Sonographic examination of muscle herniation.

Muscle herniation is defined as a protrusion of a portion of a muscle through a defect of the muscle fascia. Although muscle herniation usually is only a cosmetic problem, the condition can lead to spontaneous pain, cramp, or local tenderness. We report eight patients in whom sonographic examination was used to diagnose a muscle herniation. The sonographic technique demonstrates the muscle bulging and the fascial defect. Dynamic examination permits the demonstration of reduction of the herniated muscle substance when pressure is applied through the probe. Although the diagnosis of muscle herniation can be suspected at physical examination, nevertheless sonography can be useful in confirmation.