Umbilical and Other Abdominal Wall Hernias

Anatomy

After birth, closure of the umbilical ring is the result of complex interactions with the lateral body wall folding in a medial direction, fusion of the rectus abdominis muscles into the linea alba, and umbilical orifice contraction that is aided by elastic fibers from the obliterated umbilical arteries. Fibrous proliferation of the surrounding lateral connective tissue plates and mechanical stress from rectus muscle tension also may help with natural closure. Failure of these closure processes results in an umbilical hernia. The hernia sac is peritoneum and is usually very adherent to the dermis of the umbilical skin. The diameter of the actual fascial defect can range from several millimeters to 5 cm or more. The extent of skin protrusion is not always indicative of the size of the fascia defect. Frequently, small defects can result in alarmingly large proboscis-like protrusions ( Fig. 49.1 ). Thus, it is important to palpate the actual fascial defect by reducing the hernia to assess whether operative or nonoperative treatment is appropriate.