saber sheath trachea
Saber-sheath trachea refers to diffuse coronal narrowing of the intrathoracic portion of the trachea with the concomitant widening of the sagittal diameter. It is not uncommon and is pathognomonic for chronic obstructive pulmonary disease (COPD) .
The sagittal:coronal diameter is over 2:1 and the extra-thoracic portion of the trachea is not narrowed. The supporting tracheal cartilage is usually thickened and densely calcified .
Marked decrease in the coronal diameter of the intrathoracic trachea associated with an increase in its sagittal diameter.
Additional features may include:
- inward bowing or displacement of the lateral tracheal walls as a result of cartilage weakness
- mild intrathoracic tracheal wall thickening
- ossification of tracheal rings
- during forceful expiration, there may be further inward bowing