Variations of fissures of lungs
Rev Arg de Anat Clin; 2012, 4 (2): 50-56
__________________________________________________________________________________________
Original communication
VARIATIONS OF FISSURES OF LUNGS
Anterpreet K Arora¹, Poonam Verma1, Jagdev Singh Kullar2, Ravi Kant Sharma2,
Rajan Singla2, Anupama Mahajan1
1
Department of Anatomy, Sri Guru Ram Das Institute of Medical Sciences and Research,
Amritsar. Punjab, India.
2
Department of Anatomy, Govt Medical College Amritsar. Punjab, India.
RESUMEN
ABSTRACT
Antecedentes: La conciencia y el conocimiento de las
variaciones anatómicas de las fisuras del pulmón es
requerido por los discípulos de especialidades
interesados para una interpretación precisa sobre
diferentes técnicas de imagen. Este conocimiento es
necesario para el reconocimiento de la anatomía
lobular y así localizar los segmentos broncopulmonar.
Por lo tanto, se realizó un estudio cadavérico que
informa la prevalencia de variaciones de número de
fisuras del pulmón en población Punjabi. Método: Las
cavidades torácicas de 50 cadáveres debidamente
embalsamados que contienen los pulmones fueron
disecados y se observaron las características
morfológicas de las variaciones anatómicas como
número, fisuras y los lóbulos. Resultados: Cien fisuras
pulmonares se observaron en 55 pulmones. Había
variaciones en 41 pulmones derecho y 14 pulmones
izquierdos. Cinco pulmones derechos mostraron
ausencia de fisura horizontal, un pulmón derecho no
tenía fisura, quince pulmones derechos mostraron
fisura horizontal incompleta. Once pulmones derechos
y seis pulmones izquierdos tuvieron fisuras oblicuas
incompletas. En cuatro pulmones izquierdos la fisura
oblicua estuvo ausente. Se observaron fisuras
supernumerarias en cuatro pulmones izquierdos y
nueve pulmones derechos. Las conclusiones: El
conocimiento anatómico de las variaciones de fisuras
y lóbulos puede ser importante, y también para
académicos en el campo médico. Las conclusiones
con respecto a las variaciones vistas en fisuras de
ambos los pulmones fueron comparables con estudios
anteriores. Las variaciones de anatomía pulmonar son
importantes para ambos: el diagnóstico por radiólogos
que interpretan radiografías y escáneres de tomografía
computada y el tratamiento de varias enfermedades
pulmones por cirujanos al realizar lobectomías y por
clínicos que implican todos los dominios de la
medicina.
Background: Awareness and knowledge of anatomical
variations of fissures of lung is required by the
disciples of concerned specialties for accurate
interpretation on different imaging techniques. This
knowledge is necessary for the appreciation of lobar
anatomy and thus locating the bronchopulmonary
segments. Therefore a cadaveric study was
undertaken to report the prevalence of variations
involving number of fissures of lung in Punjabi
population. Methods: The thoracic cavities of 50
properly embalmed cadavers containing lungs were
dissected and morphological features like number,
fissures and lobes were observed for the presence of
anatomical variations. Results: A total of 100 variant
pulmonary fissures appeared in 55 lungs. There were
variations in 41 right lungs and 14 left lungs. Five right
lungs showed the absence of horizontal fissure, one
right lung was without any fissure, fifteen right lungs
showed incomplete horizontal fissure. Eleven right
lungs and six left lungs had incomplete oblique
fissures. In four left lungs oblique fissure was absent.
Supernumerary fissure was seen in four left lungs and
nine right lungs. Conclusions: Anatomical knowledge
of variations of fissures and lobes may be important,
and also to academicians in the medical field. The
findings regarding the variations seen in fissures of
both the lungs were comparable with previous studies.
Variations of lung anatomy are important for both the
diagnosis by radiologists interpreting X-rays and CT
scans and treatment of various lungs diseases by
surgeons performing lobectomies and by clinicians
involving all the domains of medicine.
Palabras
clave:
Pulmones,
pulmonares, variación.
fisuras,
lóbulos
Key words:
variations.
Lungs,
fissures,
pulmonar
lobes,
_________________________________________________
* Correspondence to: Dr. Anterpreet Kaur Arora, 244,
Medical Enclave, Opposite Kahlon Diagnostics, Amritsar143001 Punjab, India. [email protected]
Received: 4 June, 2012. Revised: 28 June, 2012. Accepted:
6 July, 2012.
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Variations of fissures of lungs
Rev Arg de Anat Clin; 2012, 4 (2): 50-56
__________________________________________________________________________________________
Figure 1.- A) Left lung with supernumerary fissure on diaphragmatic surface. B) Right lung with incomplete horizontal
fissure and complete oblique fissure
INTRODUCTION
Conventionally, according to the text books of
Anatomy, the left lung is divided into two lobes by
a deep oblique fissure and the right lung has two
fissures, an oblique and a horizontal dividing it
into three lobes namely the superior, middle and
lower lobes (Figure 1B). The oblique fissure runs
downwards, thereby meeting the inferior border
of the lung at a distance of approximately 7.5 cm
behind anterior end (Standring, 2005). During the
development, as the lung grows, the fissures that
separate individual bronchopulmonary buds or
segments become obliterated except along two
planes which form oblique or horizontal fissures
in the fully developed lungs. Supernumerary
fissures (Figures 2C, 2E, 1A) could be the result
of non-obliteration of fissures which normally are
obliterated (Larsen et al, 1993). The supernumerary fissure may be of varying depth
occurring between bronchopulmonary segments.
Absence or incomplete oblique or horizontal
fissure could be due to obliteration of these
fissures either completely or partially (Figures
3G, 3H, 3I, 3J). The fissures may vary in the
degree of completeness and tend to divide the
lobe into smaller subdivisions. Complete fissures
show continuity of lobes at their bottom only by
the parts of bronchial tree and blood vessels. In
the region of incomplete fissures the adjacent
lobes are connected by a sizeable chunk of
pulmonary tissue as the cleft fails to reach the
hilum. The fissure may be absent altogether
(Figures 2F, 3J). The fissures are conducive to
uniform expansion of lobes. They provide routes
for movements of lobes in relation to each other.
This is more relevant to distension and
movement of the lower lobes during breathing
(Rosse et al, 1997).
The position of fissure could be used as reliable
landmark in specifying lesions within the thorax,
in general and within the lungs in particular (Kent
et al, 1942). Sometimes especially in infant,
supernumerary fissures of varying depth can be
seen in unusual locations of the lung delimiting
abnormal lobes which correspond to the normal
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Variations of fissures of lungs
Rev Arg de Anat Clin; 2012, 4 (2): 50-56
__________________________________________________________________________________________
bronchopulmonary segments (Rosse et al, 1997).
Radiologically, an supernumerary or variant
fissure is important as it can be mistaken for a
lung lesion (Aldur et al, 1997). The
supernumerary fissure might act a barrier to
spread in the tissue creating a sharply
demarcated pneumonia, which could be
misinterpreted as an atelectasis or consolidation
(Nene et al, 2010). Segmental localisation is
must for a thoracic surgeon and knowledge of
supernumerary fissure is a great significance to
cardio thoracic surgeon for planning segmental
resections or pulmonary lobectomy. In the
present case observation of a transverse fissure
only on the medial side of left lung is of great
clinical and surgical importance, since it may be
presumed as an independent lobe. Considering
all the above facts the knowledge of fissure
comes to bear greater role for clinicians,
surgeons as well as radiologists. (Devi et al,
2011)
Figure 2.- C) Left lung showing supernumerary fissure at anterior border. D) Right lung with one oblique fissure. E)
Right lung showing supernumerary fissure at base of lung. F) Right lung with no fissure
52
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Variations of fissures of lungs
Rev Arg de Anat Clin; 2012, 4 (2): 50-56
__________________________________________________________________________________________
Figure 3.- G) Right lung with both the fissures incomplete and horizontal fissure not meeting oblique fissure. H) Left lung
with incomplete oblique fissure. I) Left lung with incomplete oblique fissure. J) Left lung with no fissure.
.
MATERIAL AND METHODS
Fifty pairs of lungs from equal number of both the
sexes, formalin-fixed Punjabi cadavers were
used for this study. Details of fissures complete,
incomplete or absent; presence of any variant
fissure, supernumerary fissures were recorded.
The specimens were photographed and the
records were compared with previous data. The
anatomical classification proposed by Craig and
Walker was followed to determine for the
presence and completeness of fissures (Craig et
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Variations of fissures of lungs
Rev Arg de Anat Clin; 2012, 4 (2): 50-56
__________________________________________________________________________________________
al, 1997). Craig and Walker have proposed a
fissural classification based on both the degree of
completeness of the fissures and the location of
the pulmonary artery at the base of the oblique
fissure. Four stages have been described: Grade
I- complete fissure with entirely separate lobes;
Absence
Incomplete
of right
Left
Horizont
oblique
Oblique
al
fissure
T
Incomp
Incomplete
Absent
y
lete
Right
Right
p
Right
Oblique
e
Horizo
ntal
Fisssure
1
Absent Left
Oblique
Fissure
Grade-II- complete visceral cleft but parenchymal
fusion at
the base of the fissure; Grade III- visceral cleft
evident for a part of the fissure; and Grade IVcomplete fusion of lobes with no evident fissural
line.
27.2%
20.0%
11.0%
(Fig.
(Fig. 3G)
(Fig. 3H)
Supernu
merary
fissures
Right
Lung
Supernu
merary
fissures
Left Lung
Comp
lete
absen
ce of
fissue
s in
right
Lung
Comp
lete
absen
ce of
fissur
e in
left
lung
1.8%
(Fig.2
F)
7.3%
(Fig.3
J)
1B, 3G)
2
9.0%
7.3% (Fig.
(Fig. 2D)
3J)
0%
3
16.4%
(Fig. 2E)
7.3%
(Fig. 1A,
2C)
Table 1.- Types of variations of pulmonary fissures in the present study.
RESULTS
Variations of pulmonary fissures appeared in 55
(55%), among them, 41 cases (74.6%) were right
variations while 14 cases (25.4%) were left
variations. Three types of variations were
observed (Table 1):
Type 1: There were Incomplete Right Horizontal
fissures (Figure 1B and 3G), Incomplete Right
Oblique fissures (Figure 3G) and Incomplete Left
Oblique fissures (Figure 3H).
Type 2: There was Absent Right Horizontal
Fissure (Figure 2D), Absent Left Oblique Fissure
(Figure 3J), Complete absence of fissures in right
Lung (Figure 2F) and Complete absence of
fissure in left lung (Figure 3J).
Type 3: There were Supernumerary fissures
Right Lung (Fig. 2E),
Complete absence of
fissure in left lung (Fig. 1A, 2C).
DISCUSSION
Incomplete pulmonary fissures indicating partial
fusion between lobes are most common. In a
radiological study, the inferior supernumerary
fissure which demarcates the medial basal
segment, and superior fissure which demarcates
the superior segment, was the most common
supernumerary fissure detected on CT scan
(Tarver et al, 1995). Several authors have
reported varying percentages of incidence of the
incompleteness and absence of the fissures
(Table 2). (Medlar et al, 1947, Raasch et al,
1982, Kent et al, 1942, Bergman et al, 2002)
When compared with the study reported by
Medlar (Medlar et al, 1947), the incidence of
incomplete fissure (Figures 1B, 3G 3H and 3I)
was higher and the incidence of absence of
horizontal fissure (Figures 2D, 2F) was lower in
the present study whereas incidence of absence
of oblique fissure (Figure 3J) in left lung was in
accordance. In the study of Lukose et al
incomplete and absent horizontal fissure were
reported in 21%, and 10.5%, respectively. When
compared with the study by (Lukose et al, 1999)
incidences of a few variations observed were not
in accordance with the present study. Prevalence
of incomplete oblique fissure of left lung (Figures
3H, 3I) was lower in our work, where as it was
more prevalent in both the lungs in the study of
Prakash et al (2010) (Table 2). The nature of
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Variations of fissures of lungs
Rev Arg de Anat Clin; 2012, 4 (2): 50-56
__________________________________________________________________________________________
fissure is of great importance in planning
operative strategy for thoracoscopic pulmonary
resection where an incomplete fissure may
contribute to post-operative air leakage. In order
to provide a frame work for description of
operative technique and to allow meaningful
comparison between different surgical series,
When compared with the studies by (Bergman et
S
no
al, 2002; Meenakshi et al, 2004), a lower
incidence of variations was observed in all the
parameters taken in the present study. In the
study of Nene et al (2011) incomplete (Figures
1B, 3G) and absent horizontal fissure (Figure 2D,
2F) was reported in 8% and 14% in right lung and
absent oblique fissure in none of the left lungs.
Fissures of Right lung
Fissures of Left lung
Authors & Year
Horizontal
Oblique
Supernumer
Oblique
Supernumer
ary
Absent
ary
Incompl
Absen
Incompl
Absen
Incompl
ete
t
ete
t
ete
4.8%
25.6%
---
7.3%
10.6%
1
Medlar, 1947
45.2%
17%
---
2
Lukose et al., 1999
10.5%
21%
--
--
….
0
21%
---
3
IEHAV7 (2002)
21%
67%
-
30%
--
--
30%
---
4
Meenakshi et al.,
16.6%
63.3%
--
36.6%
---
-
46.6%
--
21%
67%
---
30%
--
--
30%
--
2004
5
Bergman et al.,
2008
6
Prakash et al., 2010
7.1
50
7.1
39.3
35
10.7
35.7%
---
7
Nene et al., 2011
14%
8%
2%
6%
18%
0
12%
50%
8
Present study, 2012
9.0.%
27.2%
0%
20.0%
16.4%
7.3%
11%
(Figure
(Figures
(Figure
(Figure 2E)
(Figur
Figures
(Figures 1A,
s 2D,
1B, 3G)
3G)
e 3J)
3H, 3I)
2C)
7.3%
2F)
Table 2.- Comparison of the present study with the studies reported by other scientists
Knowledge of such variations might explain
bizarre presentation of certain clinical cases
pertaining to lung pathologies. Also knowing the
frequency of occurrence of a variant fissure in a
particular population might help the radiologist
and clinician to make correct diagnosis, plan,
execute and modify a surgical procedure
depending on the merit of the case (Nene et al,
2011).
The results of present study and their comparison
with the previous works show that there is a wide
range of difference in occurrence of major, minor
and supernumerary fissures between and among
different populations. This implies that a variety of
genetic and environmental factors might affect
development of these fissures. Recognition of the
supernumerary fissures provides additional
information in segmental localization of
pulmonary lesions and assists in differential
diagnosis of supernumerary fissures from normal
anatomical and pathological structures. Being
aware of these variations before a thoracic
procedure may sometimes facilitate surgery.
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