Fig. 7.

Ventrodorsal survey radiographs. (A) A normal African gray parrot (P erithacus). Note the hourglass appearance of the cardiohepatic waist with abundant and symmetric airsac space on either side of it. (B) Moderate dilation of the proventriculus (arrows) in an African gray parrot with PDD. The proventriculus extends laterally beyond the liver edge at the expense of airsac space on the left. (C) Severe dilation of the proventriculus and ventriculus in a yellow-crested cockatoo (Cacatua sulphurea) with PDD. There is complete loss of the cardiohepatic waist and airsac space is markedly diminished bilaterally. Due to the general loss of peritoneal detail in this bird, a contrast study is indicated.