Ultrasonogram showing peritonitis between the rumen and left abdominal wall. Ultrasonogram showing peritonitis between the rumen and left abdominal wall in cow 2. The view was obtained using a 5.0-MHz convex transducer placed in the 12th intercostal space (lower third) on the left side. A large amount of hypoechoic fluid containing echoic fibrin is evident between the rumen and left abdominal wall. 1 abdominal wall, 2 fluid accumulation, 3 fibrin, 4 greater omentum, 5 rumen wall, Ds dorsal, Vt ventral