The appendix is on the right side of your body. It sits in the lower right portion of your abdomen, right where the small intestine connects to the large intestine. If you drew an imaginary line from your belly button to the bony point of your right hip, the appendix would be roughly halfway along that line.
Where Exactly It Sits
The appendix is a small, finger-shaped pouch that hangs off the cecum, which is the very beginning of your large intestine. It’s tucked into what doctors call the right lower quadrant of the abdomen. The classic landmark for finding it is a spot halfway between the belly button and the front of the right hip bone. This spot is so consistently reliable that it has its own name in medicine and has been used as a surgical reference point for over a century.
The appendix itself is typically about 3 to 4 inches long, though its exact angle can vary. In some people it points downward, in others it curls behind the cecum, and in others it tucks toward the pelvis. All of these positions are still on the right side.
Why This Matters for Appendicitis Pain
Knowing the appendix is on the right helps explain the signature pain pattern of appendicitis. In most people, the pain starts as a vague ache around the belly button, then over the course of several hours migrates to the lower right abdomen. That migration is one of the most recognizable clues that the appendix is inflamed.
The pain typically sharpens and becomes more localized as inflammation worsens. Pressing on the lower right abdomen and then quickly releasing often intensifies the pain, which is a sign that the tissue lining the abdominal wall has become irritated. Coughing, walking, or riding over bumps in a car can make it worse too.
When the Appendix Is on the Left
In rare cases, the appendix can be on the left side. This happens with one of two congenital conditions. The first, called situs inversus totalis, is a complete mirror-image reversal of all the organs in the chest and abdomen. It occurs in roughly 1 in 10,000 to 1 in 50,000 people. In a typical body, the intestines rotate counterclockwise during fetal development, placing the appendix on the right. In situs inversus, that rotation goes clockwise instead, putting everything on the opposite side.
The second condition is intestinal malrotation, where the gut doesn’t complete its normal rotation during development. In some types of malrotation, the cecum (and the appendix attached to it) ends up on the left side or in the middle of the abdomen rather than the lower right. Both conditions are present from birth, and many people never know they have them until imaging is done for an unrelated reason, or until something like appendicitis reveals the unusual anatomy.
A review of medical literature found only 63 reported cases of situs inversus combined with left-sided appendicitis, so the scenario is genuinely uncommon. But it’s clinically important because left-sided abdominal pain can delay the diagnosis if no one considers that the appendix might not be where expected.
How Pregnancy Shifts the Location
During pregnancy, the growing uterus pushes abdominal organs upward, and the appendix is no exception. A study tracking appendix position across trimesters found a clear pattern: as pregnancy progressed, the appendix was less and less likely to be in the lower right abdomen and more likely to be found in the upper right region.
By the third trimester, 72% of patients had the appendix in the right upper abdomen, 22% had it in the right middle region, and only 5% still had it in the lower right where it normally sits. None of the patients in the second trimester had the appendix in its usual lower right position either. This means appendicitis during pregnancy can cause pain higher up than expected, sometimes near the ribs rather than near the hip, which can make it harder to recognize.
How Imaging Confirms the Position
When there’s any uncertainty about where the appendix is, or whether it’s inflamed, imaging can pinpoint it. Ultrasound is the first choice for children and pregnant women because it avoids radiation. In experienced hands, its accuracy approaches that of a CT scan. CT scanning of the abdomen and pelvis is the most reliable tool overall, with about 94% sensitivity and 95% specificity for diagnosing appendicitis. MRI performs similarly and is a good alternative when radiation needs to be avoided.
If an initial ultrasound is unclear, either CT or MRI can follow. In one study, CT performed after an inconclusive ultrasound still achieved 91% sensitivity and 98% specificity. MRI in the same scenario reached 100% sensitivity and 96% specificity. For the vast majority of people, though, the combination of right-sided pain, a physical exam, and basic blood work is enough to identify appendicitis without any uncertainty about where the appendix is.