The extra-peritoneal fat deposit along the midline of the anterior abdominal wall was scanned with B-mode gray scale linear array ultrasonic diagnostic apparatus in 52 normal adults and 19 abdominal surgical patients. The morphology of the extra-peritoneal fat determined by ultrasonography preoperationly and that observed during operations were compared and found similar in 92.6% (14/15). Extra-peritoneal fat along the midline of the anterior abdominal wall usually presented as a ribbon-like deposit from xiphoid process to symphysis pubis Its thickness was directly proportional to that of subcutaneous fat of the abdominal wall

but was out of proportion to the patients body weight. In practice

misdiagnosis of the extra-peritoneal fat at the infraxiphoid region as a low echogenic lesion of the anterior gastric wall or the upper surface of the left lobe of the liver may be made in. ultrasonogaphy. Obviously a accurate recognition of such a finding is of significance in differential diagnosis.