A hernia is the protrusion of an organ, tissue, or part of an organ through a weakened spot or opening in the wall of the body cavity that normally contains it. The condition commonly affects the abdomen, where internal contents push through the protective layer of muscle and fascia. Hernias are common, and categorization by anatomical location aids in diagnosis and determining the appropriate treatment plan. The most frequent types are found in the groin, the anterior abdominal wall, and the diaphragm.
Groin Hernias
Hernias occurring in the groin region are the most common type and are categorized as either inguinal or femoral, distinguished by their exact location relative to the inguinal ligament. An inguinal hernia involves tissue pushing through the inguinal canal, a passageway in the lower abdominal wall. This type accounts for approximately 75% of all abdominal wall hernias, affecting men far more often than women.
Inguinal hernias are further divided into two subtypes: direct and indirect, based on their path into the canal. An indirect inguinal hernia occurs when abdominal contents follow the path of the spermatic cord or round ligament, entering the inguinal canal through a pre-existing opening called the deep inguinal ring. This type is often congenital and is more common in younger individuals. Conversely, a direct inguinal hernia pushes directly through a weak spot in the posterior wall of the inguinal canal, bypassing the deep ring. This type is typically acquired later in life, often due to chronic strain and the natural weakening of the abdominal muscles over time.
The femoral hernia also appears in the groin area but is anatomically distinct, emerging through the femoral canal just below the inguinal ligament, near the upper thigh. Femoral hernias are much less common than inguinal hernias, representing only about 4% of groin hernias. This type is observed more frequently in women. Femoral hernias carry a higher risk of complications, such as strangulation, because the opening they pass through is narrower and more rigid. This narrow neck can more easily trap the protruding tissue, requiring immediate surgical intervention.
Abdominal Wall Hernias
Abdominal wall hernias involve weaknesses in the anterior abdominal wall outside of the groin area. Umbilical hernias protrude through the umbilical ring, a naturally weak spot near the navel. While this type can occur in adults, they are most frequently seen in infants, where they usually close without intervention. Adult cases typically require surgical repair.
Epigastric hernias occur in the midline of the upper abdomen, specifically through the linea alba, the connective tissue that runs between the breastbone and the navel. These hernias are generally composed of fatty tissue and are often small, sometimes causing no symptoms at all. They are distinct from umbilical hernias by being located above the belly button.
Incisional hernias develop at the site of a previous surgical incision, which is a common location for a weakened abdominal wall. The tissue, often bowel or fat, pushes through the scar tissue that failed to heal with sufficient strength. This type of hernia can affect up to 15% of patients following abdominal surgery, with the risk increasing if the patient develops a surgical site infection. The location of the protrusion is directly correlated with the scar line from the prior operation.
Diaphragm Hernias
Hernias involving the diaphragm are known as hiatal hernias. This type occurs when a portion of the stomach pushes upward into the chest cavity through the esophageal hiatus, the opening in the diaphragm through which the esophagus passes. Hiatal hernias are common, especially in people over the age of 50.
The most prevalent form is the sliding hiatal hernia, also known as Type I. In this case, the junction where the esophagus meets the stomach slides up into the chest cavity through the hiatus. This movement is often associated with symptoms of gastroesophageal reflux disease, or GERD, such as heartburn.
The less common type is the paraesophageal hiatal hernia. Here, the stomach and the esophageal-stomach junction remain in their normal positions, but a part of the stomach squeezes through the hiatus and sits next to the esophagus. Although paraesophageal hernias may not cause immediate symptoms, they pose a greater risk of the stomach becoming trapped or twisted, which can compromise its blood supply.