Complex sentence: The perineum is a region of exception for obstetricians and gynecologists who regard the perineal body in the perinuem to be an anatomical center and an important landmark.
Split into simpler sentences: The perineum is a region of exception for obstetricians and gynecologists (OB/GYNs). OB/GYNs regard the perineal body in the perinuem to be an anatomical center and an important landmark.