Horseshoe dullness procedure in ascites

Horse-shoe Dullness

Clinical Percussion in Ascites

Definition: Horse-shoe dullness is a clinical percussion finding in ascites, where dullness is present in the flanks with central tympany due to floating bowel loops. The dull area forms a curved (horse-shoe shaped) pattern along the flanks.

1. Objective

To demonstrate and identify horse-shoe shaped dullness on abdominal percussion in a patient with suspected ascites.

2. Patient Preparation

➢ Explain the procedure to the patient.
➢ Obtain consent.
➢ Ask patient to lie supine with abdomen exposed from xiphisternum to pubic symphysis.
➢ Ensure patient is relaxed with arms by the side.
➢ Ensure good lighting.

3. Procedure

Horseshoe dullness

Step 1: Inspection

Look for the following signs:

➢ Distended abdomen
➢ Bulging flanks
➢ Shiny stretched skin
➢ Everted umbilicus

Step 2: Percussion

➢ Always start from the centre (around umbilicus).
➢ Percuss lightly in the midline (You will hear a resonant / tympanic sound).
➢ Move slowly towards the right flank.
➢ At some point, the sound changes from resonant → dull. Mark that point.
➢ Repeat the procedure on the left side.

Centre → Resonant

Both Flanks → Dull

↓

Forms a Horse-shoe Pattern of Dullness

4. Physiological Basis

In the presence of ascites:

➢ Free fluid collects in dependent areas (flanks). → Flanks are Dull
➢ Intestines filled with gas float centrally. → Centre is Resonant

5. Clinical Significance

This finding suggests moderate to massive ascites. It is often seen in conditions such as:

➢ Liver cirrhosis
➢ Nephrotic syndrome
➢ Malignancy
➢ Tuberculosis

6. Viva FAQ

Question	Answer
Why is the centre resonant?	Because intestines filled with gas float above the fluid.
Why are the flanks dull?	Because fluid collects in dependent areas due to gravity.
How much fluid is needed?	Around 500 mL to be detected on percussion.
What other tests confirm ascites?	Shifting dullness & Fluid thrill.

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