What is spigelian hernia?

Interparietal hernia at arcuate line through spigelian point, above umbilicus (10%) or below (90%) junction of linea semilunaris/semicircularis soft reducible mass lateral to rectus muscle impulse cough strangulation common, obesity chronic cough and old age precipitate it females>50 yrs Tx: open or laparoscopic Mesh repair