The size and morphology of sella turcica: A lateral cephalometric study

Abstract

Background: Sella turcica is a saddle-shaped concavity in the body of sphenoid bone situated in the middle cranial fossa of skull, clearly seen on lateral cephalometric radiograph. Aim: The purpose of the study was to measure the size and describe the morphology of sella turcica in different age groups and gender. Materials and Methods: Lateral cephalometric radiographs of 200 subjects of which 100 males and 100 females in the age group of 8-30 years were included in the study population. Linear dimensions which include the length, depth, and anteroposterior diameter were measured and the shape of sella turcica was analyzed and skeletal class of malocclusion was noted. Chi-square test and ANOVA test were used for statistical analysis. Results: In the present study, morphology of sella turcica appeared to be normal shape (upper contour of anterior wall of sella turcica appears to be perpendicular to floor) in 46.5% of the study population and morphological variations in shape were seen in 53.5% of study population. Whereas size was considered there was statistically significant increase in the depth and anteroposterior diameter of sella turcica as age advanced. There was no significant difference in the linear measurements of sella turcica between males and females. Conclusion: The most common shape of sella turcica in the study population was normal shape. There is a gradual increase in the size of sella turcica as age advances.

Full text

Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:3 ● May-Jun 2015 3
Journal of Medicine, Radiology, Pathology & Surgery (2015), 1, 3–7
ORIGINAL ARTICLE
The size and morphology of sella turcica: Alateral
cephalometric study
Tejavathi Nagaraj1, R. Shruthi2, Leena James3, I. Keerthi2, Lakshmi Balraj2, Rahul Dev Goswami2
1Professor and Head, Department of Oral Medicine and Radiology, Sri Rajiv Gandhi College of Dental Sciences & Hospital, Bengaluru, Karnataka, India,
2Post‑graduate Student, Department of Oral Medicine and Radiology, Sri Rajiv Gandhi College of Dental Sciences & Hospital, Bengaluru, Karnataka, India,
3Professor, Department of Oral Medicine and Radiology, Sri Rajiv Gandhi College of Dental Sciences & Hospital, Bengaluru, Karnataka, India
Abstract
Background: Sella turcica is a saddle-shaped concavity in the body of sphenoid bone
situated in the middle cranial fossa of skull, clearly seen on lateral cephalometric radiograph.
Aim: The purpose of the study was to measure the size and describe the morphology of
sella turcica in dierent age groups and gender.
Materials and Methods: Lateral cephalometric radiographs of 200 subjects of which
100 males and 100 females in the age group of 8-30 years were included in the study
population. Linear dimensions which include the length, depth, and anteroposterior
diameter were measured and the shape of sella turcica was analyzed and skeletal class of
malocclusion was noted. Chi-square test and ANOVA test were used for statistical analysis.
Results: In the present study, morphology of sella turcica appeared to be normal shape
(upper contour of anterior wall of sella turcica appears to be perpendicular to oor)
in 46.5% of the study population and morphological variations in shape were seen in
53.5% of study population. Whereas size was considered there was statistically signicant
increase in the depth and anteroposterior diameter of sella turcica as age advanced.
There was no signicant dierence in the linear measurements of sella turcica between
males and females.
Conclusion: The most common shape of sella turcica in the study population was
normal shape. There is a gradual increase in the size of sella turcica as age advances.
Keywords
Lateral cephalogram, sella turcica, sella turcica
morphology and size
Correspondence:
Dr.R. Shruthi, Department of Oral
Medicine and Radiology, Sri Rajiv
Gandhi Dental College and Hospital,
Cholanagar, Bengaluru-560032,
Karnataka, India. Phone:+91-9686666902,
Email: drshruthir@gmail.com
Received 15 February 2015;
Accepted 28 March 2015
doi: 10.15713/ins.jmrps.14
Introduction
Sella turcica is a saddle-shaped concavity in the body of sphenoid
bone situated in the middle cranial fossa of the skull. Sella turcica
gets its name from Turkish language because of its similarity to
the Turkish saddle. The depression in saddle is noted as pituitary
fossa or hypophyseal fossa. The pituitary gland is situated in
the hypophyseal fossa. It is limited by bony constituents of the
sella turcica, anteriorly by tuberculum sellae, posteriorly by
dorsum sellae and inferiorly by the bony roof of sphenoid air
sinus.[1,2] Sella turcica on lateral cephalometric radiograph can be
observed clearly and consecutively traced during cephalometric
analysis.[3] A larger size may be an indication of pituitary tumor
over producing hormones such as an adrenocorticotropic
hormone, prolactin, growth hormone, thyroid stimulating
hormone, antidiuretic hormone. The enlarged sella turcica on
a radiograph has been found to be associated with adenomas,
meningioma, primary hypothyroidism, prolactinoma, gigantism,
acromegaly, empty Sella syndrome, and Nelson syndrome.
A small size may lead to decreased pituitary function causing
symptoms such as short stature and retarded skeletal growth.[4]
Research concerning the sella turcica has focused on both size
and morphology. A normal morphological variation of sella
turcica vary greatly from individual to individual.[5] The aim
of this study was to determine the average dimensions and
morphological variations of the sella turcica in dierent age
groups and to evaluate any dierence in size between males and
females in the study population.
Materials and Methods
This radiographic study was conducted during a time period
of 6 months, from July 2014 to December 2014. The study
included a total of 200 digital lateral cephalometric radiographs
of 100 males and 100 females (between 8 and 30 years of age)

Size and morphology of sella turcica Nagaraj, et al.
4 Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:3 ● May-Jun 2015
who attended the Department of Oral Medicine and Radiology
and were grouped into ve categories based on age i.e., <10 years,
10-15 years, 15-20 years, 20-25 years, 25-30 years.
Inclusion criteria
a. Healthy patients without any history of systemic diseases
b. Patients in the age group of 8-30 years
c. Patients advised for lateral cephalometric radiographs for
orthodontic treatment.
Exclusion criteria
a. Individuals with congenital defects in the craniofacial region
like clefts and malformations
b. History of craniofacial fractures
c. Patients suering from disorders of bone, nutritional
deciencies and endocrinal disturbances.
Digital lateral cephalometric radiographs were taken by using
ORTHOPHOS XG machine with a tube voltage of 73 kV, tube
current of 15 mA and exposure time of 9.4 s. The distances were
measured using Sidexis Programs (Sirona) software. The length
was measured as the linear distance from the superior most
point on the tuberculum sella to the tip of the dorsum sella. The
depth was measured as a line perpendicular from the line joining
tuberculum sella and dorsum sella to the inferior most point
on the oor. The anteroposterior diameter of sella turcica is
measured from the superior most point on tuberculum sella to the
furthest point on the posteroinferior aspect of the hypophyseal
fossa [Figure 1]. Based upon the ANB angle, subjects were
classied into Class I, II, and III. ANB angle of ± 2° belongs
to Class I skeletal base. ANB angle of >4° belongs to Class II
skeletal base. ANB angle of <0° belongs to Class III skeletal
base. Shape and morphological appearance of sella turcica were
assessed according to the method described by Axelsson et al.
According to Axelsson et al., the ve morphological variations
are oblique anterior wall, bridging of sella turcica, double
contour of the oor, irregular surface (notch like depression) in
the posterior aspect of the dorsum sella, and pyramid shape of
dorsal sellae [Figure 2].[6]
Statistical analysis
The following methods of statistical analysis have been
used in this study. Data were entered in Microsoft excel and
analyzed using SPSS (Statistical Package for Social Science,
Ver.10.0.5) package. Univariate analyses of the dichotomous
variables encoded were performed by means of the Chi-square
test and were used to calculate the mean dierences in linear
measurements of sella turcica between males and females.
One‑way analyses of variance were used to test the dierence
between dierent age groups. To nd out which of the two
groups means is signicantly dierence post-hoc test of Schi’s
test was used. P < 0.05 was considered statistically signicant.
Results
The mean age of study population was 16.8 years, minimum
age was 8 years and maximum age was 30 years. Majority of the
study group had skeletal Class I malocclusion of 77.5%, skeletal
Class II and skeletal Class III were 17.5% and 5%, respectively.
The dierent morphological shape of sella turcica seen are
normal (upper contour of anterior wall of sella turcica appears to
be perpendicular to oor) 46.5%, followed by oblique anterior
wall 29%, sella turcica bridge 7.5%, double contour of oor
3.5%, irregular dorsum sella 7%, pyramidal shape 6.5%. The least
common type of sella turcica in study population found to be
double contour of the oor of 3.5% and most common type was
normal type of 46.5%.
The linear dimensions of sella turcica in dierent age group
are given in Table 1. The patients were grouped into ve dierent
categories, <10 years, 10‑15 years, 15‑20 years, 20‑25 years,
25‑30 years. There was dierence in the linear measurements
of depth, and anteroposterior diameter in each age group which
increased as age increased and the dierence was statistically
signicant with P < 0.05. The dierence in the length of dierent
age groups was not signicant.
The linear dimension of sella turcica among males and females
are given in the Table 2 where there was no statistically signicant
dierence in the size of sella turcica between males and females.
The distribution of dierent shapes of sella turcica among males
and females are given in Graph 1. The normal shape of sella turcica
was seen more commonly in females. Irregular dorsum sella was
more common in females and other morphological variations
were more commonly seen in males. There was no signicant
dierence in size between skeletal Class I, II, and III malocclusion.
Discussion
This study describes the morphological variations in structure
and size of the sella turcica of both genders under a wide range
of age group.
Figure 1: Linear measurements of sella turcica. L-Length, D-Depth,
APD-Anteroposterior diameter

Nagaraj, et al. Size and morphology of sella turcica
Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:3 ● May-Jun 2015 5
anterior wall, bridging of sella turcica, double contour of the
oor, irregular surface (notch like depression) in the posterior
aspect of the dorsum sellae, pyramid-like shape of the dorsum
sellae were recognized.[6]
Alkode conducted a study to evaluate the morphological
shapes of sella turcica in cleft lip and palate patients in 2008,
according to study he arrived at result majority of cleft subjects
had morphological aberrations such as a double contour of the
oor, an irregular posterior wall found more commonly than the
normally shaped sella turcica. Contrary to individuals with clefts,
in most non-cleft subjects the morphology of the sella turcica
appears to be normal.[7]
The morphological variations of sella turcica with greater
severity are more commonly seen in syndromic patients such as
Down’s syndrome, William’s syndrome, Seckel syndrome, and
Axenfeld-Rieger syndrome.[8-11]
A study was done by Sathyanarayana et al. in 2012 to assess the
size and morphology of sella turcica in south Indian population
having Class I, Class II, and Class III skeletal patterns. In this
study, 61% of the subjects had normal morphology whereas the
remaining 39% had variations in the shape, lowest being oblique
anterior wall in 5%, double contour of the oor in 5.5%, pyramid‑
like shape of the dorsum sellae in 5.5%, bridging of sella turcica in
8% of subjects, irregularity (notch like depression) in the posterior
surface of the dorsum sellae in 15% of study population.[12]
In contrast to above, study done by Chauhan et al. in 2014
showed morphology of sella turcica to be typical in just 28% of
cases. Within the atypical sellae most had oblique anterior wall
Shape of sella turcica
Gorden and Bell in 1922 examined radiographs of normal
children in between 1 and 12 years of age and categorized sella
turcica into three shapes, circular, oval, at/saucer shaped.
Circular or oval shaped sella turcica were observed in majority of
subjects, and they arrived at a conclusion that not all cases could
easily be put into such a broad three‑way classication.[5]
Axelsson et al. conducted a study in Norway using lateral
cephalometric radiographs of males and females in age range
of 6-21 year in 2004 to determine variations in size and shape
of sella turcica. The sella turcica morphology was analyzed and
ve types of dierent morphological aberration like oblique
Figure 2: Dierent morphological shapes of sella turcica: (a) Normal, (b) Oblique anterior wall, (c) sella turcica bridging, (d) double contour
of oor, (e) irregular dorsum sella, (f) pyramidal shape
d
c
f
a
e
b
Graph 1: Distribution of dierent shapes of sella turcica among
genders

Size and morphology of sella turcica Nagaraj, et al.
6 Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:3 ● May-Jun 2015
(23%), followed by irregular sellae (18%) bridging in 17% of
cases, double contour of oor 10%. None of the sella was seen
to be pyramidal in type in north Indian population.[13] In the
current study, the normal type of sella turcica is 46.5% of the
study population, morphological variations were 53.5%.
The presence of a sella turcica bridge in normal individuals
has been shown to occur in 5.5-22% of subjects, with an increased
incidence in patients with craniofacial deviations.[14-16] Najim
and Al-Nakib conducted a cephalometric study in 2011 to assess
morphology of sella turcica in patients with maxillary malposed
canine and normal population and found that prevalence of
sella turcica bridging was comparatively greater in subjects with
abnormally placed canine as compared to control group.[17] In
our study, 7.5% of the population had bridging of sella turcica.
Size of sella turcica
Tetradis and Kantor conducted a study in 1999 with sample of
325 orthodontic patients in which 134 patients were males and
191 were female patients, varying from 6 to 49 years with mean
age of 14.8 years. They measured linear dimensions of sella
turcica on the lateral cephalogram, the anteroposterior diameter
ranged from 6.0 to 17.0 mm, mean value was found to be 10.9 ±
1.8 mm, while the depth varied from 2.5 to 12.5 mm with a mean
of 7.6 ± 1.7 mm.[18]
The size of sella turcica was studied by Axelsson et al.
in a Norwegian sample longitudinally between the ages of
6 and 21 years. His study results found that the length was
almost constant throughout the observation period whereas
the depth and diameter increased with age.[6] Similarly,
statistically signicant values (P < 0.05) were derived from
present study where the depth and anteroposterior diameter
gradually increased with age, and regarding length there is no
signicant increase with age. The average length, depth, and
anteroposterior diameter ranged as 10 ± 5 mm, 8 ± 3 mm, 12 ±
4 mm, respectively. Based on the above result, growth of the
individual can be assessed based on the size of the sella turcica at
dierent age periods.
Study done by Axelsson et al. also revealed that there was
signicant dierence in the length of sella turcica in gender
which was more in males compared to females, whereas there is
no dierence in depth and anteroposterior diameter.[6] Similar
results were given in the study done in south Indian population
which showed the dierence in length of sella turcica between
males and females.[12]
In the present study, there was no signicant dierence in all
three dimensions in males and females. This result is correlating
with studies done by Yassir et al. 2010 in Iraq population,
Shah et al. 2011 in Pakistan population, Chavan et al. 2012 in
Maharashtra population, Osunwoke et al. 2014 in Nigerian
population, where between genders no signicant dierence was
found in terms of length, depth, and diameter.[5,19-21]
Conclusion
The most common morphological shape of sella turcica was
normal shape of about 46.5%. There was a signicant increase
in the depth and anteroposterior diameter of sella turcica as age
increases. There was no dierence in the size of sella turcica
between males and females. Normal shape of sella turcica was
Table1: Age-wise distribution of sella turcica parameters
Parameters NMean SD Minimum Maximum F value P value
Length
≤10years 13 9.12 1.464 7.07 13.00 0.638 0.636
11-15years 93 9.45 1.716 5.93 14.83
16-20years 39 9.86 1.945 5.62 14.91
21-25years 39 9.39 1.586 6.76 12.07
26-30years 16 9.67 2.216 5.26 15.32
Tot a l 200 9.52 1.762 5.26 15.32
Depth
≤10years 13 7.65 1.238 5.47 10.81 3.919 0.004
11-15years 93 7.94 1.545 4.37 13.69
16-20years 39 8.31 1.470 5.66 11.73
21-25years 39 8.53 1.312 6.03 11.65
26-30years 16 9.26 1.160 6.34 10.62
Tot a l 200 8.21 1.484 4.37 13.69
Diameter
≤10years 13 11.19 1.171 9.61 13.31 7.899 <0.001
11-15years 93 11.26 1.703 6.03 15.64
16-20years 39 11.93 2.000 4.32 15.55
21-25years 39 12.84 1.679 9.34 15.98
26-30years 16 12.92 1.669 9.74 17.23
Tot a l 200 11.83 1.847 4.32 17.23
N: Number of cases, SD: Standard deviation, P<0.05 significant, P>0.05 not
significant
Table2: Linear measurements of sella turcica size in both gender
Measurements NMean SD Minimum Maximum F value P value
Length
Male 100 9.69 1.907 5.26 15.32 2.047 0.154
Female 100 9.34 1.593 5.93 14.83
Tot a l 200 9.52 1.762 5.26 15.32
Depth
Male 100 8.34 1.488 4.37 13.69 1.412 0.236
Female 100 8.09 1.477 5.30 11.69
Tot a l 200 8.21 1.484 4.37 13.69
Diameter
Male 100 11.59 2.006 4.32 17.23 3.478 0.064
Female 100 12.07 1.648 6.03 15.98
Tot a l 200 11.83 1.847 4.32 17.23
N: Number of cases, SD: Standard deviation

Nagaraj, et al. Size and morphology of sella turcica
Journal of Medicine, Radiology, Pathology & Surgery ● Vol. 1:3 ● May-Jun 2015 7
seen more commonly in females than males. The results can be
used as a reference in future studies with larger study population.
Clinical signicance
The normal anatomy and variations in the morphology and size
of sella turcica on a lateral cephalometric radiograph should be
acquainted by clinicians, in order to analyze deviations that may
reect pathological situations. Growth of the individual can be
assessed based on the size of the sella turcica at dierent age
period.
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How to cite this article: Nagaraj T, Shruthi R, James L,
Keerthi I, Balraj L, Goswami RD. The size and morphology of
sella turcica: A lateral cephalometric study. J Med Radiol Pathol
Surg 2015;1:3-7.