herniation

Herniation is the protrusion of tissue or an organ through an opening or defect in surrounding structures. It is a general medical term used for conditions in which part of a structure lies outside its normal boundary due to pressure, weakness, or congenital defects. Some herniations are harmless; others require urgent treatment.

Common forms include disc herniation, where the nucleus pulposus protrudes through the annulus fibrosus and may compress nerves; abdominal wall hernias such as inguinal, femoral, and umbilical hernias, in which viscera protrude through weakened fascia; and hiatal hernia, where part of the stomach moves through the diaphragm into the chest. In the brain, herniation occurs when brain tissue shifts due to severe swelling and increased intracranial pressure and is a neurosurgical emergency.

Symptoms vary by type. Disc herniation typically causes back or neck pain with radiating leg or arm symptoms, numbness, or weakness. Abdominal hernias present as a visible lump, swelling or discomfort, especially with lifting or coughing, with risk of incarceration or strangulation in some cases. Hiatal hernia may cause reflux, heartburn, regurgitation, and sometimes swallowing difficulties. Brain herniation can produce rapid changes in consciousness, abnormal posturing, pupil changes, and respiratory decline.

Diagnosis relies on history and examination, with imaging as needed: MRI for disc herniation, ultrasound or CT for abdominal hernias, endoscopy or barium studies for reflux, and CT or MRI for brain herniation. Treatments range from observation and physical therapy to surgical repair of the hernia, and in urgent cases to measures that relieve intracranial pressure.

Prognosis varies by type; small, reducible hernias have good outcomes after repair, while incarcerated or strangulated hernias carry higher risk. Brain herniation carries significant mortality without prompt treatment. Prevention focuses on risk-factor management and early treatment of underlying conditions, such as maintaining a healthy weight, avoiding excessive strain, and treating reflux or intracranial pressure when present.