Spigelian Hernia with Homolateral Direct Inguinal Hernia: A Rare Case Report.

A Spigelian hernia (or lateral ventral hernia) is a hernia through the spigelian fascia, which is the aponeurotic layer between the rectus abdominal muscle medially and the semilunar line laterally. There is a common misconception that they protrude below the arcuate line owing to deficiency of the posterior rectus sheath at that level, but in fact, the defect is almost always above the arcuate line. These are interparietal hernias, meaning that they do not lie below the subcutaneous fat but penetrate between the muscles of the abdominal wall; therefore, there is often unnoticeable swelling. Spigelian hernias are usually small, and therefore, the risk of strangulation is high. Most occur on the right side (4-7th decade of life).