A normal gallbladder is a small, pear-shaped sac that sits just beneath the liver on the right side of your abdomen. It typically measures about 6 to 7 centimeters long and roughly 3 centimeters wide, making it about the size of a small pear or a chicken egg. Its job is to store and concentrate bile, the digestive fluid your liver produces, then release it into your small intestine after you eat.
Shape, Color, and Physical Structure
From the outside, the gallbladder has a smooth, slightly glistening surface with a blue-green or grey-green tint. That color comes from the bile stored inside. It’s a hollow, balloon-like organ with thin, flexible walls that allow it to expand and contract as it fills with bile and empties it.
The organ has three distinct sections. The fundus is the rounded bottom tip that extends slightly beyond the edge of the liver and is the part a doctor can sometimes feel during a physical exam. The body is the main midsection, which rests in a shallow groove on the liver’s undersurface. The neck is the narrowest part, where the gallbladder tapers and connects to the cystic duct, a small tube that feeds into the larger bile duct system running to your small intestine.
Where It Sits in the Body
The gallbladder is tucked into a shallow depression on the underside of the liver’s right lobe, in the upper right portion of your abdomen. It’s closely attached to the liver surface on top and covered by a thin membrane on its lower side. From there, a network of ducts (the biliary tree) connects it to both the liver above and the small intestine below. This positioning is why gallbladder problems often produce pain in the upper right abdomen, sometimes radiating toward the right shoulder blade.
Normal Size and Dimensions
In a healthy adult, the gallbladder averages about 6.5 centimeters in length for both men and women. Width and volume, however, differ slightly between sexes. Men tend to have a mean width of about 2.9 cm and a volume around 30 milliliters, while women average closer to 2.8 cm wide with a volume around 27 milliliters. Wall thickness in a healthy gallbladder is typically 3 millimeters or less. When the wall measures above 3.5 mm, it’s a reliable indicator of disease, though this measurement is most accurate when taken after fasting.
What It Looks Like on Ultrasound
Most people searching for what a normal gallbladder looks like have either seen an ultrasound image or are about to get one. On ultrasound, a healthy gallbladder appears as a dark (nearly black), pear-shaped pocket with a bright white outline. The dark interior means the bile inside is fluid and free of stones or sludge. The bright wall should be thin and uniform, measuring no more than 3 mm. There should be no bright spots floating inside (which would suggest gallstones) and no thickening or fluid around the outside.
Fasting matters for accuracy. When you eat, especially a fatty meal, the gallbladder contracts to squeeze bile into your intestine. A study measuring gallbladder contraction found that after a fatty meal, the organ can shrink anywhere from 6% to 87% of its fasting volume, with an average contraction of about 28%. A contracted gallbladder appears smaller and its walls look thicker, which can make a normal gallbladder mimic a diseased one. That’s why imaging centers ask you to fast for at least 8 hours before an abdominal ultrasound.
Normal Variations That Aren’t Problems
Not every gallbladder looks like the textbook version, and that’s fine. Several anatomical variations are completely harmless.
- Phrygian cap: The most common variant, found in about 2% of people. The fundus folds back over the body of the gallbladder, creating a cap-like shape. It causes no symptoms and needs no treatment.
- Junctional folds: Small ridges or kinks where the body meets the neck, sometimes visible on imaging. These are normal structural features.
- Septations: Thin internal walls that partially divide the gallbladder interior. Usually incidental findings with no clinical significance.
Rarer variants include gallbladder duplication (two separate gallbladders) and diverticula (small outpouchings of the wall). These are uncommon but typically discovered by accident during imaging for something else. If a radiologist notes one of these on your report, it almost always requires nothing more than a mention.
Signs That Something Looks Abnormal
Knowing what normal looks like makes it easier to understand what stands out as abnormal. On imaging, the most common red flags include a wall thicker than 3.5 mm, bright spots inside the gallbladder that cast shadows (gallstones), a layer of sludge settling at the bottom, or fluid surrounding the organ. A gallbladder that’s distended well beyond 10 cm in length may indicate a blockage in the cystic duct preventing it from emptying.
Physically, an inflamed gallbladder loses its normal blue-green color and becomes red, swollen, and sometimes covered with a yellowish coating. In severe cases, parts of the wall can appear dark or black, indicating tissue death. These changes are visible during surgery but not something you’d ever see yourself. What you would notice are symptoms: sharp pain in the upper right abdomen after eating, nausea, or pain that lasts more than a few hours. A gallbladder that looks normal on imaging and empties properly after meals is functioning as it should.