies
carried out by Mbajiorgu,[11] Hetson et al.[14] and Hayward
et al.[15] Mbajiorgu[11] who worked on the Zimbabwean’s
sample, showed that the position of the MF was highly
individualistic, but on average lies at about 2.56 mm (right)
and 2.00 mm (left) behind the midpoint of ramus width.
Hetson et al.[14] stated that the MF was located immediately
posterior to the center of the ramus. Whereas Hayward et al.[15]
states that it is located in 3rd quadrant anteroposteriorly. In
this study, the mean distance of MF from the anterior border
of ramus was 16 mm on the right side and 16.27 mm on the
left side and that from posterior border was 10.21 mm and
10.28 mm on the right side and left side respectively, which
was very much similar with the findings of Hoque et al.[16]
in Bangladesh and Varma et al.[17] in South India. Hoque
et al.[16] conducted a study on Bangladeshi population and
reported that the mean distance of MF from anterior border
of ramus was 16.34 mm on the right side and 16.27 mm on
the left side. Varma et al.[17] found it as 16.52 mm on the right
side and 16.94 mm on the left side and a mean distance of
MF from posterior border 13.35 mm on the right side and
13.46 mm on the left side in the South Indian Mandibles.
Hayward[15] in their study stated that the mean size of the
anterior dimension was greater than the mean size of the
posterior dimension of the ramus in all instances; the MF was
found to be located in the third quadrant anteroposteriorly;
there was no right‑ or left‑side dominance in the ramus size
and position of the MF.
Thangavelu et al.[8] found in their study that the MF was
positioned at a mean distance of 19 mm (with SD 2.34 mm)
from the anterior border of the ramus. The variability of
distance from AB to MF was also not significant enough to
produce failure of anesthesia. If we compare our work with
some other ethnic groups, then we see that the distance of
the MF to the angle of the anterior ramus which were 16 mm
and 16.27 mm on the right and the left side, respectively in
our study, these were 16.9 mm on the right and 16.78 mm on
the left side in Turkish population as reported by Oguz and
Bozkir.[12] According to Lee[13] whose study was on Korean
samples, the MF was located posteriorly to the midpoint
of the AP width of the ramus. It was located at 57.3% of
the AP width of the anterior border. At the same scale, our
574
study showed MF to be located at 61.04% of the AP width
of the anterior border so here also our value differs that
found in Korean samples. In the vertical dimension, the
MF was found at a mean distance of 20.48 mm (right) and
20.15 mm (left) from the mandibular notch in our study. In
south India by Varma et al.[17] this distance was reported as
23.39 (right) and 24.41 (left) in dentulous and 21.65 (right)
20.92 (left) in edentulous sample. When it was taken in
reference to mid‑point of MF, then it was located 1.79 mm
(right) and 1.56 mm (left) superior to the midpoint. This
differed from studies carried out by Nicholson[18] according
to them the MF was predominantly located at the center of
the mandibular ramus. Our results were in accordance with
the results found by Williams et al.[19] study, and Oguz and
Bozkir.[12] According to Williams et al.[19] study the MF was
located above the center of the ramus on the medial surface.
At the same time, Oguz and Bozkir,[12] studied Turkish
sample and reported the distance of the lowest point of the
mandibular notch to the foramen was 22.37 mm on the right
and 22.17 mm on the left. The distance from the MF to the
inferior border of the ramus in the mid position of the ramus
was 30.97 mm on the right and 29.75 mm on the left side.
Again, while comparing with some other ethnic groups, we
notice that Mbajiorgu[11] reported MF to be approximately
3 mm superior to the midpoint of rameal height on both
sides in the Zimbabwean’s sample. Work done by Oguz
and Bozkir[12] on Turkish sample showed that the MF was
located superiorly to the midpoint on the vertical height of
the ramus, on the 48.5% of the vertical distance from the
coronoid notch.
The findings of a study conducted by Narayana et al.[20] study
indicated the bilateral symmetry of the MF by assessing
human dry mandibles; in our study also, there was no
significant difference between the right and left a side. He
further stated the MF was located above the center of the
ramus on the medial surface. In our study, a distance of MF
from condyle was 33.86 on the right side and 32.48 mm on
the left side which is quite different with the results found
by Thangavelu et al.[8] They reported that this distance as
38.14 mm on the right side and 37.60 mm on the left side.
However, our result showed significant bilateral asymmetry,
and this was consistent with the work done by Thangavelu
et al.[8]
Clinical implication
The dental surgeons can utilize this information during
the local anesthesia involving the inferior alveolar nerve
(IAN) for different procedures such as dental extraction,
placement of mandibular implants, and other therapeutic
procedures involving mandibles in the local population of
Jharkhand. Clinicians can also use internal oblique ridge
and temporomandibular joints (condyles), as a reference
point for planning different techniques of IAN block
(IANB).
Indian Journal of Dental Research, 26(6), 2015
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Sandhya, et al.
Localization of mandibular foramen in East Indian mandibles
CONCLUSION
Our study showed that the MF was located in the
posterosuperior quadrant of the ramus. On the right side,
it was located at a mean distance of 1.29 mm posterior to
the midpoint of the AP dimension and 1.79 mm superior
to the midpoint of vertical dimension. On the left side,
it was 1.78 mm posterior from the midpoint of the AP
dimension and 1.56 mm superior to the midpoint in the
vertical dimension. The dental surgeon can utilize this
information during the anesthetic procedures involving
the IAN. Clinicians can also use internal oblique ridge and
temporomandibular joints (condyle), as a reference point
for planning different techniques of IANB.
Acknowledgment
We would like to acknowledge the contribution made by
Dr. V. Dhar for helping us in selecting an appropriate statistical
tools and methods to analyze the data. Furthermore, we
would also like to acknowledge Mrs. Toshe for her continued
encouragement during the work and assistance in computer
application and Mr. Rataneswar Malik (Attendent) for his
assistance in handling the bones.
Financial support and sponsorship
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
Nil.
Conflicts of interest
There are no conflicts of interest.
REFERENCES
1.
2.
3.
Standring S, Ellis H, Healy J C, Johnson D, Williams A, Collins P, et al.
Grays Anatomy. 39th ed. Elsevier: Churchill Livingstone, London; 2005.
p. 482.
Heasman PA. Variation in the position of the inferior dental canal and
its significance to restorative dentistry. J Dent 1988;16:36‑9.
Bremer G. Measurements of special significance in connection with
Indian Journal of Dental Research, 26(6), 2015
16.
17.
18.
19.
20.
anesthesia of the inferior alveolar nerve. Oral Surg Oral Med Oral
Pathol 1952;5:966‑88.
Daw JL Jr., de la Paz MG, Han H, Aitken ME, Patel PK. The mandibular
foramen: An anatomic study and its relevance to the sagittal ramus
osteotomy. J Craniofac Surg 1999;10:475‑9.
Meechan JG. How to overcome failed local anaesthesia. Br Dent J
1999;186:15‑20.
Potocnik I, Bajrovic F. Failure of inferior alveolar nerve block in
endodontics. Endod Dent Traumatol 1999;15:247‑51.
Shah K, Shah P, Parmar A. Study of the location of the mandibular
foramina in Indian dry mandibles. Glob Res Anal 2013;2:128‑30.
Thangavelu K, Kannan R, Kumar NS, Rethish E, Sabitha S, Sayeeganesh N.
Significance of localization of mandibular foramen in an inferior
alveolar nerve block. J Nat Sci Biol Med 2012;3:156‑60.
Komar D, Lathrop S. Frequencies of morphological characteristics in
two contemporary forensic collections: Implications for identification.
J Forensic Sci 2006;51:974‑8.
Neiva RF, Gapski R, Wang HL. Morphometric analysis of implant‑related
anatomy in Caucasian skulls. J Periodontol 2004;75:1061‑7.
Mbajiorgu EF. A study of the position of the mandibular foramen in
adult black Zimbabwean mandibles. Cent Afr J Med 2000;46:184‑90.
Oguz O, Bozkir MG. Evaluation of location of mandibular and mental
foramina in dry, young, adult human male, dentulous mandibles. West
Indian Med J 2002;51:14‑6.
Lee SW, Jeong H, Seo YK, Jeon SK, Kim SY, Jang M, et al. A morphometric
study on the mandibular foramen and the lingula in Korean. Korean J
Phys Anthropol 2012;25:153‑66.
Hetson G, Share J, Frommer J, Kronman JH. Statistical evaluation of the
position of the mandibular foramen. Oral Surg Oral Med Oral Pathol
1988;65:32‑4.
Hayward J, Richardson ER, Malhotra SK. The mandibular foramen:
Its anteroposterior position. Oral Surg Oral Med Oral Pathol
1977;44:837‑43.
Hoque MM, Ara S, Begum S, Kamal AH, Momen MA. Study of
morphometric analysis of mandibular foramen in Bangladeshi dry
adult human mandible. Banglad J Anat 2013;11:58‑61.
Varma CL, Haq I, Rajeshwari T. Position of mandibular foramen in South
Indian mandibles. Anat Karnataka 2011;5:53‑6.
Nicholson ML. A study of the position of the mandibular foramen in
the adult human mandible. Anat Rec 1985;212:110‑2.
Williams PL, Bannister LH, Berry MM, Collins P, Dyson M, Dussek JE, et al.
Gray’s Anatomy. 38th ed. Elsevier: Churchill Livingstone, London; 2000.
p. 576‑7.
Narayana K, Soubhagya RN, Prashanthi N, Latha VP. The location of
the mandibular foramen maintains absolute bilateral symmetry in
mandibles of different age groups. Hong Kong Dent J 2005;2:35‑7.
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