2 8. Percussion
Percussion involves tapping the body to elicit sounds and determining whether the sounds are appropriate for a particular organ or area of the body. Try tapping different surfaces with your fingertips and compare the sounds: a firm hard surface like a wood desk or table, a thick textbook, a window, or even a drum. As you tap these surfaces, you can hear that each surface elicits a different sound based on the object’s consistency. This concept also applies to the body.
Each body part that you percuss provides information about the consistency as well as the size and borders of the underlying structure. For example, the percussion sounds can tell you if the organ is:
- Air filled (e.g., lungs)
- Fluid filled (e.g., bladder and stomach)
- Dense (e.g., liver)
Percussion can also help reveal the presence of masses, particularly if they are close to the surface of the body.
There are three approaches to percussion, but the most widely used is indirect percussion, which is the application of a mediated force using parts of both of your hands. See Figure 1.8 demonstrating the technique of indirect percussion.
Figure 1.8: Indirect percussion technique
Indirect percussion is often used to assess the lungs and the abdomen (e.g., bowels, bladder, liver). The steps of this technique are as follows:
- Non-dominant hand: With your hand parallel to the body, place the distal interphalangeal joint of the pleximeter (middle) finger of your non-dominant hand firmly on the body region to percuss. Ensure that only your interphalangeal joint is touching the body (and not the rest of the hand) and that the finger is fully extended.
- Dominant hand: Flex (bend) the pleximeter finger of your dominant hand and with the tip of your finger, tap twice on the distal interphalangeal joint of your non dominant hand. The pleximeter finger of your dominant hand should be at a 90-degree angle to the surface of the body. The motion should be firm and quick with a very short duration. To optimize this motion, the wrist of your non-dominant hand should be relaxed and loose with your forearm parallel to the person’s body. This skill requires lots of practice, so start by practicing the technique on a table or your own leg.
As a nurse, you need to become familiar with the expected percussion sounds so that you can identify what is normal and what is abnormal. See Figure 1.9 for the expected location of percussion sounds and Table 1.2 for an explanation of the types of percussion sounds heard including resonance, hyperresonance, tympany, dullness, and flatness.
Figure 1.9: Expected location of percussion sounds
Table 1.2: Percussion sounds
|
Sound |
Body locations |
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Resonance is a low-pitched sound that is hollow in terms of sound quality with a moderate duration. |
Resonance is the normal sound heard when percussing the lungs because they are filled with air rather than dense tissue. However, it may be more of a dull or flat sound if a client has adipose tissue or a muscular chest, because this increased density modifies the sound. For example, findings may include “resonance anteriorly in all lobes of the lungs.” |
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Hyperresonance is also low-pitched but is more of a booming sound in terms of sound quality and has a longer duration than resonance. |
Hyperresonance can be a normal lung sound in small children or children with thin chest walls when percussing because of the round anatomical shape of their thorax. However, hyperresonance in older children and adults can be a cue that should alert you to the possible hyperinflation of lungs that occurs with many conditions (e.g., emphysema, pneumothorax). In this case, hyperresonance occurs because trapped air hyper-inflates the lungs over time and changes the anatomical shape of the thorax. For example, findings may include “resonance in lungs equal bilaterally” or “resonance in right lung and hyperresonance in left lung.” |
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Tympany is high-pitched and sounds like a drum in terms of quality with longer duration than resonance and hyperresonance. |
When performing percussion, tympany is normally heard over fluid-filled organs such as the stomach, bladder, and bowels. The combination of air and fluid creates a drum-like sound. However, the sound may be more dull or flat if a client has adipose tissue or muscles over the abdomen, because of the increased density. This can also occur if the bowels are full of stool or in the presence of . For example, findings may include “tympany with scattered dullness through all quadrants of the abdomen with dullness in upper portion of right upper quadrant.” |
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Dullness is a quiet thud in terms of quality with a high pitch and short duration. |
Dullness is the normal sound heard when percussing tissues that are dense in consistency, such as the liver. Dullness is typically considered an abnormal sound if elicited with percussion over the lungs or the intestines, stomach, or bladder. In this case, it could represent intestines that are filled with stool, indicating constipation, a bowel obstruction, or some sort of mass. For example, findings may include “dullness in left lower quadrant.” |
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Flatness is even more quiet than dullness with an even shorter duration and a high pitch. |
Flatness is elicited when percussing muscle and bone because they are very dense tissues and often close to the body’s surface, but these areas are usually not percussed because this does not generally provide relevant data. Hearing flatness over an area that typically elicits resonance or tympany should be a cue for you to engage in more careful examination. Although it may suggest adipose or muscular tissue, it can also indicate a mass. |
Another form of indirect percussion is used to assess the kidneys; this technique will be discussed in more detail when you learn about abdominal assessment.
Direct percussion involves an unmediated approach with the use of only one of your hands; it is used to assess pain/tenderness associated with the sinuses or assessing the newborn/infant’s lungs. The steps of this technique involve flexing the index and pleximeter fingers of your dominant hand, and directly tapping the body’s surface with the tips of these fingers at a 90-degree angle.
A third approach, tool-facilitated percussion, involves using an instrument to tap the body (e.g., a reflex hammer); this technique will be discussed in more detail when you learn about neurological assessment.
Clinical Tip
You must keep your nails trimmed short to perform indirect and direct percussion so that you can perform the technique accurately and elicit a useful sound. It takes practice to perfect the technique. Keep in mind the phrase “don’t be a woodpecker” – when percussing, just use two taps on the pleximeter finger in each location, and focus on listening for sounds. With children, it is important to engage the client and incorporate play when appropriate.
Voices of Experience
Percussion is one of the least used of all physical assessment techniques. It is a technique that is better confirmed using more accurate tests such as an X-ray. However, when such diagnostic tests are not readily available, such as in rural, remote or underdeveloped regions, percussion is an important non-invasive technique. Additionally, percussion is not effective when the client has a significant amount of adipose tissue or is very muscular, as these types of tissues modify the sounds you expect to hear.