[1] They are located on the lateral sides of the abdominal wall respectively, inferior to (below) the thoracic cage, being separated by the epigastrium.

[4] The word once referred only to the soft portion of the abdomen between the rib cage and the navel (the region once believed to be the seat of hypochondriasis), but it is not used that way in modern anatomy's schemes for the regions of the abdomen.

[5] Some sources have disputed usage of the term for the parts of the anterior abdominal wall below the costal margins.

The region named the right hypochondrium exists anatomically, but is almost totally under the chest wall.

[6] Clinically speaking, symptoms and signs arising from this region are of great importance and have a specific list of diseases in their differential diagnoses.