A marked difference in echogenicity between the anterior and posterior parts of the pancreatic head was demonstrated by pancreatic ultrasound in 4 patients. This finding could not be related to local pancreatic or peripancreatic pathology. In all patients the dorsal portion of the head, including the uncinate process, appeared less echogenic than the ventral part of the head, body, and tail. The level of demarcation was identical in all 4 cases, coinciding with the expected fusion line of the embryological dorsal and ventral pancreatic origin. Pathology available in 1 patient showed an uneven lipomatosis as an explanation for this hitherto unreported observation.