Longitudinal Scanning of the Gallbladder from the Right Subcostal Margin

Longitudinal gallbladder section • Right subcostal approach

Scanning Method

The patient should preferably be fasted for 8–12 hours and examined initially in the supine position. Place the ultrasound probe longitudinally below the right subcostal margin in the right upper quadrant. Direct the probe toward the right shoulder and adjust the probe angle to obtain a longitudinal section of the gallbladder. The gallbladder should be demonstrated within the gallbladder fossa, preferably showing the fundus, body, neck, lumen, and gallbladder wall. Adjust depth, gain, focal zone, and probe pressure to obtain optimal visualization.

Key scanning point: Begin from the right subcostal margin with the probe oriented longitudinally. Identify the gallbladder as an anechoic fluid-filled structure and follow it from the fundus through the body toward the neck. Optimize the scanning plane to demonstrate the gallbladder in its true long axis.

Ultrasound Image

Figure 1.1: Longitudinal section of the gallbladder from the right subcostal approach. The gallbladder should be assessed for its fundus, body, neck, lumen, wall, and relationship with the adjacent liver.

Anatomical / Scanning Diagram

Figure 1.2: Diagram demonstrating the right subcostal probe orientation, longitudinal scanning plane, gallbladder, liver, and relevant biliary and adjacent anatomical landmarks.

Section Structure

The principal structures demonstrated in this plane are the gallbladder (GB), including the fundus, body, neck, lumen, and wall, together with the adjacent right lobe of the liver (RL). Depending on the scanning plane, the cystic duct, common hepatic duct (CHD), common bile duct (CBD), portal vein (PV), and adjacent bowel may also be visualized.

Structures to identify

• Right lobe of the liver (RL)
• Gallbladder (GB)
• Gallbladder fundus
• Gallbladder body
• Gallbladder neck
• Gallbladder lumen
• Gallbladder wall
• Cystic duct when visualized
• Common hepatic duct (CHD)
• Common bile duct (CBD) when visualized
• Portal vein (PV)
• Adjacent duodenum / bowel

Abbreviations Used in the Figure

Abbreviation	Full form	Identification
GB	Gallbladder	Fluid-filled biliary organ located within the gallbladder fossa.
F	Fundus	Rounded distal portion of the gallbladder.
B	Body	Main central portion of the gallbladder.
N	Neck	Narrow proximal portion leading toward the cystic duct.
RL	Right Lobe of Liver	Adjacent hepatic parenchyma surrounding the gallbladder fossa.
CHD	Common Hepatic Duct	Extrahepatic biliary structure formed by the right and left hepatic ducts.
CBD	Common Bile Duct	Extrahepatic bile duct when adequately visualized.
PV	Portal Vein	Important vascular landmark adjacent to the biliary structures.

Measuring Method and Normal

When clinically indicated, assess the gallbladder in both longitudinal and transverse planes. Evaluate the gallbladder length, width, wall thickness, lumen, contents, and overall morphology. Measurements should be obtained in an optimized plane with appropriate patient preparation and with the gallbladder adequately visualized.

Measurement	Caliper method	Reference / interpretation
Gallbladder length	Measure the maximum longitudinal dimension from the fundus toward the neck along the long axis.	Document the measurement together with the degree of gallbladder distension and sonographic appearance.
Gallbladder width	Measure the maximum transverse dimension perpendicular to the long axis.	Interpret in relation to gallbladder distension and the clinical setting.
Gallbladder wall thickness	Measure a clearly visualized wall segment with the ultrasound beam perpendicular to the wall whenever possible.	Document the measurement and assess whether thickening is focal or diffuse.

Measurement note: Ensure the gallbladder is adequately visualized before measuring. Avoid oblique measurements and avoid including adjacent liver, pericholecystic fluid, or intraluminal material in the wall measurement.

The Clinical Application Value

This plane provides a useful longitudinal view of the gallbladder from the right subcostal margin. It permits assessment of the fundus, body, neck, lumen, wall, and adjacent right hepatic lobe. The view is useful for evaluating gallbladder distension, luminal contents, calculi, sludge, wall abnormalities, and focal lesions.

• Demonstration of the gallbladder in longitudinal section.
• Identification of the fundus, body, and neck.
• Assessment of gallbladder wall thickness and regularity.
• Assessment of the gallbladder lumen for stones and sludge.
• Evaluation of posterior acoustic shadowing associated with calculi.
• Assessment of gallbladder distension.
• Evaluation for focal wall lesions or intraluminal abnormalities.
• Assessment for pericholecystic fluid.
• Assessment of the adjacent right hepatic lobe.
• Evaluation of the visualized biliary ducts.

Quick Scanning Checklist

1	Fast the patient for 8–12 hours when appropriate.
2	Position the patient supine initially.
3	Place the probe below the right subcostal margin.
4	Orient the probe longitudinally along the gallbladder long axis.
5	Identify the gallbladder within the gallbladder fossa.
6	Follow the gallbladder from fundus through body toward the neck.
7	Optimize depth, gain, focal zone, and probe pressure.
8	Assess the lumen for stones, sludge, and other intraluminal contents.
9	Assess gallbladder wall thickness, contour, and regularity.
10	Assess the adjacent liver, biliary ducts, and pericholecystic region for abnormalities.

Diagnostic Pathology

The longitudinal right subcostal view of the gallbladder can assist in identifying gallbladder, biliary, hepatic, and adjacent upper abdominal abnormalities. Evaluate the GB, fundus, body, neck, wall, lumen, right hepatic lobe, and visualized biliary structures for abnormal findings.

Key Sonographic Findings

• Gallbladder distension: Increased gallbladder distension or enlargement in the appropriate clinical context.
• Cholelithiasis: Echogenic intraluminal focus or foci with posterior acoustic shadowing and/or mobility when demonstrated.
• Gallbladder sludge: Low-level dependent echoes within the gallbladder lumen that generally do not produce clean posterior acoustic shadowing.
• Gallbladder wall thickening: Increased gallbladder wall thickness requiring correlation with gallbladder distension and other sonographic findings.
• Gallbladder inflammatory changes: Wall thickening, distension, pericholecystic fluid, tenderness during scanning, or an impacted calculus may be seen in the appropriate clinical setting.
• Impacted neck calculus: Calculus located near the gallbladder neck or cystic duct region with associated obstructive findings when present.
• Gallbladder polyp: Focal non-mobile wall-based intraluminal lesion requiring assessment of size and morphology.
• Gallbladder wall irregularity: Focal or diffuse alteration in wall contour or echotexture.
• Pericholecystic fluid: Fluid surrounding the gallbladder that may accompany inflammatory or other pathological processes.
• Gallbladder mass: Focal abnormal tissue or irregular wall-based lesion differing from normal gallbladder wall or lumen contents.
• Biliary duct dilatation: Increased caliber of visualized intrahepatic or extrahepatic bile ducts requiring assessment of the biliary system.

Diagnostic note: Abnormal findings should be interpreted together with the complete abdominal ultrasound examination, clinical history, laboratory findings, and additional imaging when indicated. A single sonographic finding should not be used in isolation to establish a diagnosis.

Diagnostic Sonography • Gallbladder

Longitudinal Right Subcostal View