Lumbar hernia is classically described as arising from the superior (Grynfeltt's) lumbar triangle or the inferior (Jean-Louis Petit's) lumbar triangle. The present anatomical study based on a computed tomography examination performed in a patient with lumbar hernia, has led to the suggestion that lumbar hernias cross the lumbar wall through a musculoaponeurotic tunnel, whose deep and superficial openings are the superior and inferior lumbar triangles, respectively.