a 19 year old college student presents to student health services with a 2-day history of mildly diffuse abdominal pain, low grade temp, and mild nausea. he was out drinking with his friends over the weekend and ate pizza and wings. during your exam you ask the patient to lie on his or her left side while the right thigh is flexed backward, and you elicit left lower quadrant pain. what is the name of this sign