A healthy gallbladder is a small, pear-shaped sac that sits just beneath the liver on the right side of your abdomen. It’s roughly 6 to 7 centimeters long and about 3 centimeters wide, making it close to the size of a small egg. When full of bile, it holds around 30 milliliters of fluid, though this changes throughout the day depending on when you last ate.
Shape, Size, and Color
The gallbladder has a smooth, bluish-green outer surface, a color it gets from the concentrated bile stored inside. Its pear shape tapers from a broad, rounded bottom (called the fundus) to a narrow neck at the top, where it connects to the bile duct system. The fundus peeks out just below the edge of the liver, while the rest of the organ is tucked against the liver’s underside in a shallow groove.
Men tend to have slightly larger gallbladders than women. On average, a man’s gallbladder measures about 6.5 cm long with a volume near 30 cubic centimeters, while a woman’s is about the same length but holds closer to 27 cubic centimeters. These differences are small enough that, to the naked eye, a male and female gallbladder look essentially identical.
What It Looks Like Inside
If you were to cut a gallbladder open, you’d see a soft, velvety inner lining with fine folds and ridges. These folds flatten out when the gallbladder fills with bile and become more pronounced when it contracts. The bile itself ranges from dark green to yellowish-brown, and its consistency can vary from thin and watery to thick and syrupy depending on how concentrated it has become.
The wall of a healthy gallbladder is thin, measuring less than 3 millimeters. It’s made up of layers of muscle that squeeze bile out when you eat, particularly after a fatty meal. Where the gallbladder narrows into its duct, the inner lining forms spiral folds that help regulate the flow of bile, acting like a one-way valve.
How It Changes After You Eat
The gallbladder doesn’t always look the same. Between meals, it’s plump and distended, filled with bile that the liver has been steadily producing. After you eat something fatty, hormones signal the gallbladder to contract. It can squeeze down to a fraction of its resting size, pushing bile into the small intestine to help digest fat. On an ultrasound, a recently emptied gallbladder looks smaller, with thicker-appearing walls simply because the organ has compressed. This is why imaging is typically done on a fasting stomach, so the gallbladder is full and easier to evaluate.
What It Looks Like on Ultrasound
Most people encounter their gallbladder visually for the first time on an ultrasound screen. A normal gallbladder appears as a dark, fluid-filled pear shape with a bright white outline representing the wall. The bile inside shows up black because fluid transmits sound waves easily. This clean, dark interior is what a radiologist wants to see.
When something is wrong, the picture changes. Gallstones show up as bright white spots inside the dark fluid, often casting a shadow behind them. Biliary sludge, a thick mixture of bile and tiny crystite particles, appears as a grayish layer that settles along the bottom of the gallbladder like sediment in a glass. If the gallbladder wall measures thicker than 3 millimeters or there’s fluid collecting around the outside of the organ, those are signs of inflammation.
What Gallstones Look Like
Gallstones vary dramatically in appearance. They can be as small as a grain of sand or as large as a golf ball, and a single gallbladder can contain one stone or hundreds. The two main types look quite different from each other.
Cholesterol stones are the most common type, making up about 80% of gallstones. They’re usually yellowish-green, waxy, and sometimes have a slightly greasy texture. They form when bile contains too much cholesterol, which crystallizes into sludge and eventually hardens.
Pigment stones are smaller, darker, and harder. They range from dark brown to jet black and form when bile contains excess bilirubin, a waste product from the normal breakdown of red blood cells. These are more common in people with certain blood disorders or liver conditions.
What an Inflamed Gallbladder Looks Like
A gallbladder with active inflammation looks visibly different from a healthy one. The wall swells beyond its normal 3-millimeter thickness, sometimes doubling or tripling in size. The organ itself becomes distended and tense, and the outer surface may look red, swollen, or covered with a filmy layer of inflammatory tissue. Fluid often pools around the outside.
In more severe cases, the changes are striking. A gallbladder with advanced inflammation can develop patches where the wall breaks down, losing its normal layered structure and appearing mottled or uneven. In rare cases, gas-producing bacteria can infect the gallbladder, creating tiny pockets of gas within the wall that show up on imaging as bright, sparkling spots. On a CT scan, these gas bubbles are unmistakable.
One of the more unusual transformations is “porcelain gallbladder,” where calcium deposits slowly build up in the wall over years. The wall becomes hard and brittle, and on an X-ray, the entire gallbladder lights up white like a piece of ceramic. This condition is painless on its own but is monitored because of its association with gallbladder cancer.
How a Diseased Gallbladder Differs at Surgery
Surgeons who remove gallbladders see a wide spectrum. A healthy gallbladder is soft, thin-walled, and bluish-green. A chronically inflamed one is often shrunken, scarred, and stuck to surrounding tissues by adhesions. The wall becomes thick and fibrous, sometimes so rigid that it no longer resembles its original pear shape. Instead, it looks like a dense, contracted lump.
Inside a chronically diseased gallbladder, the once-smooth lining may be roughened, ulcerated, or studded with yellowish nodules of fatty inflammatory tissue. The bile is often dark, thick, and mixed with stones or gritty sediment. In some cases, the gallbladder is so packed with stones that there’s almost no bile left inside at all.