percussion in detail

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percussion physical examination technique chest abdomen clinical reference

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Percussion in physical examination

Percussion is the technique of tapping the body surface to produce sound and vibration. The examiner interprets the note to estimate whether tissue beneath the surface contains mostly air, fluid, or solid tissue. It is most useful in the chest and abdomen.

It should never be interpreted alone. Compare it with inspection, palpation, vocal fremitus, breath sounds, and the clinical context.

1. Principles

A percussion note varies mainly with the amount of air underneath the area tapped:

Note	Character	Usual example	Meaning
Resonant	Low-pitched, hollow, sustained	Normal lung	Normal air-filled lung
Hyperresonant	Louder, lower-pitched, booming	Overinflated lung	Excess air, such as emphysema or pneumothorax
Tympanitic	High-pitched, drum-like	Gastric air bubble, bowel	Large amount of air in a hollow viscus
Dull	Soft, short, higher-pitched	Liver, consolidated lung	Less air, more fluid or solid tissue
Stony dull / flat	Very soft or almost no resonance	Large pleural effusion, thigh	Dense tissue or large fluid collection

Normal air-containing lung is resonant. Dullness occurs when air-filled lung is replaced or covered by consolidation, collapse, pleural fluid, pleural thickening, or a superficial mass. Widespread hyperresonance can occur in emphysema; localized hyperresonance may occur with pneumothorax or a large bulla.

2. Types of percussion

A. Indirect percussion: standard clinical method

This is the method used for chest and abdominal examination.

The finger placed on the patient is the pleximeter finger.
The finger used to strike it is the plexor finger.

B. Direct percussion

The examiner taps the patient's body directly with one or more fingers.

Uses include:

Tenderness over a sinus
Renal angle tenderness
Percussion tenderness over a bone
Testing for peritoneal irritation with very gentle abdominal tapping

C. Fist percussion

A clenched fist or ulnar border of the hand is used, usually gently.

Example:

Costovertebral angle tenderness may suggest renal inflammation, obstruction, or a stone, but it is nonspecific and must be interpreted with symptoms and urinalysis.

3. Correct technique for indirect percussion

Position

Patient should be relaxed.
Expose the area adequately while preserving dignity.
For chest percussion, usually examine the patient sitting upright.
Use a quiet room and compare equivalent areas on both sides.

Hand placement

Place the distal phalanx of the middle finger of your non-dominant hand firmly on the skin.
Keep the rest of that hand and the other fingers off the body. Contact of the whole hand dampens vibration.
Put the finger in an intercostal space, not over a rib, when examining the chest.
Keep the pleximeter finger parallel to the intercostal space where possible.

Striking movement

Flex the wrist, not the elbow or shoulder.
Use the tip of the middle finger of the dominant hand to strike the distal interphalangeal joint or distal phalanx of the pleximeter finger.
Deliver a quick, sharp tap.
Immediately lift the striking finger off. Do not leave it touching the finger after impact.
Usually use two taps at each site, then move to the matching site on the other side.

Good percussion is produced by a free wrist movement, a firm pleximeter finger, and immediate withdrawal of the striking finger. The vibration felt through the finger is as informative as the sound heard.

Common technical errors

Percussing over ribs instead of intercostal spaces
Leaving the non-pleximeter fingers on the chest wall
Using the whole arm rather than a relaxed wrist flick
Striking too softly, too slowly, or repeatedly without lifting the finger
Comparing non-equivalent areas
Percussing through thick clothing
Calling every slightly different note "dull" rather than first checking technique and symmetry

4. Percussion of the chest

Aim

To compare resonance over both lungs and identify areas of altered air content.

Sequence

Anterior chest

Percuss from the clavicles downwards.
Compare right and left sides at the same level.
Avoid breast tissue where possible. In women, ask the patient to move the breast tissue rather than percussing over it.
Do not mistake normal cardiac dullness on the left anterior chest for disease.
The liver causes expected dullness over the right lower anterior chest.

Lateral chest

Percuss along the mid-axillary lines.
This is useful for detecting pleural effusion, which often collects basally.

Posterior chest

Ask the patient to sit upright, arms folded across the chest or hands on opposite shoulders. This moves the scapulae laterally.
Percuss from the apices above the scapulae down to the lower posterior lung fields.
Compare side to side in a ladder pattern.

Example sequence:

Right upper zone -> Left upper zone
Right mid zone   -> Left mid zone
Right lower zone -> Left lower zone

Do not compare an apex on one side with a base on the other.

Chest percussion findings

Finding	Likely explanation	Other findings that may support it
Normal resonance	Normal lung aeration	Normal breath sounds and expansion
Localized dullness	Lobar consolidation, collapse, pleural thickening, mass	Consolidation often has bronchial breathing and increased vocal fremitus
Stony dullness	Pleural effusion	Reduced expansion, reduced breath sounds, reduced vocal fremitus
Hyperresonance on one side	Pneumothorax, large bulla	Reduced breath sounds; in tension pneumothorax, severe respiratory compromise
Bilateral hyperresonance	Hyperinflation, commonly COPD/emphysema	Reduced breath sound intensity, prolonged expiration
Reduced diaphragmatic excursion	Hyperinflation, diaphragmatic weakness, pleural disease, abdominal distension	Interpret with imaging and respiratory examination

Important distinction: consolidation vs pleural effusion

Both may be dull to percussion.

Feature	Consolidation	Pleural effusion
Percussion	Dull	Stony dull
Breath sounds	Often bronchial	Reduced or absent
Vocal fremitus	Increased	Decreased
Vocal resonance	Increased	Decreased
Tracheal position if large	Usually central	May shift away from a massive effusion

These are patterns, not absolute rules.

Diaphragmatic excursion

This estimates diaphragmatic movement, usually posteriorly.

Percuss downward in the scapular line during quiet expiration until resonance changes to dullness. Mark this level.
Ask the patient to take and hold a deep breath.
Percuss downward again until dullness appears. Mark the second level.
The distance between the two marks is diaphragmatic excursion.
Compare both sides.

Reduced movement can occur with hyperinflation, pleural disease, lower-lobe collapse, phrenic nerve dysfunction, abdominal distension, or poor inspiratory effort.

5. Percussion of the abdomen

Why it is done

Abdominal percussion helps to identify:

Gas-filled bowel
Fluid in the peritoneal cavity
Liver enlargement
Splenic enlargement
Bladder distension
Areas of peritoneal irritation

Normally, the abdomen is predominantly tympanitic because bowel contains gas. A dull note may be normal over the liver and sometimes over a full bladder.

General method

Patient lies supine with knees slightly flexed if possible.
Percuss gently in all abdominal quadrants.
Start away from any painful area.
In a patient with abdominal pain, gentle percussion is preferable to forceful deep palpation for detecting peritoneal irritation.

Interpretation

Predominant tympany: normal gas-containing bowel, but may be increased with gaseous distension.
Generalized or flank dullness: may indicate ascites, a mass, enlarged organ, or full bladder.
Localized tympany with distension: supports gas-filled bowel.
Pain elicited by gentle percussion: may indicate peritoneal inflammation. Do not repeatedly provoke pain.

Shifting dullness for ascites

This test assesses whether abdominal dullness moves when free fluid redistributes with position.

Method

With the patient supine, percuss from the centre of the abdomen toward a flank.
Mark the point where tympany becomes dullness.
Ask the patient to turn onto the opposite side.
Wait briefly, then percuss again from the upper side toward the dependent flank.

Positive result

The line of dullness shifts toward the dependent side, supporting free intraperitoneal fluid.

Limitations

It may be absent with small-volume ascites.
It can be difficult to interpret in obesity, tense abdomen, bowel distension, or adhesions.
Bedside ultrasonography is more sensitive for small fluid volumes.

Fluid thrill

Used when there is marked ascites.

Ask the patient or an assistant to place the ulnar edge of a hand firmly on the midline of the abdomen.
Tap one flank.
Feel the opposite flank for an impulse.

The midline hand reduces transmission through the abdominal wall. A positive test supports a large volume of ascitic fluid but is not fully specific.

Liver percussion

Percussion can estimate liver span.

Midclavicular liver span

Percuss downward in the right midclavicular line from a resonant chest area to dullness. This identifies the upper border of liver dullness.
Then percuss upward from below the umbilicus toward the right costal margin until tympany becomes dullness. This identifies the lower border.
Measure the vertical distance between the two points.

A low lower border does not always mean hepatomegaly. It may reflect downward displacement, for example due to hyperinflated lungs. Interpret with palpation and imaging if needed.

Splenic percussion

The normal spleen is usually not palpable. Percussion may help screen for splenic enlargement.

Traube's space

This is the left lower anterior chest/upper abdomen region, normally tympanitic because of the gastric air bubble. Dullness can suggest splenomegaly, but can also result from pleural fluid, a full stomach, colonic contents, or body habitus.

Castell's sign

Percuss the lowest intercostal space in the left anterior axillary line during expiration and then during deep inspiration.

Normally the note remains resonant.
Development of dullness on inspiration may suggest splenomegaly.

Neither sign confirms splenomegaly. Ultrasound is used when confirmation matters.

6. Percussion in other systems

Renal angle percussion

Gentle percussion over the costovertebral angle can elicit tenderness in conditions involving the kidney, such as pyelonephritis or obstruction. It must be correlated with fever, urinary symptoms, urinalysis, and imaging where appropriate.

Sinus percussion

Direct percussion or pressure over frontal and maxillary sinuses may produce tenderness in sinus inflammation. Tenderness alone has limited specificity.

Bone percussion

Percussion tenderness over a bone may occur with fracture, local inflammation, metastasis, or infection. It is only an adjunct to examination and imaging.

Nerve percussion: Tinel sign

Tapping over an irritated or compressed peripheral nerve may reproduce tingling in the nerve distribution. For example, percussion over the median nerve at the wrist can provoke paraesthesia in carpal tunnel syndrome. It is not diagnostic by itself.

7. Safety and practical points

Avoid vigorous percussion over a painful area, suspected fracture, recent surgical site, severe osteoporosis, or unstable patient.
In severe acute breathlessness, do not delay emergency assessment or imaging to complete a detailed examination.
Unilateral hyperresonance with acute dyspnoea, hypotension, severe distress, or tracheal deviation raises concern for tension pneumothorax, which is an emergency.
Percussion findings are influenced by obesity, muscular chest wall, breast tissue, subcutaneous emphysema, dressings, and poor technique.
The most reliable approach is side-to-side comparison plus correlation with auscultation and imaging.

One-line summary

Percussion converts differences in underlying air, fluid, and tissue density into tactile and audible notes: resonant is normal lung, dull suggests fluid or solid tissue, hyperresonant suggests excess air, and tympany indicates gas in a hollow structure.

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