PANCREAS

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Normal anatomy & appearance

• On ultrasound, the pancreas is located in the upper abdomen between the stomach (anteriorly) and the major vessels (posteriorly). A useful landmark is the Splenic Vein, which lies posterior to the body/tail of the pancreas. 

• The normal sonographic appearance: usually homogeneous echotexture, often isoechoic to slightly hyperechoic compared to the liver, though increasing fatty infiltration with age may make it more echogenic. 

• Normal duct diameter: The main pancreatic duct (MPD) is typically ≤ 2–3 mm. In the head region the common bile duct (CBD) is also visible (normal 4 mm) when well-seen. 

Technique & scanning tips

• Patient preparation: Fasting (6+ hours) helps reduce bowel gas and improves visualization. 

• Transducer selection: Use a curved array (e.g., 3–6 MHz) appropriate for penetration; in thinner patients higher frequency may be used. 

• Approach:

  • Start high in the epigastrum, transverse orientation, locate aorta/IVC as deep landmarks, then identify splenic vein and the gland above it. 

  • To visualize the tail of the pancreas, a left inter-costal or subcostal approach using the spleen as acoustic window may be required. 

  • Sweep through head → neck → body → tail, in both transverse and longitudinal planes.

Measurements (normal reference)

• Sizes vary with age, habitus. Approximate normal values: head ≈ 35mm anterior–posterior, neck ~10-15mm, tail ~20mm (though wide variability). 

• Because pancreatic size correlates poorly with body size or age, the focus is often on morphology rather than exact measurements. 

Common pathologies & ultrasound findings

• Acute or chronic pancreatitis: gland enlargement, heterogeneity, increased echogenicity (in chronic), calcifications, duct dilatation. 

• Pancreatic cysts / pseudocysts: anechoic or complex fluid‐filled areas, often with history of pancreatitis.

• Pancreatic adenocarcinoma or mass lesions: focal hypoechoic or heterogeneous masses, duct obstruction, vascular involvement. 

• Lipomatosis/fat infiltration: increased echogenicity of the gland.

Clinical tips

• Always scan in more than one plane; a single view may miss pathology or mischaracterize.

• Use surrounding vascular landmarks (splenic vein, SMV, aorta) to reliably locate the pancreas.

• Be aware of limitations: bowel gas, patient habitus can degrade image quality.

• Document both normal and abnormal sections: size, contour, echotexture, ductal changes, calcifications.

2. Spleen

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Normal anatomy & appearance

• The spleen lies in the left upper quadrant (LUQ), typically posterior, adjacent to diaphragm, stomach, and left kidney. It is intraperitoneal. 

• On ultrasound, normal spleen: homogeneous echotexture, often slightly more echogenic than the kidney. 

• Normal size: According to measurement studies, upper limit of length ~12-15 cm in adults (varies with body size).

Technique & scanning tips

• Patient preparation: Fasting may help reduce interfering bowel gas.

• Approach: Subcostal or intercostal window in the left lateral decubitus or supine with left arm raised may improve access. The spleen can be visualized between ribs.

• To measure: Place probe longitudinally (often between ribs), align with longest axis of spleen from upper pole (near diaphragm) to lower pole. Width (medial-lateral) and thickness (anterior–posterior) can be measured. 

Measurements (normal reference)

• Length: ~11–13 cm typical in many adults; however individual variation significant. 

• Thickness: 6 cm often used as cutoff when length borderline.

Common pathologies & ultrasound findings

• Splenomegaly: enlarged spleen, rounded contour, may extend below left kidney. 

• Trauma / splenic laceration: irregular parenchymal defects, subcapsular hematoma, free fluid in splenorenal recess (“Koller’s pouch”). 

• Cysts / infarcts / abscesses: focal areas of altered echogenicity, fluid collections. 

• Accessory spleen (splenule): small extra nodules with similar echogenicity to spleen; common (≈10%)

Clinical tips

• When measuring spleen, use consistent anatomical landmarks and scan plane to compare serially.

• Assess for perisplenic fluid (especially in trauma).

• Compare echogenicity of spleen to kidney (spleen often more echogenic than left kidney) as a quick check of texture.

• Document any focal lesions, contour changes, surrounding fluid.

Summary Comparison Table