ABSTRACT
Damage to the wall of air sacs, caused by trauma or chronic infection, leads to air leakage from the respiratory system to the subcutaneous tissues (emphysema). This is most common in the neck region, but damage to the body wall can lead to leakage on other locations. In cases of rupture of the air sac in the neck, the neck will be distended ( Fig. 36.1 ). In cases of generalized emphysema, other parts of the bird might appear swollen.
