The esophageal hiatus: what is the normal size?

A hiatal hernia is defined as the protrusion of intra-abdominal organs through a dilated esophageal hiatus. The esophageal hiatus and its function have been described extensively, but an exact anatomical determination of its normal size is lacking. It seems important to define the normal size, as crural closure is an important part of surgical treatment of gastroesophageal reflux disease (GERD) and hiatal or paraesophageal hernias. The aim of this study was to determine normal values for the size of the esophageal hiatus.

In a prospective study 50 consecutive cadaver autopsies were performed between February and May 2008. The subjects had died from several diseases not related to GERD. Size of the esophageal hiatus was measured after opening the abdominal cavity before extirpation of any organs. Distance of the cardia and gastroesophageal junction and position of the angle of His were further measured. A formula was used to calculate the hiatal surface area (HSA). Results were analyzed regarding subject height, weight, body mass index (BMI), and chest circumference.

In all 50 cadavers (24 male/26 female) the autopsy was performed and all measurements were obtained. Mean age was 74 years (40-90 years), mean height was 1.68 m (1.39-1.83 m), mean weight was 71 kg (40-120 kg), and mean body mass index (BMI) was 25 kg/m(2) (14-40 kg/m(2)). Mean chest circumference was 101 cm (75-178 range). Mean HSA was 5.84 cm(2) (3.62-9.56 cm(2)). In all cadavers the gastroesophageal junction was intraabdominal, the mean distance to the angle of His was 3.6 cm (2.7-4.6 cm), the mean length of the right and left crura was similar at 3.6 cm (2.7-4.6 cm), and the opening segment had a mean length of 2.4 cm (1.7-4.0 cm).

The mean HSA was determined in these normal subjects to be 5.84 cm(2). It was directly proportional to chest circumference and independent of height, weight, BMI, and gender.