The ultrasound manifestations of appendicitis are as follows: 1) thickening of the appendix, local edema, and inflammatory changes, which are ultrasound manifestations of simple congestive appendicitis. 2) exudation around the appendix and encapsulation of the omentum, structural disorders, and inflammatory changes in the ileocecal region, which are ultrasound manifestations of septic appendicitis. 3) local exudation of the appendix, resulting in fluid in the abdominopelvic cavity, fluid in the subhepatic cavity, fluid in the iliac fossa, and a series of inflammatory changes, which are ultrasound manifestations of perforated appendicitis. This change is the ultrasound manifestation of perforated appendicitis. 4. Weak peristalsis of the gastrointestinal tract, dilatation and pneumatization of the intestinal tract, obstructive changes and multiple abscesses in the abdominopelvic cavity are typical ultrasound manifestations of severe appendicitis, including periappendiceal abscesses.