Tracheomalacia (1 of 2)
Even at its maximum functional caliber, this trachea is severely narrowed (stenotic), due to injury from long-term intubation and tracheotomy. Not yet visible here is the tracheomalacia component (illustrated in image 2). A small granuloma is also visible on the right edge of the image.

Tracheomalacia (2 of 2)
Additional functional collapse (the tracheomalacia component), with both inspiration and expiration.

Tracheal hyperflexibility (1 of 6)
This patient has COPD as well as a "wet and productive" sounding cough. The explanation for this is not actual mucus, but tracheal vibration that sounds like a mucus-y cough. This panoramic view shows inspiration and normal abduction of the vocal cords. As we will see in photo 3, the trachea is patent at this moment.

Tracheal hyperflexibility (2 of 6)
Expiratory partial closure of the true vocal cords, similar to the lip-pursing maneuver persons with COPD often use to prevent lower airway collapse. As we see in photo 4, collapse is happening in spite of this lip-pursing maneuver.

Tracheal hyperflexibility (3 of 6)
Mid-trachea during deep inspiration, corresponding to the vocal cord position in photo 1. The white arrow indicates a speck of mucus which will also be seen in photo 4.

Tracheal hyperflexibility (4 of 6)
Mid-trachea, showing the same position as photo 3 but now during expiration. The membranous tracheal wall is bulging inward and nearly blocking the trachea. A wheezing sound is heard as air whistles though this narrow lumen (the expected lumen is indicated by the curved dotted line). The same speck of mucus that was seen in photo 3 is indicated again by the white arrow.

Tracheal hyperflexibility (5 of 6)
A little farther down the trachea, during inspiration.

Tracheal hyperflexibility (6 of 6)
At the same position as photo 5, during a cough. The membranous trachea not only bulges inward, but it also vibrates impressively (note blur), creating a deep and rumbling cough whose "wet" quality is not actually from mucus, but from vibration of the tracheoesophageal party wall.