A hiatal hernia is a medical condition where a portion of the stomach pushes upward through the diaphragm and into the chest cavity. The diaphragm is a muscle that separates the chest cavity from the abdomen and helps with breathing. The opening in the diaphragm through which the esophagus passes is called the hiatus. In a hiatal hernia, the stomach bulges through this opening.

There are two main types of hiatal hernias:

1. Sliding hiatal hernia: This is the most common type. In a sliding hiatal hernia, the junction where the esophagus and stomach meet (known as the gastroesophageal junction) and a portion of the stomach slide up into the chest through the hiatus. This movement is typically caused by the weakening of the muscles and tissues that hold the stomach in place.

2. Paraesophageal hiatal hernia: This type is less common but more concerning. In a paraesophageal hernia, a portion of the stomach squeezes through the hiatus and remains there, beside the esophagus, instead of sliding back down. This can lead to complications if the hernia becomes trapped (incarcerated) or if the blood supply to the herniated portion is compromised (strangulated).

Hiatal hernias can occur at any age and may not always cause noticeable symptoms. However, they can sometimes lead to gastroesophageal reflux disease (GERD) due to the weakened barrier between the esophagus and the stomach. Symptoms of hiatal hernia and GERD can include heartburn, regurgitation, chest pain, difficulty swallowing, and a feeling of fullness after meals.

Treatment options for hiatal hernia and associated symptoms may include lifestyle changes (e.g., avoiding trigger foods, losing weight), medications to reduce acid production or improve esophageal motility, and, in severe cases, surgery to repair the hernia and reinforce the hiatus.

It's important to consult with a healthcare professional for an accurate diagnosis and appropriate management of a hiatal hernia.