Ultrasonogram reticulum. Ultrasonogram showing peritonitis caudal to the reticulum in cow 2. The view was obtained from the sternal area using a 5.0-MHz convex transducer. The three layers of the reticular wall (tunica serosa, tunica muscularis, tunica mucosa) are visible because of fluid accumulation. The abomasum is dilated and one echoic abomasal fold is seen. Hypoechoic fluid with a fibrin strand is evident caudal to the reticulum and ventral to the abomasum. 1 ventral abdominal wall, 2 musculophrenic vein, 3 diaphragm, 4 reticulum, 5 abomasum, 6 echoic cell-rich fluid ventrally, 7 fibrin strand, 8 hypoechoic cell-poor fluid, Cr cranial, Cd caudal