Scabbard Trachea; True is?
SCABBARD (SABER-SHEATH) TRACHEA

Flattening of trachea caused by lateral compression by swellings or tumors.
Causes: Carcinoma thyroid, thyroiditis, carcinoma larynx, goitre.
Flattening of trachea
Caused by lateral compression by swellings
Caused by lateral compression by tumors
All of the above