1. The Wonderful World of the Windpipe: A Review of Central Airway Anatomy and Pathology 
David A. Lawrence, MD, Brittany Branson, MD, Isabel Oliva, MD, Ami Rubinowitz, MD 
Canadian Association of Radiologists Journal 
Volume 66, Issue 1, Pages (February 2015)
DOI: /j.carj
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2. Figure 1
Tracheal wall anatomy. Note the horseshoe-shaped cartilaginous ring extending along the anterior and lateral walls of the trachea. The mucosa and submucosa are difficult to delineate on computed tomography in a normal trachea. This figure is available in colour online at
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3. Figure 2
Normal tracheal anatomy on computed tomography. Axial computed tomography image of the trachea with bone windows demonstrates the anterior cartilaginous ring (arrows) as well as the membranous posterior wall of the trachea where the trachealis muscle is located (arrowhead).
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4. Figure 3
Normal inspiratory and expiratory computed tomography images. On inspiration (A), note that the membranous wall of the trachea bows posteriorly (arrow). On expiration (B), the membranous wall bows anteriorly (arrowhead). Note that the anterolateral walls change little in their morphologic appearance, due to the cartilaginous support.
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5. Figure 4
Fifty-year-old man with tracheopathia osteochondroplastica, detected incidentally at computed tomography. (A and B) Axial computed tomography images demonstrate nodular thickening of the anterior and lateral tracheal wall (arrow), which spares the posterior wall of the trachea. Some of the tracheal wall nodules are calcified (arrowheads). The disease primarily involves the lower two thirds of the trachea, and may extend into the mainstem, segmental, or lobar bronchi. (C) Bronchoscopic image from the same patient demonstrating the multiple small nodules involving the anterior and lateral walls of the trachea, but sparing the posterior wall. This figure is available in colour online at
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6. Figure 5
Relapsing polychondritis. Multiple axial noncontrast computed tomography images demonstrate tracheal wall thickening, extending from the thoracic inlet (A) to the aortic arch (B) to the level of the carina (C). The anterior and lateral walls of the trachea are characteristically involved (arrows). The tracheal wall may also become calcified (arrowheads). This disease typically affects cartilage throughout the body, including the ears, nose, and joints.
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7. Figure 6
Fifty-year-old patient with Wegener's granulomatosis. (A) Axial computed tomography image of man thorax with soft tissue window demonstrates diffuse, circumferential tracheal wall thickening (arrows). (B and C) Associated imaging findings of Wegener's granulomatosis on axial computed tomography image of the thorax with lung window include lung nodules which may cavitate (arrowhead in B) and evidence of chronic sinus disease (C) on coronal reformatted image from computed tomography of the sinuses with mucoperiosteal thickening and destruction of the osseous structures of the paranasal sinuses.
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8. Figure 7
Inflammatory bowel disease associated tracheal wall thickening. Axial computed tomography images of the thorax with soft tissue windows show mild, diffuse circumferential wall thickening of the trachea (arrows) extending from the thoracic inlet (A) to the level of the aortic arch (B). This is a nonspecific imaging appearance and history is necessary for the diagnosis. (C) Same patient, axial contrast enhanced computed tomography image of the pelvis demonstrates diffuse wall thickening of the rectosigmoid colon (arrowheads). The patient had a history of ulcerative colitis and presented with an acute flare of his disease.
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9. Figure 8
Post intubation tracheal stenosis in a 2-year-old, ex-premature infant. (A) Axial computed tomography image of the thorax with soft tissue window demonstrates circumferential tracheal wall thickening in the upper thoracic trachea (arrowheads). (B) Coronal minimum intensity projection image of the thorax demonstrates the focal area of tracheal narrowing at this same level (arrows). The patient also had multiple cystic spaces in the lungs as a sequela of bronchopulmonary dysplasia.
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10. Figure 9
Tracheobronchial papillomatosis. (A) Axial computed tomography image of the thorax demonstrates numerous nodules along the tracheal and bronchial walls. The nodules are typically smooth and can vary in size. (B) Coronal reformatted computed tomography image of the thorax demonstrates numerous nodules along the tracheal and bronchial walls. (C) Image from bronchoscopy demonstrating one of the lesions. This figure is available in colour online at
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11. Figure 10
Twenty-eight-year-old man with shortness of breath due to rhinoscleroma. (A) Coned down posteroanterior radiograph of the chest demonstrates severe tracheal narrowing (arrows). (B) Axial computed tomography image of the chest with soft tissue window at the level of the thoracic inlet demonstrates a soft tissue nodule (arrowhead) along the right tracheal wall that results in severe narrowing of the trachea. The tracheal wall was diffusely thickened elsewhere as well (not shown).
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12. Figure 11
Extrinsic compression and invasion of the trachea by esophageal carcinoma. Coronal reformatted (A) and axial (B) contrast enhanced computed tomography images of the chest using soft tissue windows demonstrate a heterogeneously enhancing mass (asterisk) arising from the esophagus, directly invading and severely narrowing the trachea (arrow). The patient had a significant smoking history and presented with worsening dyspnea. (C) Lateral view from an esophagram demonstrates severe narrowing of the midesophagus (arrowheads), corresponding to the neoplasm from the computed tomography images.
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13. Figure 12
Squamous cell carcinoma of the trachea. Axial computed tomography images with soft tissue (A) and lung (B) windows just below the thoracic inlet demonstrate a large soft tissue mass arising from the posterior wall of the trachea (arrows). Also note the direct mediastinal extension of tumour (arrowheads).
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14. Figure 13
Endoluminal mass secondary to adenoid cystic carcinoma. Axial computed tomography images with lung (A) and soft tissue (B) windows through the upper thorax demonstrate a soft tissue mass along the right anterior aspect of the tracheal wall (arrows), which is a nonspecific imaging appearance. Subsequent bronchoscopic biopsy proved the lesion to be an adenoid cystic carcinoma.
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15. Figure 14
Thirty-year-old man with chronic cough and hemoptysis secondary to an obstructing endobronchial carcinoid tumour. Noncontrast axial computed tomography images with lung (A) and soft tissue (B) windows demonstrate a well-circumscribed, soft tissue mass obstructing the origin of the left lower lobe bronchus (arrows). Note the calcifications within the mass (arrowhead), which up to one third of carcinoid tumours will contain.
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16. Figure 15
Displaced right tracheal bronchus (“pig bronchus”). Coronal minimum intensity projection reformatted computed tomography image of the thorax demonstrates the right upper lobe bronchus arising abnormally from the distal trachea (arrow), instead of arising from the right main stem bronchus. The normal type of branching pattern to the right upper lobe is absent, which makes this a displaced type of tracheal bronchus.
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17. Figure 16
Sixty-two-year-old woman with wheezing and asthma-type symptoms. Axial computed tomography image through the upper thorax with lung windows during expiration demonstrates excessive collapsibility (>50% of the normal inspiratory diameter) of the trachea with marked anterior bowing of the posterior wall (arrow). This appearance results in the so-called “frown sign” of tracheomalacia.
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18. Figure 17
Seventy-year-old man with smoking history, chronic obstructive pulmonary disease, and a saber-sheath trachea at imaging. Frontal (A) and lateral (B) chest radiographs demonstrate narrowing of the trachea in the transverse dimension (arrows) and widening of the trachea in the anteroposterior dimension (arrowheads). (C) Axial computed tomography image with lung windows demonstrates decreased transverse diameter of the trachea (arrows) with an increase in the AP diameter (arrowheads).
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19. Figure 18
Left bronchus foreign body (tack) in a 7-year-old child. Frontal (A) and lateral (B) radiographs of the chest demonstrate a radiopaque foreign body in the distal left mainstem bronchus/origin of the left lower lobe bronchus (arrows). Radiographically, it appears to be a tack, which corresponded to the clinical history and bronchoscopic findings. Resultant partial atelectasis of the left lower lobe is also present, best seen on the lateral view (arrowhead).
Canadian Association of Radiologists Journal  , 30-43DOI: ( /j.carj )
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