Radiographic and CT Appearances of the Major Fissures1
Kuniaki Hayashi, MD,
Aamer Aziz, MD,
Kazuto Ashizawa, MD,
Hideyuki Hayashi, MD,
Kenji Nagaoki, MD and
Hideaki Otsuji, MD
1 From the Department of Radiology, Nagasaki University School of Medicine, Sakamoto 1-7-1, Nagasaki 852-8501, Japan (K.H., A.A., K.A., H.H., K.N.); and the Department of Radiology, Saiseikai Suita Hospital, Osaka, Japan (H.O.). Recipient of an Excellence in Design award for a scientific exhibit at the 1999 RSNA scientific assembly. Received February 6, 2001; revision requested March 7 and received April 24; accepted April 25. Address correspondence to K.H. (e-mail: hayashik@net.nagasaki-u.ac.jp).
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Figure 1. Drawing illustrates the propeller-like configuration of the major fissures.
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Figure 2. Normal major fissures. Lateral chest radiograph demonstrates the two major fissures. Note that both fissures are seen as double lines and that the left fissure (arrows) is behind the right fissure (arrowheads).
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Figure 3. Normal major fissures. CT scan shows the major fissures as lucent bands of relative hypovascularity (arrows).
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Figure 4. Normal major fissures. CT scan shows the major fissures as dense bands (arrows).
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Figure 5a. Normal major fissures. High-resolution CT scans (b obtained at a lower level than a) show the major fissures as lines (arrows). Note that their orientation changes as they pass from superior to inferior.
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Figure 5b. Normal major fissures. High-resolution CT scans (b obtained at a lower level than a) show the major fissures as lines (arrows). Note that their orientation changes as they pass from superior to inferior.
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Figure 6a. Superolateral major fissures. (a) Posteroanterior radiograph shows the superolateral major fissures as curving contours with lateral opacity and medial lucency bilaterally (arrows). Note that the left fissure extends higher than the right one. (b, c) High-resolution CT scans (c obtained at a lower level than b) show extrapleural fat entering the lips of the major fissures (arrow).
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Figure 6b. Superolateral major fissures. (a) Posteroanterior radiograph shows the superolateral major fissures as curving contours with lateral opacity and medial lucency bilaterally (arrows). Note that the left fissure extends higher than the right one. (b, c) High-resolution CT scans (c obtained at a lower level than b) show extrapleural fat entering the lips of the major fissures (arrow).
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Figure 6c. Superolateral major fissures. (a) Posteroanterior radiograph shows the superolateral major fissures as curving contours with lateral opacity and medial lucency bilaterally (arrows). Note that the left fissure extends higher than the right one. (b, c) High-resolution CT scans (c obtained at a lower level than b) show extrapleural fat entering the lips of the major fissures (arrow).
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Figure 7. Vertical fissure line in a child with a ventricular septal defect. Chest radiograph demonstrates the right major fissure as a curving line in the right lower lung field (arrows).
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Figure 8. Vertical fissure line in a woman with abruptio placentae and transient heart failure. Chest radiograph shows the left major fissure as a curving line in the left middle and lower lung fields (arrows).
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Figure 9a. Superomedial major fissure. (a) Chest radiograph shows a superomedial right major fissure (arrows). The minor fissure is seen as double lines. (b) High-resolution CT scan helps confirm the direction of the medial portion of the right major fissure as tangential to the x-ray beam (arrow).
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Figure 9b. Superomedial major fissure. (a) Chest radiograph shows a superomedial right major fissure (arrows). The minor fissure is seen as double lines. (b) High-resolution CT scan helps confirm the direction of the medial portion of the right major fissure as tangential to the x-ray beam (arrow).
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Figure 10a. Intrafissural fat. (a) Lateral chest radiograph shows a triangular area of increased opacity (arrows) mimicking right middle lobe collapse. (b) CT scan reveals that this triangular area represents extrapleural fat extending into the right major fissure (arrow).
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Figure 10b. Intrafissural fat. (a) Lateral chest radiograph shows a triangular area of increased opacity (arrows) mimicking right middle lobe collapse. (b) CT scan reveals that this triangular area represents extrapleural fat extending into the right major fissure (arrow).
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Figure 11a. Lobar pneumonia. Posteroanterior (a) and lateral (b) chest radiographs demonstrate lobar pneumonia of the left upper lobe. The left major fissure is seen as an interface on the lateral view (arrows).
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Figure 11b. Lobar pneumonia. Posteroanterior (a) and lateral (b) chest radiographs demonstrate lobar pneumonia of the left upper lobe. The left major fissure is seen as an interface on the lateral view (arrows).
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Figure 12a. Lobar pneumonia. Posteroanterior (a) and lateral (b) chest radiographs demonstrate lobar pneumonia of the left lower lobe. The left major fissure is seen as an interface on the lateral view (arrows) (cf Fig 11b).
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Figure 12b. Lobar pneumonia. Posteroanterior (a) and lateral (b) chest radiographs demonstrate lobar pneumonia of the left lower lobe. The left major fissure is seen as an interface on the lateral view (arrows) (cf Fig 11b).
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Figure 13a. Interlobar hydropneumothorax. (a) Posteroanterior chest radiograph shows a rounded area with an air-fluid level in the right lower lung field (arrow). (b) High-resolution CT scan shows a collection of air and fluid in the right major fissure (*), a finding that was confirmed on other views (not shown).
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Figure 13b. Interlobar hydropneumothorax. (a) Posteroanterior chest radiograph shows a rounded area with an air-fluid level in the right lower lung field (arrow). (b) High-resolution CT scan shows a collection of air and fluid in the right major fissure (*), a finding that was confirmed on other views (not shown).
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Figure 14a. Localized fibrous tumor of the pleura. (a, b) Posteroanterior (a) and lateral (b) chest radiographs show a lobulated mass in the left middle lung field. (c) High-resolution CT scan demonstrates the relationship of the lesion to the major fissure (arrows).
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Figure 14b. Localized fibrous tumor of the pleura. (a, b) Posteroanterior (a) and lateral (b) chest radiographs show a lobulated mass in the left middle lung field. (c) High-resolution CT scan demonstrates the relationship of the lesion to the major fissure (arrows).
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Figure 14c. Localized fibrous tumor of the pleura. (a, b) Posteroanterior (a) and lateral (b) chest radiographs show a lobulated mass in the left middle lung field. (c) High-resolution CT scan demonstrates the relationship of the lesion to the major fissure (arrows).
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Figure 15. Adenocarcinoma. High-resolution CT scan shows carcinoma invading the right major fissure (arrow) and extending across the fissure into the right lower lobe (T).
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Figure 16. Sarcoidosis. CT scan demonstrates small nodules in the lungs and along the minor (arrowhead) and major (arrow) fissures representing sarcoidosis.
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Figure 17. Minor fissure "crossing" a major fissure. Lateral radiograph shows a minor fissure (arrowheads) that appears to cross a major fissure (arrows) and extends further posteriorly.
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Figure 18a. Right middle lobe collapse (middle lobe syndrome). On a lateral radiograph (b) as well as two CT scans (c, d), the major fissure (arrows) is anterior to the minor fissure (arrowheads). Incorrect localization of a pulmonary nodule may result from the same mechanism.
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Figure 18b. Right middle lobe collapse (middle lobe syndrome). On a lateral radiograph (b) as well as two CT scans (c, d), the major fissure (arrows) is anterior to the minor fissure (arrowheads). Incorrect localization of a pulmonary nodule may result from the same mechanism.
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Figure 18c. Right middle lobe collapse (middle lobe syndrome). On a lateral radiograph (b) as well as two CT scans (c, d), the major fissure (arrows) is anterior to the minor fissure (arrowheads). Incorrect localization of a pulmonary nodule may result from the same mechanism.
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Figure 18d. Right middle lobe collapse (middle lobe syndrome). On a lateral radiograph (b) as well as two CT scans (c, d), the major fissure (arrows) is anterior to the minor fissure (arrowheads). Incorrect localization of a pulmonary nodule may result from the same mechanism.
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Figure 19a. Pneumonia. (a) CT scan demonstrates pneumonia primarily involving the right upper lobe and extending into the lower lobe across the incomplete part of the major fissure (arrow). (b) CT scan obtained just caudad to a clearly delineates incompleteness of the right major fissure (arrow).
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Figure 19b. Pneumonia. (a) CT scan demonstrates pneumonia primarily involving the right upper lobe and extending into the lower lobe across the incomplete part of the major fissure (arrow). (b) CT scan obtained just caudad to a clearly delineates incompleteness of the right major fissure (arrow).
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Figure 20a. Squamous cell carcinoma with right upper lobe collapse. (a) Posteroanterior chest radiograph shows a large tumor associated with collapse of the right upper lobe. (b) CT scan shows a portion of the right upper lobe with aeration (*) from the right lower lobe through the incomplete major fissure (arrow).
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Figure 20b. Squamous cell carcinoma with right upper lobe collapse. (a) Posteroanterior chest radiograph shows a large tumor associated with collapse of the right upper lobe. (b) CT scan shows a portion of the right upper lobe with aeration (*) from the right lower lobe through the incomplete major fissure (arrow).
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Figure 21a. Incomplete fissure sign. (a) Posteroanterior radiograph shows a curving interface in the lateral part of the left lower lung field (arrows), with lateral opacity and medial lucency. (b, c) High-resolution CT scans (c obtained at a lower level than b) show bilateral pleural effusion. The left pleural effusion is bounded by the lateral border of the lower lobe (arrow), which may explain the appearance on the radiograph. The major fissures are complete; thus, "incomplete fissure sign" may also be seen in cases of complete major fissure.
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Figure 21b. Incomplete fissure sign. (a) Posteroanterior radiograph shows a curving interface in the lateral part of the left lower lung field (arrows), with lateral opacity and medial lucency. (b, c) High-resolution CT scans (c obtained at a lower level than b) show bilateral pleural effusion. The left pleural effusion is bounded by the lateral border of the lower lobe (arrow), which may explain the appearance on the radiograph. The major fissures are complete; thus, "incomplete fissure sign" may also be seen in cases of complete major fissure.
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Figure 21c. Incomplete fissure sign. (a) Posteroanterior radiograph shows a curving interface in the lateral part of the left lower lung field (arrows), with lateral opacity and medial lucency. (b, c) High-resolution CT scans (c obtained at a lower level than b) show bilateral pleural effusion. The left pleural effusion is bounded by the lateral border of the lower lobe (arrow), which may explain the appearance on the radiograph. The major fissures are complete; thus, "incomplete fissure sign" may also be seen in cases of complete major fissure.
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Copyright © 2001 by the Radiological Society of North America.
