Lower right abdominal pain, not appendix on ultrasound. what else is down there?

Intestine, Ovary,etc: Other organs (and their diseases) in the right lower abdomen include the small intestine (crohn's dz), large intestine (diverticulitis), fallopian tube (abscess) and ovary (ruptured cyst, torsion). While an ultrasound can be very useful for eval of the ovary, it is not reliable for diagnosing appendicitis--the gold standard is a ct of the abdomen.

Depends: If you are female could be ovarian, or in either sex a ureteral/kidney stone, hernia, constipation.