Which type of hernia cannot be reduced?

Incarcerated hernias are characterized by the inability to reduce the herniated tissue back into the abdominal cavity. This occurs when a segment of the bowel or other tissue becomes trapped in the hernia sac and cannot be returned to its normal position. The tissue may still have a blood supply, which distinguishes it from a strangulated hernia, where there is compromised blood flow, leading to ischemia and potentially necrosis.

Incarceration is a critical condition that requires surgical intervention, but it does not always involve ischemic changes. Recognizing an incarcerated hernia is essential in emergency medicine, as they can lead to severe complications if not treated promptly.

The other types of hernias mentioned have distinct characteristics: strangulated hernias are indeed also not reducible because of compromised blood supply, often requiring urgent surgical evaluation; however, the question specifically asks for the type that is defined primarily by the inability to be reduced, which aligns more directly with the description of an incarcerated hernia. Umbilical hernias can often be reduced, especially in infants and young children, further emphasizing the unique nature of incarceration.