
A hernia is the abnormal exit of tissue or an organ, such as the bowel, through the wall of the cavity in which it normally resides. Hernias come in a number of types. Most commonly they involve the abdomen, specifically the groin. Groin hernias are most commonly of the inguinal type but may also be femoral. Other hernias include hiatus, incisional, and umbilical hernias. Symptoms are present in about 66% of people with groin hernias. This may include pain or discomfort, especially with coughing, exercise or going to the bathroom. Often, it gets worse throughout the day and improves when lying down. A bulging area may appear that becomes larger when bearing down. Groin hernias occur more often on the right than left side. The main concern is strangulation, where the blood supply to part of the bowel is blocked. This usually produces severe pain and tenderness in the area. Hiatus, or hiatal, hernias often result in heartburn but may also cause chest pain or pain with eating.

Brain herniation is a potentially deadly side effect of very high pressure within the skull that occurs when a part of the brain is squeezed across structures within the skull. The brain can shift across such structures as the falx cerebri, the tentorium cerebelli, and even through the foramen magnum. Herniation can be caused by a number of factors that cause a mass effect and increase intracranial pressure (ICP): these include traumatic brain injury, intracranial hemorrhage, or brain tumor.

An epigastric hernia is a type of hernia that causes fat to push through a weakened area in the walls of the abdomen. It may develop in the epigastrium. Epigastric hernias are more common in adults and usually appear above the umbilical region of the abdomen. It is a common condition that is usually asymptomatic although sometimes their unusual clinical presentation can present a diagnostic dilemma for the clinician. Unlike the benign diastasis recti, epigastric hernia may trap fat and other tissues inside the opening of the hernia, causing pain and tissue damage. It is usually present at birth and may appear and disappear only when the patient is doing an activity that creates abdominal pressure, pushing to have bowel movements, or crying.

Grynfeltt-Lesshaft hernia is a herniation of abdominal contents through the back, specifically through the superior lumbar triangle, which is defined by the quadratus lumborum muscle, twelfth rib, and internal oblique muscle.

Hernia repair refers to a surgical operation for the correction of a hernia—a bulging of internal organs or tissues through the wall that contains it. It can be of two different types: herniorrhaphy; or hernioplasty. This operation may be performed to correct hernias of the abdomen, groin, diaphragm, brain, or at the site of a previous operation. Hernia repair is often performed as an ambulatory procedure.

Internal hernias occur when there is protrusion of an internal organ into a retroperitoneal fossa or a foramen in the abdominal cavity. If a loop of bowel passes through the mesenteric defect, that loop is at risk for incarceration, strangulation, or for becoming the lead point of a small bowel obstruction. Internal hernias can also trap adipose tissue (fat) and nerves. Unlike more common forms of hernias, the trapped tissue protrudes inward, rather than outward.

Perineal hernia is a hernia involving the perineum. The hernia may contain fluid, fat, any part of the intestine, the rectum, or the bladder. It is known to occur in humans, dogs, and other mammals, and often appears as a sudden swelling to one side of the anus.
Petit's hernia is a hernia that protrudes through the lumbar triangle. This triangle lies in the posterolateral abdominal wall and is bounded anteriorly by the free margin of external oblique muscle, posteriorly by the latissimus dorsi and inferiorly by the iliac crest. The neck is large, and therefore this hernia has a lower risk of strangulating than some other hernias.

A Spigelian is the type of ventral hernia where aponeurotic fascia pushes through a hole creating a bulge. It appears in the abdomen lower quadrant between an area of dense fibrous tissue and abdominal wall muscles causing a

An umbilical hernia is a health condition where the abdominal wall behind the navel is damaged. It may cause the navel to bulge outwards—the bulge consisting of abdominal fat from the greater omentum or occasionally parts of the small intestine. The bulge can often be pressed back through the hole in the abdominal wall, and may "pop out" when coughing or otherwise acting to increase intra-abdominal pressure. Treatment is surgical, and surgery may be performed for cosmetic as well as health-related reasons.