where is hiatus
The hiatus is an opening in the diaphragm (a muscle separating the abdomen and chest) that the esophagus or swallowing tube passes through to reach the stomach. If the hiatus weakens and stretches, part of the stomach and/or the esophagus can squeeze into the chest cavity, producing a hiatal hernia.
In human anatomy, the esophageal hiatus is a hole in the diaphragm through which the esophagus and the vagus nerve pass. It is located in the right crus, one of the two tendinous structures that connect the diaphragm to the spine. Fibres of the right crus cross one another below the hiatus. It is located approximately at level of the tenth thoracic vertebra (T10). The esophageal hiatus is situated in the muscular part of the diaphragm at the level of the tenth thoracic vertebra, and is elliptical in shape.