Abdominal Percussion

Abdominal percussion is a non-invasive procedure that helps assess the presence of gas, fluid, and solid masses in the abdomen, and can provide information in the prehospital environment where advanced diagnostic tools are not available, such as ultrasounds.

Percussion can help assist in the identification of some conditions such as bowl obstruction, organomegaly (enlarged organs) and ascites (fluid accumulation). Findings from abdominal percussion can prompt early communication to hospitals when these conditions are suspected, which can help improve patient outcomes.

In the prehospital environment, the application of percussion may be limited due to environmental factors – however, this should not deter you from carrying out this assessment.

Abdominal Region

The abdomen contains many vital organs, including the stomach, liver, pancreas, intestines, kidneys, and spleen. It plays a crucial role in digestion, metabolism, and other bodily functions.

Diagnosing conditions affecting the abdominal region is difficult in the prehospital environment due to the vast number of organs situated in this region and the limited diagnostic tools.

The abdominal region can either be split into 4 or 9 quadrants as imaged below.

Percussion Technique

For abdominal assessments the patient should lie supine (on their back) with their arms at their sides and legs slightly bent to relax the abdominal muscles.

Correct technique when percussing is essential to generate effective notes.

1. Place your non-dominant hand over the general region you would like to percuss while hyperextending the middle finger and placing it over the specific percussion area.
2. With the dominant hand’s middle finger, tap the middle phalanx of the hand above in a quick, sharp motion. The movement should come from the wrist rather than the elbow or upper arm.

“Fingernails should be kept short on the dominant tapping hand as to not hurt yourself when striking the non-dominant hand.”

Sounds Heard In Abdominal Percussion

Percussion can assess organs as deep as 3 inches. As percussion is carried out around the abdominal region, you’ll hear different sounds.

Tympany

A high-pitched, drum-like sound typically heard over areas filled with gas, such as the stomach and intestines. Tympany is the predominant sound in the abdomen due to the presence of gas in the gastrointestinal tract.

Dullness

A flat, thud-like sound heard over solid organs like the liver or spleen, or over areas with fluid accumulation. Dullness can indicate the presence of an underlying mass or fluid.

Resonance

A sound that is between tympany and dullness, which may be heard over a mix of solid and hollow organs.

General Abdominal Percussion

A general percussion of the abdominal region should take place first. This involves percussion the 4 or 9 abdominal regions. It is important to have a good understanding of organ location in the abdominal region to detect if the percussion findings are normal.

Start from the right lower quadrant and move around the abdominal region in a clockwise direction.

The two sounds you are likely to hear while carrying out general abdominal percussion will be tympany (hallow air filled organs such as stomach/bowel) and dullness (solid orangs such as the liver or faeces filled intestine).

Assessing Organs

There are two organs to assess when carrying out abdominal percussion: liver and spleen.

Assessing the liver size can give an indication about the health and function of the liver. Hepatomegaly (enlarged liver) can indicate a range of conditions such as hepatitis, cirrhosis and fatty liver disease. Other conditions such as heart failure and metabolic disorders can also cause hepatomegaly.

To assess for hepatomegaly

1. Start percussing in the right midclavicular line from around the 3rd intercostal space and move downwards. You should notice a sound change from resonant (lung) to dull (liver). Mark this change which represents the upper border of the liver
2. Start below the umbilicus again in the right midclavicular line and percuss upwards until the sound changes from tympanic (intestine) to dull (liver). Mark this region which represents the lower border of the liver.
3. Measure the distance between the two lines.

A normal liver size is approximately 6-12cm.

The spleen is located posteriorly, below the left midaxillary line. The enlargement of the spleen (splenomegaly) may indicate infections, liver disease, blood disorders or some cancers. Assessing spleen size due to its location however is possible with the following techniques (Traube’s Space and Castell’s Sign).

Traube’s Space

Traube’s space is a specific area used to help identify an enlarged spleen.

It is bordered by the 6th rib (upper boundary), the midaxillary line, and the 9th rib at the anterior axillary line (lower boundary).

When percussing in this space, the sound should normally be tympanic (indicating the presence of air).

If the sound is dull, this may indicate enlarged spleen.

Castell’s Sign

Identify the anterior axillary line and locate the lowest possible rib space.

Percuss in this space initially; the sound should be tympanic.

Ask the patient to take a deep breath in. During deep inhalation, the spleen moves towards the anterior axillary line.

If the sound remains tympanic during the breath, the spleen is likely of normal size.

If the sound changes to dullness, this indicates a positive Castell’s sign, suggesting an enlarged spleen.

Detecting Fluid (Ascites)

Ascites is the accumulation of fluid in the peritoneal cavity. Percussion helps in identifying and assessing the extent of fluid.

To assess for ascites:

1. Starting with the patient supine, with you on the patient’s right, percuss from the umbilicus towards the bed and the right flank. Once the tone becomes dull make a mark.
2. Then turn the patient on to their right side and wait for 30 secs. Then begin to percuss above the umbilicus and work your way towards the umbilicus and the original line you drew.
3. If the tone goes from tympany to dullness before you reach your original line, the patient may have ascites.

Key Points

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