What term refers to the upper portion of the abdomen bordered by the costal margin?

The term that refers to the upper portion of the abdomen, which is bordered by the costal margin, is indeed the epigastrium. This anatomical region is located just below the rib cage and above the umbilical region, making it a significant area for assessing various abdominal conditions.

The epigastrium can often be a focal point in examinations because it houses vital organs such as the stomach, liver, and pancreas. Understanding this region is essential for medical professionals when evaluating patients with abdominal pain or performing clinical assessments.

In contrast, the hypogastrium is the lower part of the abdomen, while the mesogastrium refers to the middle section of the abdomen. The cardiac region is not an accepted term for this abdominal area, as it primarily relates to the heart's anatomical location. Recognizing the distinctions among these terms is crucial for accurate communication in medical settings.