Detection of Myofascial Herniation on Dynamic Sonography and Magnetic Resonance Imaging

Muscle hernia is an uncommon cause of leg swelling. It can be detected in the early stages only if there is a high index of suspicion. It is common in lower extremity compared to the upper extremity. Tibialis anterior muscle in the leg is commonly involved. Dynamic sonography and magnetic resonance imaging (MRI) are the mainstay in their diagnosis, which demonstrate a facial defect with herniation of muscle fibers. We report a case of 23-year-old male patient who presented with a painless swelling in the anterolateral aspect of the left upper leg. Dynamic sonography done with high-resolution probe demonstrated a defect in fascia overlying tibialis anterior with herniation of outer muscle fibers which increased during dorsiflexion and reduced in the supine position at rest. MRI of the left leg confirmed the findings.