Percussion in GI System Examination — Detailed Clinical Steps

A. Patient Positioning and Preparation

1. Position: Patient supine, arms at sides, knees slightly flexed to relax the abdominal wall musculature.
2. Exposure: Abdomen fully exposed from xiphisternum to inguinal ligaments.
3. Bladder emptied before examination if possible.
4. Warm hands: Cold hands cause involuntary guarding, distorting findings.
5. Order: Always percuss before palpation — percussion-elicited tenderness guides where not to apply deep pressure first.

"The examination proceeds with auscultation followed by percussion, and it ends with light and deep palpation." — Goldman-Cecil Medicine, Abdominal Examination

B. General Survey / Orientation Percussion

1. Begin at the epigastrium (normally tympanic — gastric air bubble).
2. Percuss systematically across all nine regions or four quadrants — upper, mid, and lower abdomen.
3. Note:
   • Tympany (hollow, drum-like) = gas-filled bowel (normal over most of the abdomen)
   • Dullness (flat, thud-like) = solid organ, fluid, or feces
4. Mark any unexpected areas of dullness or tympany.
5. Note any area that elicits pain on percussion — this localizes peritoneal irritation before palpation, which is less painful than deep palpation or rebound testing.

"Initial cursory light percussion across the upper, mid, and lower abdomen is useful to denote areas of dullness and tympany as well as to elicit unanticipated areas of pain or tenderness before palpation." — Goldman-Cecil Medicine

"Percussion is extremely valuable in the detection of localized or diffuse peritonitis. Elicitation of sharp pain with gentle percussion is preferred to both deep palpation and testing for rebound tenderness, which are unnecessarily painful." — Yamada's Textbook of Gastroenterology

C. Liver Percussion (Right Upper Quadrant)

Step-by-Step:

1. Begin at the right midclavicular line (MCL), start at the level of lung resonance (around the 3rd or 4th intercostal space).
2. Percuss downward rib space by rib space.
3. The transition from lung resonance → dullness marks the upper border of the liver (normally at the 5th intercostal space in the MCL).

1. From the right iliac fossa, percuss upward along the MCL.
2. The transition from tympany (bowel) → dullness marks the lower border of the liver (normally at or just below the right costal margin).

• Measure the vertical distance between upper and lower borders of dullness.
• Normal liver span: 6–12 cm in the midclavicular line.
• Liver span < 6 cm suggests cirrhosis/hepatic atrophy.
• Liver span > 12 cm suggests hepatomegaly (congestion, fatty liver, viral hepatitis, malignancy).

"The liver is dull to percussion. Percussion of the right upper quadrant can determine the liver span, normally 6 to 12 cm in the midclavicular line. The liver span may be diminished in a patient with cirrhosis, whereas hepatomegaly is detected in hepatic congestion resulting from heart failure, nonalcoholic fatty liver disease, and cholestatic forms of cirrhosis." — Goldman-Cecil Medicine, Examination of the Abdomen

D. Spleen Percussion (Left Upper Quadrant)

Method 1 — Castell's Method (Supine — Most Common Screening Test)

1. Patient supine.
2. Percuss the lowest left intercostal space in the anterior axillary line (approximately the 8th–9th intercostal space).
3. Percuss during normal expiration → should be resonant (gastric bubble or bowel).
4. Ask patient to take a deep inspiration and hold it → percuss again at the same spot.
5. Interpretation:
   • Remains resonant on full inspiration → spleen is likely normal in size.
   • Becomes dull on full inspiration → suggests splenomegaly (spleen descends and displaces air).

"A dull percussion note on full inspiration suggests splenomegaly." — Harrison's Principles of Internal Medicine, 22nd ed.

Method 2 — Nixon's Method (Right Lateral Decubitus)

1. Patient positioned on the right side (so the spleen lies superior to the colon and stomach).
2. Percuss from the lower level of pulmonary resonance in the posterior axillary line, proceeding diagonally toward the lower midanterior costal margin.
3. The upper border of dullness is normally 6–8 cm above the costal margin.
4. Dullness > 8 cm in an adult → presumed splenomegaly.

Method 3 — Traube's Semilunar Space Percussion

1. Patient supine, left arm slightly abducted.
2. Identify Traube's space — bordered by: 6th rib (superiorly), left midaxillary line (laterally), left costal margin (inferiorly).
3. Percuss this space from medial to lateral during normal breathing.
4. Normal: resonant (tympanic) throughout.
5. Dull percussion note → suggests splenomegaly (or, less commonly, a left pleural effusion or gastric contents).

"The borders of Traube's space are the sixth rib superiorly, the left midaxillary line laterally, and the left costal margin inferiorly. A dull percussion note suggests splenomegaly." — Harrison's Principles of Internal Medicine, 22nd ed.

E. Percussion for Ascites

Step 1 — Flank Percussion (Screening)

1. Patient supine.
2. Percuss from the umbilicus laterally toward the right flank and then the left flank.
3. Tympany centrally (air-filled bowel floats) → dullness in the flanks (fluid is dependent) is the expected pattern.
4. If dullness begins unusually high in both flanks → suspect ascites.

Step 2 — Shifting Dullness Test (Most Sensitive Bedside Test)

1. Identify the transition point from tympany to dullness during supine percussion of the flank.
2. Keep your finger at that point (mark the skin).
3. Ask the patient to roll toward you (onto the side being tested).
4. Wait 30–60 seconds for fluid to redistribute.
5. Percuss the same point again.
6. Interpretation:
   • Point becomes tympanic → shifting dullness positive → ascites confirmed (the fluid shifted to the dependent side, and bowel gas moved to the now-uppermost position).
   • Remains dull → no significant free fluid.
7. Repeat on the other side to confirm.

"Shifting dullness results from movement of ascites to the most dependent portion of the abdomen. The subject should be examined in the supine position, with percussion from the midline toward the right or left flank. A change from tympany to dullness signifies a change from air to fluid... If that spot is now tympanic, shifting dullness has been detected." — Goldman-Cecil Medicine, Examination of the Abdomen

Step 3 — Fluid Wave / Fluid Thrill (Large Ascites, > 10 L)

1. Patient supine.
2. Ask the patient (or an assistant) to place the ulnar edge of one hand firmly on the midline abdomen (to dampen fat wave transmission through the abdominal wall).
3. The examiner places one hand flat on one flank.
4. The other hand taps or flicks the opposite flank sharply.
5. A transmitted fluid impulse (wave) felt by the receiving hand → positive fluid thrill → large volume ascites.

"A fluid wave can be felt by placing the medial border of one hand on the abdomen and tapping the right or left lateral abdominal walls; the resulting wave is felt by the first hand." — Goldman-Cecil Medicine

F. Percussion for Gastric Distension and Intestinal Obstruction / Ileus

1. Percuss the epigastrium — normally tympanic (gastric air bubble).
2. In gastric outlet obstruction / gastroparesis: large area of tympany with a "succussion splash" on auscultation.
3. In intestinal obstruction: widespread tympany due to air in dilated bowel loops.

"On percussion, the abdomen is resonant due to the presence of air in dilated segments of small intestine and colon." — Mulholland and Greenfield's Surgery, 7th ed., Diagnosis

G. Percussion for Bladder Distension (Suprapubic)

1. Begin percussing from the umbilicus downward toward the pubic symphysis.
2. Transition from tympany → dullness in the suprapubic region → indicates a distended bladder or pelvic mass.
3. After voiding, re-percuss: if dullness disappears → confirmed bladder retention; if it persists → pelvic mass.

H. Percussion for Peritoneal Irritation

1. Use very gentle percussion — single, light tap with one finger on the abdominal wall.
2. Sharp, localized pain with gentle percussion = peritonism (peritoneal inflammation).
3. This is preferred over rebound tenderness testing (Blumberg sign), which causes unnecessary pain and is less specific.

"For this purpose, the elicitation of sharp pain with gentle percussion is preferred to both deep palpation and testing for rebound tenderness, which are unnecessarily painful." — Yamada's Textbook of Gastroenterology

Summary Table

• Goldman-Cecil Medicine, International Edition — Abdominal Examination & Examination of the Abdomen (Liver Disease)
• Harrison's Principles of Internal Medicine, 22nd ed. (2025) — Clinical Assessment (Spleen), Ascites, Physical Examination
• Yamada's Textbook of Gastroenterology, 7th ed. — Percussion
• Mulholland and Greenfield's Surgery, 7th ed. — Diagnosis (Intestinal Obstruction)