Normal and collapsed trachea in the dog: scanning electron microscopy study.

Scanning electron microscopy was used to examine canine tracheal cartilage and to determine the relationship between the fibrous and amorphous matrix in this tissue. Collapsed tracheal (CT) cartilage was hypocellular, compared with normal tracheal cartilage. The amorphous matrix of CT cartilage had a porous, fissured texture and did not have the homogeneous appearance of normal tracheal cartilage. Capillaries were seen to pass through CT cartilage. Randomly distributed connective tissue fibers, evident in CT cartilage matrix, were frequently attached to irregular shapes and sizes of amorphous matrix.