Question

which of the following is considered a direct sign of atelectasis?
pleural effusion
mediastinal deviation
tracheal deviation
displacement of fissures

Explanation:

Atelectasis refers to the collapse or closure of lung tissue. Displacement of fissures is a direct sign as it directly shows the altered position of lung structures due to the collapsed lung tissue. Pleural effusion is fluid in the pleural space (not directly from atelectasis). Mediastinal and tracheal deviation are indirect signs as they are secondary to the volume loss from atelectasis (pulling or shifting due to the collapsed lung's effect on surrounding structures).

Answer:

displacement of fissures