A neuromuscular basis for the development of right inguinal hernia after appendectomy.

Abdominal muscular contractions may have a protective influence against the development of indirect inguinal hernia. A portion of the transversus abdominus muscles acts on the internal inguinal rings and produces a closure mechanism during voluntary abdominal muscular activity. It follows, therefore, that injury or inactivation of this mechanism may be an etiologic factor in the development of indirect inguinal hernia. One cause of injury to this mechanism is denervation and regional muscle paralysis occurring during a surgical procedure. Electromyographic findings support the hypothesis that paralysis of inferior fibers of the transversus abdominus muscle occurred after appendectomy, and may have been important in the development of an inguinal hernia.