Most of your organs are not centered in your body. The liver, gallbladder, and appendix sit on the right side, while the stomach, spleen, and most of the pancreas sit on the left. A few organs, like the heart and bladder, fall near the midline but lean slightly to one side. Knowing this basic layout helps you make sense of where pain or discomfort might be coming from.
Organs on the Right Side
The liver is the largest organ on your right side, filling most of the upper right portion of your abdomen just beneath your ribs. It weighs about three pounds in most adults and extends slightly past the midline, but its bulk is firmly on the right. Tucked underneath the liver is the gallbladder, a small pouch that stores bile used to digest fats. The head of the pancreas also sits on the right, nestled into the C-shaped curve of the duodenum (the first segment of your small intestine).
Lower down on the right, in the area between your hip bone and belly button, you’ll find the appendix. It’s attached to the cecum, the starting portion of the large intestine. The classic spot for appendix pain is a point roughly one-third of the way along an imaginary line drawn from your right hip bone to your navel. The right kidney also sits in the back of the abdomen on this side, slightly lower than the left kidney because the liver above it pushes it down.
Organs on the Left Side
Your stomach sits in the upper left abdomen, curving from just below the left ribs toward the center of your body. Behind and slightly below the stomach is the spleen, an organ about the size of your fist that filters blood and supports your immune system. The body and tail of the pancreas extend from the midline to the left, with the tail reaching almost to the spleen.
The left kidney sits slightly higher than the right, typically level with the lowest ribs in your back. Both kidneys span about three vertebrae in length, but the left one sits a bit higher because there’s no large organ like the liver pressing down on it from above. The descending colon, the section of large intestine that carries waste downward, runs along the left side of your abdomen. In the lower left, the sigmoid colon makes its final S-shaped turn before connecting to the rectum.
Organs Near the Midline
The heart sits just left of center in your chest, angled so that roughly two-thirds of its mass is on the left side. This is why you feel your heartbeat more strongly on the left. The esophagus runs straight down the center of your chest before meeting the stomach on the left.
The bladder sits low and centered in the pelvis, directly behind the pubic bone. The uterus, in women, sits just above and behind the bladder, also along the midline. The abdominal aorta, the body’s largest artery, runs down the center of the abdomen along the spine before splitting into two branches near the pelvis, one heading to each leg.
Your small intestine fills much of the central abdomen, coiling in loops that don’t favor one side over the other. The transverse colon, which connects the right and left sides of the large intestine, runs horizontally across the upper abdomen just below the stomach.
The Four Abdominal Quadrants
Doctors divide the abdomen into four sections using two imaginary lines: one vertical through the belly button and one horizontal across it. This creates a simple grid that helps pinpoint where symptoms are coming from.
- Right upper quadrant: liver, gallbladder, head of the pancreas, right kidney, part of the colon, and the duodenum
- Left upper quadrant: stomach, spleen, tail of the pancreas, left kidney, and the splenic flexure of the colon
- Right lower quadrant: appendix, cecum, ascending colon, right ovary and fallopian tube (in women), and part of the small intestine
- Left lower quadrant: descending and sigmoid colon, left ovary and fallopian tube (in women), and part of the small intestine
Pain in the right upper quadrant, for example, often points to gallbladder or liver issues. Sharp pain in the right lower quadrant is a hallmark of appendicitis. Left upper quadrant pain can involve the spleen or stomach, while left lower quadrant discomfort often relates to the colon.
Why One Kidney Sits Lower
Your kidneys are roughly symmetrical, but they aren’t at exactly the same height. The right kidney typically sits a half-vertebra to a full vertebra lower than the left. The reason is straightforward: the liver, which is large and heavy, occupies the space directly above the right kidney and pushes it downward. Both kidneys extend from roughly the level of the lowest rib to the middle of the lower back, sitting behind the other abdominal organs against the back wall of the abdomen.
Paired Organs and Reproductive Anatomy
Several organs come in pairs, with one on each side. The lungs, kidneys, adrenal glands, ovaries, and fallopian tubes are all mirrored. The left lung is slightly smaller than the right to make room for the heart. Each ovary sits in the lower abdomen near the corresponding hip, connected to the uterus by a fallopian tube. In men, each testicle hangs in the scrotum, and the left testicle typically hangs slightly lower than the right, which is a normal anatomical variation rather than a sign of any problem.
When Organs Are Mirrored: Situs Inversus
In about 1 in 10,000 people, all the organs are flipped to the opposite side of the body, a condition called situs inversus totalis. The liver ends up on the left, the spleen on the right, and even the heart points to the right instead of the left. This happens during early embryonic development when the normal left-right signaling gets reversed. Most people with situs inversus live completely normal lives and may not even know about it until an imaging scan reveals the reversal. The condition is slightly more common in males, at a ratio of about 1.5 to 1. The main practical concern is that symptoms of common conditions like appendicitis show up on the unexpected side, which can initially confuse diagnosis.