Involuting corpus luteum. This ovary (arrow) was seen in a 14-year-old with ipsilateral lower abdominal pain, and was thought on POCUS to be torsed despite the presence of flow and isoechogenicity with the unaffected ovary. The structure demonstrated asymmetry in size when compared with the unaffected ovary, peripheralized follicles (arrowheads), and surrounding free fluid (triangle).