Final answer:
The fundus is the region of the stomach that is superior to the gastroesophageal junction and is in contact with the diaphragm.
Step-by-step explanation:
The region of the stomach that is superior to the gastroesophageal junction and contacts the inferior and posterior surface of the diaphragm is known as the fundus. Located above and to the left of the cardia, the fundus is the dome-shaped part that sits superior to the gastroesophageal junction. The fundus' positioning allows it to come into contact with the diaphragm. The stomach itself is divided into four main regions: the cardia (or cardiac region), fundus, body, and pylorus, each serving different functions in the process of digestion, with the muscularis enabling the stomach to vigorously churn and mix food.