POCUS Simplified: Gallbladder Ultrasound
Introduction
Point-of-care ultrasound (POCUS) is an important component of the evaluation of patients with right upper quadrant and epigastric abdominal pain. A systematic examination of the gallbladder can identify findings that support diagnoses such as cholelithiasis and acute cholecystitis and can identify biliary duct dilation that may suggest biliary obstruction.
The goal of the gallbladder examination is not simply to “find the gallbladder.” A complete examination should answer a series of specific clinical questions while ensuring that the entire gallbladder—including the gallbladder neck—is adequately visualized.
This chapter describes a systematic approach to gallbladder POCUS, with an emphasis on normal anatomy, image acquisition, and a reproducible scanning sequence.
Focused Clinical Questions
POCUS by it’s nature is a goal directed focused exam. When performing a gallbladder ultrasound our focus is solely the gallbladder and it is not a general scan of the abdomen. The defined questions we try to answer during the exam are contained in Figure 1.
Figure 1. Key POCUS Questions - Gallbladder
These findings should be interpreted together and within the patient's overall clinical presentation. Ultrasound findings provide evidence that may support or argue against a diagnosis; and along with other clinical data help us arrive to a diagnosis.
POCUS Geek Pearl
Don't stop scanning if you find gallstones. Finding stones answers only one question. Each subsequent finding will further support the diagnosis. The gallbladder neck, wall, surrounding tissue, and biliary system still need to be evaluated.
Equipment and Probe Selection
A low-frequency transducer is best for gallbladder imaging.
The curvilinear transducer is usually the first choice because its frequency and footprint are well suited for abdominal imaging. A phased-array transducer can also be used, particularly when access between the ribs is necessary.
Select an abdominal preset to optimize the machine settings for abdominal imaging.
Patient Positioning
Begin with the patient in the left lateral decubitus position (See Figure 2).
If the gallbladder cannot be adequately visualized, changing the patient's position or acoustic window can significantly improve visualization. A useful sequence is:
Left lateral decubitus
Intercostal approach
Supine
Right lateral decubitus
Changing position can shift bowel gas and alter the position of the gallbladder, creating a better acoustic window.
A Systematic Scanning Approach
A consistent scanning sequence will improve anatomy recognition and reduce the chance of overlooking important findings.
Step 1: Survey the Right Upper Quadrant
Begin in the epigastrium with the probe marker oriented cephalad and sweep laterally along the right costal margin. The costal margin will force the probe inferior as you move laterally.
Do not focus exclusively on the gallbladder during this initial survey. Survey the visualized liver for obvious abnormalities while locating the gallbladder. Although not part of the focused questions of the exam we want to assure that the liver echotexture and echogenicity appear normal.
The gallbladder lies inferior to the liver. The liver will be on the left side of the screen and the gallbladder will be towards the right of the screen.
The purpose of this first sweep is both to locate the gallbladder and to develop an overall impression of the right upper quadrant (See Figure 3).
Step 2: Find the Gallbladder in Long Axis
Figure 4. Image Gallery - Gallbladder Long Axis
Once the gallbladder is identified, rotate and angle the transducer until the long axis of the gallbladder is obtained.
Do not become overly concerned with maintaining a traditional probe-marker orientation. The gallbladder does not necessarily lie in a standard anatomical plane. Instead, rotate the transducer until the imaging plane follows the long axis of the gallbladder.
In the long-axis view, evaluate and save images demonstrating the:
Gallbladder fundus
Gallbladder body
Gallbladder neck
If gallstones (cholelithiasis) are present, save images demonstrating the stones and their location within the gallbladder.
POCUS Geek Pearl
Respiratory motion can make it difficult to obtain precise images of the gallbladder. Having the patient take a deep breath and briefly hold it may improve visualization and help define important structures, particularly the gallbladder neck.
The Gallbladder Neck: Don't Miss It
One of the most important parts of a gallbladder examination is deliberate visualization of the gallbladder neck (See Figure 5).
Follow the gallbladder from the fundus and body toward the neck. The neck generally courses toward the region of the portal triad, although its exact orientation varies.
Video - Acute Cholecystitis
In a normal examination, the gallbladder walls should taper toward the neck. Carefully inspect this region for an echogenic structure with posterior acoustic shadowing that
could represent an impacted stone.
Figure 5. Image Gallery - Gallbladder Neck Long Axis
Step 3: Scan the Entire Gallbladder in Short Axis
After completing the long-axis evaluation, rotate the transducer approximately 90° to obtain the short-axis view.
Begin at the gallbladder neck (see Figure 7), which you have already identified in long axis, and fan progressively through the body toward the fundus until the gallbladder completely disappears from view. This evaluates the gallbladder in a second imaging plane and decreases the likelihood of missing a stone or other focal abnormality.
Figure 7. Image Gallery - Gallbladder Neck Short Axis
If gallstones (cholelithiasis) are present, save images demonstrating the stones and their location within the gallbladder.
The anterior gallbladder wall thickness should also be measured. Ideally, this is performed in the short-axis view by measuring the anterior wall adjacent to the liver. If the wall cannot be adequately measured in short axis, it may alternatively be measured in the long-axis view.
Zooming in before placing the calipers can improve measurement accuracy by allowing more precise caliper placement (See Figure 8).
Figure 8. Image Gallery - Gallbladder Fundus Short Axis
Step 4: Evaluate for Sonographic Murphy Sign
The sonographic Murphy sign is focal maximal tenderness elicited when pressure is applied with the transducer directly over the ultrasound-localized gallbladder.
This differs from simply identifying right upper quadrant tenderness. To assess for a sonographic Murphy sign, first identify the gallbladder and then determine whether pressure directly over it reproduces the patient's maximal tenderness compared with other areas of the abdomen.
The Murphy sign can be evaluated in either long or short axis of the gallbladder fundus. Use whichever view allows you to confidently localize the gallbladder and apply direct pressure over it.
Step 5: Identifying the Common Bile Duct
The common bile duct (CBD) can be one of the most technically challenging portions of the gallbladder examination.
A useful approach is to first identify the portal vein, which can be visualized in either long or short axis. The portal vein is typically recognized by its echogenic walls.
The common bile duct typically courses anterior to the portal vein. With the transducer oriented so that anterior structures appear at the top of the ultrasound image, the common bile duct will therefore lie superior to the portal vein on the screen (See Figure 9).
Figure 9. Image Gallery - Common Bile Duct
Color Doppler can be helpful when identifying the common bile duct by distinguishing vascular structures from the duct. However, the CBD can often be identified using anatomical relationships alone.
When the structures are adequately visualized, the portal triad consists of:
Portal vein
Common bile duct
Hepatic artery
When measuring the common bile duct, place the calipers inner wall to inner wall. It may be helpful to zoom in when performing this measurement.
Importantly, ultrasound may demonstrate biliary duct dilation without directly visualizing a common bile duct stone (choledocholithiasis). Failure to visualize a stone therefore does not exclude choledocholithiasis.
POCUS Geek Pearl
If the gallbladder is visualized in long axis: Follow the gallbladder toward the neck. The neck typically points toward the portal triad. In this orientation, the portal vein is often encountered in short axis, and the gallbladder and portal vein may resemble an exclamation point.
If the gallbladder is visualized in short axis: Fan toward the gallbladder neck and continue superior. The portal vein will often come into view in long axis.
In either approach, the gallbladder neck can serve as a landmark that leads you toward the portal triad and common bile duct.
Key POCUS Questions
Key POCUS Question: Are Gallstones Present?
Gallstones typically appear as echogenic structures with posterior acoustic shadowing. Because stones may settle dependently, the entire gallbladder should be evaluated in both long and short axes as described above. Consistently performing the examination in a systematic sequence as described previously decreases the likelihood of missing gallstones or other pathology (See Figure 10a).
Figure 10a. Image Gallery - Cholelithiasis
Small stones can be more difficult to identify because they may not produce obvious posterior acoustic shadowing. Carefully evaluate the dependent portion of the gallbladder for small echogenic foci that may represent gallstones (See Figure 10b).
Patient repositioning can also help determine whether a suspected stone is mobile.
Figure 10b. Image Gallery - Numerous small gallstones, commonly referred to as gravel, demonstrate posterior acoustic shadowing.
Key POCUS Question: Is There a Stone Impacted in the Gallbladder Neck?
Particular attention should be paid to the gallbladder neck. Stones within the body or fundus may be readily apparent, while a stone impacted in the gallbladder neck can be considerably more difficult to visualize (See Figure 11).
Figure 11. - Image Gallery White arrow - Impacted stone in neck; Red Arrow - Fundal stones
POCUS Geek Pearl
When evaluating the gallbladder neck, make sure you can see the walls narrow and taper toward one another. If the neck remains rounded, you may not have visualized it in its entirety.
To identify an occult stone impacted in the gallbladder neck, carefully trace the posterior echogenic wall toward the neck. An abrupt disruption or loss of the posterior wall may represent acoustic shadowing from an impacted stone.
Key POCUS Question: Is the Anterior Gallbladder Wall Thickened?
An anterior gallbladder wall thickness of 3 mm or less is considered normal, while greater than 3 mm is considered thickened (See Figure 12).
Figure 12. Image Gallery - Anterior GB Wall Thickened
Gallbladder wall thickening is not specific to acute cholecystitis and should be interpreted in the context of the remainder of the ultrasound examination and the patient's clinical presentation.
Anterior gallbladder wall thickness pitfalls:
The fluid-filled gallbladder produces increased through-transmission, which can make the posterior wall appear more prominent. Measuring the anterior wall provides a more reliable assessment.
Gallbladder wall thickening is nonspecific and may also occur with systemic edema, heart failure, cirrhosis, hepatitis, renal failure, hypoalbuminemia, pancreatitis, and a contracted non-fasting gallbladder.
Consider whether the gallbladder is contracted. A non-fasting, contracted gallbladder may have an apparently thickened wall and should be interpreted cautiously.
Key POCUS Question: Is there Pericholecystic Fluid?
Examine the tissues surrounding the gallbladder for pericholecystic fluid. This typically appears as a thin anechoic layer or collection adjacent to the gallbladder wall.
Fluid adjacent to the gallbladder can support the diagnosis of acute cholecystitis when present with other compatible findings. As with gallbladder wall thickening, this finding should not be interpreted in isolation (See Figure 13).
Figure 13. Image Gallery - Pericholecystic Fluid
Key POCUS Question: Is there a Sonographic Murphy Sign?
As described in Step 4 above, the sonographic Murphy sign is assessed by positioning the gallbladder directly beneath the transducer and applying pressure with the probe. If this reproduces the patient's maximal tenderness compared with other areas of the abdomen, the sonographic Murphy sign is considered positive.
Key POCUS Question: Is the Common Bile Duct Dilated?
As described in Step 5 above, an attempt should be made to visualize and measure the common bile duct. In an adult with a gallbladder, a CBD diameter of 6 mm or less is generally considered nondilated, while a diameter greater than 6 mm is considered dilated.
However, CBD diameter should not be interpreted as a simple positive or negative test for choledocholithiasis. A patient with a CBD measuring less than 6 mm may still have a common bile duct stone, particularly early in the course of obstruction.
For this reason, the CBD measurement should always be interpreted in the context of the patient's clinical presentation, laboratory findings, and the remainder of the ultrasound examination (See Figure 14).
Figure 14. Image Gallery - Dilated Common Bile Duct
POCUS Geek Pearl
A CBD measuring 6 mm or less is generally considered nondilated in an adult with an intact gallbladder, although diameter tends to increase with age. Younger patients typically have smaller ducts, so a measurement near this upper limit deserves attention when symptoms and laboratory findings suggest obstruction.
A nondilated CBD does not exclude choledocholithiasis, and a dilated CBD does not confirm it. Interpret the measurement alongside the patient’s clinical presentation, laboratory results, and remaining ultrasound findings. https://pmc.ncbi.nlm.nih.gov/articles/PMC4697124/figure/F4/
One Additional Finding: Gallbladder Distention
Although not one of our primary POCUS questions, gallbladder distention is another finding that can support the diagnosis of acute cholecystitis. A gallbladder measuring greater than 10 cm in length or 4–5 cm in transverse diameter is generally considered distended.
However, gallbladder distention is not specific to acute cholecystitis and may occur for other reasons, such as prolonged fasting. Additionally, the absence of gallbladder distention does not exclude acute cholecystitis.
As with other sonographic findings, gallbladder distention should be considered alongside the patient's clinical presentation and the remainder of the ultrasound examination.
A systematic approach to gallbladder POCUS helps ensure that important findings are not overlooked. Remember, identifying gallstones is only one part of the examination. Carefully evaluate the gallbladder neck, wall, surrounding tissues, and common bile duct to develop a more complete picture. No single ultrasound finding should be interpreted in isolation. Instead, combine your ultrasound findings with the patient's clinical presentation and laboratory results to guide your diagnosis and management.
POCUS Geek Pearl
A good gallbladder exam doesn't end when you find a stone. It ends when you've systematically evaluated the gallbladder and answered the clinical questions that matter.
Gallbladder Exam: Views to Archive
Gallbladder Long Axis - Demonstrated the gallbladder fundus and body
Gallbladder Neck Long Axis
Gallbladder Neck Short Axis
Gallbladder Fundus Short Axis
Anterior Gallbladder Wall - Measured in a zoomed image
Portal Vein and CBD
CBD Measured - Measured in a zoomed image
Optional:
Liver - To demonstrate echotexture
Core Competencies Covered in this Chapter by Specialty
AEMUS Fellowship - Core Content (Adhikari)
1.1.7.1 Hepatobiliary
1.1.7.1 Basic (Hepatobiliary)
1.1.7.1.1 Cholelithiasis
1.1.7.1.2 Cholecystitis
1.1.7.1.3 Choledocholithiasis
1.1.7.1.1 Gallbladder and biliary tree
1.1.7.2.1.1 Ductal Assessment
Emergency Medicine Residency - (Haidar)
Biliary: normal anatomy
Identifies liver
Identifies gallbladder in long axis
Identifies gallbladder in short axis
Identifies portal triad
Identifies portal vein
Identifies hepatic artery
Identifies common bile duct
Biliary: pathology
Gallstones
Identifies gallstones
Identifies gallstone characteristics of echogenicity, shadowing,
and mobility
Cholecystitis
Identifies pericholecystic fluid
Identifies increase size of gallbladder wall
Measures anterior gallbladder wall in short axis
Identifies sonographic Murphy's sign
Choledocholithiasis/cholangitis
Measures common bile duct
Family Medicine Residency (AAFP)
Biliary/abdominal
a. Biliary/abdominal basic ultrasound skills
i. Assess for symptomatic cholelithiasis: Identify presence of
gallstone versus polyp or artifact
ii. Assess for acute cholecystitis: Presence of stones, sonographic
Murphy sign, anterior gallbladder wall thickening, and
pericholecystic fluid
iii. Assess for common bile obstruction: Choledocholithiasis – measure
common bile duct (CBD) diameter
Internal Medicine Residency (LoPresti)
Gallbladder/Biliary
Gallbladder (Long Axis)
Gallbladder (Short Axis)
Portal Vein
Cholelithiasis
Sonographic Murphy Sign
Cholecystitis
Liver
Liver
Portal Vein
References
Lucius C, Braden B, Jenssen C, Möller K, Sienz M, Zervides C, Essig MW, Dietrich CF. Ultrasound of the Gallbladder-An Update on Measurements, Reference Values, Variants and Frequent Pathologies: A Scoping Review. Life (Basel). 2025 Jun 11;15(6):941. doi: 10.3390/life15060941. PMID: 40566593; PMCID: PMC12193774.
Jones MW, Santos G, Patel PJ. Acute Cholecystitis. [Updated 2025 Jul 6]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459171/
Adhikari S, Leo M, Liu R, Johnston M, Keehbauch J, Barton M, Kendall J. The 2023 Core Content of advanced emergency medicine ultrasonography. J Am Coll Emerg Physicians Open. 2023 Aug 9;4(4):e13015. doi: 10.1002/emp2.13015. PMID: 37564703; PMCID: PMC10411060.
Haidar DA, Peterson WJ, Minges PG, Carnell J, Nomura JT, Bailitz J, Boyd JS, Leo MM, Liu EL, Duanmu Y, Acuña J, Kessler R, Elegante MF, Nelson M, Liu RB, Lewiss RE, Nagdev A, Huang RD. A consensus list of ultrasound competencies for graduating emergency medicine residents. AEM Educ Train. 2022 Nov 21;6(6):e10817. doi: 10.1002/aet2.10817. PMID: 36425790; PMCID: PMC9677397.
American Academy of Family Physicians. (n.d.). Recommended curriculum guidelines for family medicine residents: Point-of-care ultrasound (AAFP Reprint No. 290D). https://www.aafp.org/assets/image/upload/v1766525730/xhyqrsqzxp94la29rj8w.pdf
LoPresti CM, Murray KJ, Dancel R, Baston C, Boesch B, Brennan D, Dallas AP, Dversdal R, Flynn T, Sadud RAF, Jensen TP, Mathews BK, Soni NJ, Zhang K, Tierney DM. Internal Medicine Residency Point-of-Care Ultrasound (POCUS) Consensus Recommendations for Core Indications and Applications. Am J Med. 2025 Dec;138(12):1705-1715.e23. doi: 10.1016/j.amjmed.2025.05.033. Epub 2025 Jun 10. PMID: 40505711.
Peng R, Zhang L, Zhang XM, Chen TW, Yang L, Huang XH, Zhang ZM. Common bile duct diameter in an asymptomatic population: A magnetic resonance imaging study. World J Radiol. 2015 Dec 28;7(12):501-8. doi: 10.4329/wjr.v7.i12.501. PMID: 26753065; PMCID: PMC4697124.
Comments