Tibialis Anterior Muscle Hernia: A Case of Chronic, Dull Pain and Swelling in Leg Diagnosed by Dynamic Ultrasonography

BACKGROUND Symptomatic muscle hernias are not uncommon in the lower extremities and are a rare cause of chronic leg pain. They are most commonly seen in the tibialis anterior muscle, occurring through fascial defects, usually after trauma. There are about 200 cases of muscle hernias described in the literature. The diagnosis is challenging as most of the patients present with non-specific chronic leg pain. Dynamic muscle ultrasonography at rest and at stress is often used for the diagnosis. CASE REPORT We describe a case of tibialis anterior muscle hernia presenting with persistent dull pain and swelling along the anterior aspect of the leg on straining the leg muscles. Dynamic ultrasonography was performed, which showed a defect in the fascial sheath of the muscle through which the tibialis anterior muscle herniated and produced a focal bulge along the anterior aspect of the leg. Based upon physical examination and dynamic ultrasonographic findings, a diagnosis of tibialis anterior muscle hernia was made. CONCLUSIONS Tibialis anterior muscle hernia is a rare diagnosis and should be included in the differential diagnosis in a patient with chronic leg pain and swelling. Dynamic ultrasound is crucial in confirming the diagnosis and should be done on straining the muscles of the affected limb.