Psoas sign is positive when there is an abdominal pain as the patient moves his leg against resistance . The abdominal pain is associated with relfexive or direct irritation of the psoas muscle. Positive psoas sign usually indicates localizes abscess or appendicitis. Psoas sign may be elicited on the right or left sides. Psoas sign is elicited after performing a complete abdominal examination in a patient who complain of abdominal or lower back pain.