Hernia

A hernia forms when an organ, or part of one, pushes out through an opening or weakened patch in the muscle and connective tissue meant to contain it. Most involve the abdominal wall. Inguinal hernias in the groin are the most common kind and mainly affect men; others include femoral hernias at the top of the thigh, umbilical hernias at the navel, incisional hernias through an old surgical scar, and hiatal hernias, in which the upper stomach slides through the diaphragm into the chest.

Some weak points exist from birth, such as a groin passage that never sealed during fetal development; others appear with age, injury or surgery. Anything that raises pressure inside the abdomen, such as a chronic cough, straining on the toilet or heavy lifting, can force tissue through. The typical sign is a lump that grows on coughing or standing and shrinks on lying down. Examination usually settles the diagnosis, with ultrasound or CT when it is unclear.

The main danger is incarceration, when the contents get stuck, and strangulation, when their blood supply is cut off and the trapped tissue starts to die, a surgical emergency. Repair, by open or laparoscopic surgery, puts the contents back and closes or reinforces the defect, often with mesh. Small inguinal hernias with few symptoms are sometimes just watched.