fothergill's sign fothergill's sign fothergill's sign is a medical sign. if a mass in the abdominal wall does not cross midline and does not change with flexion of the rectus muscles, this is a positive sign for a rectus sheath hematoma. fothergill's signdifferential diagnosisrectus sheath hematoma it is named for english obstetrician william edward fothergill, who described features of rectus sheath hematomas in a 1926 article in the british medical journal entitled "haematoma in the abdominal wall simulating pelvic new growth". in rectus sheath haematoma, the haematoma produces a mass that does not cross the midline and remains palpable when the rectus muscle is tense.