International Journal of Anatomical Sciences 2011, 2(2):31-33

Case Report

Incomplete Horizontal Fissure of Right Lung – A Case Report

Kirubhanand C, Tamilselvi P, Sridhar Skylab R, Sankar V.

Department of Anatomy, Dr.A.L.M.Postgraduate Institute of Basic Medical Sciences, University of Madras, Taramani Campus, Chennai 600 113, Tamilnadu, India

 Abstract: The right lung has two fissures, an oblique and a horizontal, dividing it into three lobes namely the upper, middle and lower. The anomaly of the fissure pattern has been described by many radiologist, whereas, there were only fewer studies on gross anatomical specimens. The present case describes a peculiar incomplete horizontal fissure which started from the oblique fissure but did not traversed backwards  towards  the  medial  surface  of  the  lung.  Anatomical  knowledge  of anomalies of fissures and lobes of lungs is important for surgeons performing lobectomies,  radiologists  interpreting  X-ray  and  CT  scans  and  also  of  academic interest to all medical personnel.

 Key words: anatomical variation, abnormal lung fissure

The right lung normally has three lobes namely the upper, middle and lower formed by two  fissures;  an  oblique and  a horizontal   one   (Standring,   2005).   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).  The horizontal fissure passes from the oblique fissure at the level of midaxillary line to the anterior border of the lung at the level of sternal end of fourth costal cartilage (Standring 2005). In the present case we report an incomplete horizontal fissure in the right lung specimen for its rarity and academic interest.

 Case Report

During routine dissection training for postgraduate  students,  in  a  55  year  old female    cadaver,    we    encountered     an

Correspondence to: Sankar V, Department of Anatomy, Dr. ALM PGIBMS, University of Madras, Taramani Campus, Chennai  600113,Tamilnadu, India.Email:

Accepted: 15-Sep-2011

anomalous right lung, which displayed incomplete  horizontal  fissure.  The pulmonary fissures and lobes were studied and  appropriate measurements  were taken. The specimen was photographed.

 The right lung displayed an oblique fissure,  which  originated  at  a  distance  of  7cm from the apex on the vertebral part of medial   surface   and   after   traversing   a distance of 8 cm, it continued downwards as the conventional oblique fissure to cross the inferior border at a distance of 2 cm. Thus the oblique fissure was as per standard descriptions. Although the horizontal fissure was  seen  as  per  typical  description  i.e.  it runs from oblique fissure 10 cm from the anterior border, it did not traverse backwards towards  the  medial  surface  of  the  lung. Thus, instead of traversing the entire lung, the horizontal fissure seen in this specimen did not divide the lung completely into a middle lobe. As a consequence to such anomalous incomplete horizontal fissure, the right lung was found to possess a completely divided lower lobe with upper and middle lobes   incompletely   separated   from   each other. No abnormality was detected in the left lung.

 Fig. 1 Photograph showing the right lung seen with an incomplete horizontal fissure











 Fig. 2 Diagrammatic representation of fissure pattern of normal right lung and the anomalous one reported


 Lung develops from numerous bronchopulmonary buds which fuse completely in the later part of development  except at sites of fissure formation, resulting in the formation of lobes and fissures (Frija et al., 1988). Any deviation from the normal pathway  of  fusion  of  bronchopulmonary buds results in the formation of variations involving lobes and fissures of the lungs (Sadler, 2004). The fissures are the spaces which separate individual bronchopul- monary buds or segments and they get obliterated  except  along  the  two  planes which   later   manifests   as   horizontal   or oblique fissure Non-obliteration of these spaces gives rise to accessory issures of the lung (Meenakshi, 2004).

 An incomplete fissure may be of varying depth occurring between bronco- pulmonary segments and is also a cause for post operative air leakage (Walker, 1997). Often accessory fissures  act  as  barriers  to infection  spread,  creating  a  sharply marinated pneumonia which can wrongly be interpreted as atelectasis or consolidation (Godwin and Tarver, 1984). The knowledge of anatomy of fissures of lung may help clarifying initially confusing radiographic findings like extension of fluid into an incomplete   major   fissure   or   spread   of various diseases through different pathways (Dandy, 1978) and explain radiological appearances   of   interlobar   fluid   (Raasch,1982). Accurate recognition of lung anomalies in different populations will improve the understanding of lesions like pneumonia, pleural effusion, and collateral air   drift   along   with   disease   spreading through the lung.

 Aldur et al., (1997) concluded that a surgeon must always remember the anatomical variations of the location of the lungs especially in lobectomies and in segmental resection. Hayashi et al., (2001) concluded that anatomy of normal variants of the major fissures is essential for recognizing their variable imaging appearances and related abnormalities.

The   presence   of   fissures   in   the normal  lungs  enhances  uniform  expansion

Kirubhanand et al., – Incomplete horizontal fissue of right lung    and hence facilitates more air intake. Accessory  and  incomplete  fissures  of varying   depth   can   be   seen   in   unusual   Standring S  (2005)  Gray’s  Anatomy. 39th New York: Churchill Livingstone,.

Edition.locations  of the lung,  delimiting abnormal lobes which corresponding to the normal bronchopulmonary segments especially in infants. From a radiological point of view, an accessory or anomalous fissure is important as it can be mistaken for a lung lesion or an atypical appearance of pleural effusion.

 Considering the clinical and surgical importance of such variations, from anatomical point of view, one can opine that prior anatomical knowledge and high index of suspicion for probable variations in the fissures, lobes and bronchopulmonary segments in the lung may be important for clinicians, surgeons and radiologists.


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