Percussion (medicine)
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Percussion is a method of tapping on a surface to determine the underlying structure, and is used in clinical examinations to assess the condition of the thorax or abdomen. It is one of the four methods of clinical examination, together with inspection, palpation and auscultation. It is done with the middle finger of the right hand tapping on the middle finger of the left hand, while the left palm is on the body.
There are two types of percussion: direct, which uses only one or two fingers, and indirect, which uses the middle/flexor finger. There are four types of percussion sounds: sonorous, hypersonorous, relatively dull and completely dull. A dull sound indicates the presence of a solid mass under the surface. A more sonorous sound indicates hollow, air-containing structures.
Percussion was initially used to distinguish between empty and filled barrels of liquor, and Dr. Leopold Auenbrugger introduced the technique to medicine.
[edit] Percussion of the thorax
It is used to diagnose pneumothorax, emphysema and other diseases. It can be used to access the respiratory mobility of the thorax.
[edit] Percussion of the abdomen
It is used to find whether any organ is enlarged and similar. It is based on the principle of setting tissue and spaces in between at vibration. The sound thus generated is used to determine if the tissue is healthy or pathological.
[edit] See also
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examination
Examination of the Anterior Respiratory System
Inspection [top]
Now is the time for a detailed look at the chest.
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a.Excavatum b. Carinatum
1. Look at the general shape of the chest wall. Are there any obvious deformities? Examples could include Pectus Excavatum (Funnel Chest) and Pectus Carinatum (Pigeon Chest).
1. Pectus Excavatum is where the sternum is depressed. The condition is benign and requires no treatment.
2. Pectus Carinatum is where the sternum and the costal cartilages project outwards. It can occur secondary to childhood asthma.
2. Can you see any scars? This may give an indication of previous operations or procedures.
3. Look for prominent chest veins, especially if the patient also had a raised JVP, as it can occur due to SVC obstruction.
4. Look at the chest wall movements. Are they symmetrical, i.e. the same on both sides, or is there a difference? Is there any lag or impairment of respiratory movement?
5. Look closely for evidence of recession (this may be suprasternal, intercostal or subcostal).
6. Look at the abdomen and chest wall during respiration. Does the patient breathe mainly with the diaphragm? This suggests problems with the chest wall, such as pleural pain or ankylosing spondylitis. Do they breathe mainly with the ribcage? This suggests diaphragmatic paralysis, peritonitis, or abdominal distension.
1. Paradoxical Abdominal Movements- Normally, during inspiration the diaphragm descends and the anterior abdominal wall moves outwards. If the diaphragm is paralysed, then the anterior abdominal wall will move inwards.
2. Paradoxical Chest Wall Movements- This occurs in tetraplegia, when the chest wall is paralysed. On inspiration, the diaphragm descends and leads to indrawing of the chest wall.
Palpation [top] Enlarge Picture Palpate the Trachea
1. Palpate the Trachea. The aim is to locate the trachea and verify that it is in the midline. The best way is to place the index and the middle fingers either side of the trachea and judge whether the distances between it and the sternocleidomastoids are equal on both sides. The trachea may be displaced by masses in the neck, such as an enlarged thyroid. But more importantly, the trachea gives an indication of the position of the mediastinum within the chest.
2. Chest Expansion tests if both sides of the chest move equally with respiration.
Mediastinal Displacement
Away from lesion:
. Pneumothorax
. Large Pleural Effusion
Towars Lesion:
. Collapsed Lung
. Localised Fibrosis
The best technique is to hook your fingers as far around the chest as possible and bring the thumbs together, but they should not be parallel with each other. The thumbs should be off the chest wall and, thus, free to move. Ask the patient to breath in, and watch your thumbs as they move apart. Look for the symmetry of motion between the two sides. This is a technique that some people find difficult on their first few attempts, but once they have seen the correct technique and practiced it themselves, they will find it easier to perform.
Watch a video of chest expansion (2.41MB)
Reduced Chest Expansion
Unilateral. This implies that air cannot enter the affected side. Causes include:
. Pneumothorax
. Pleural Effusion
. Pneumonia
. Lung Collapse
Bilateral Reduction may occur, but it is hard to detect clinically.
3. Feel for Tactile Vocal Fremitus. Fremitus refers to the palpable vibrations that are transmitted through the lungs to the chest wall when the patient speaks. It is best detected using either the ulnar border or the ball of the hand (the bony part at the base of the fingers). The patient should be asked to say '99'. This is chosen because it is usually said with a significant amount of bass in the voice. If the Fremitus is faint, then ask the patient to speak more loudly or in a deeper voice. Fremitus should be felt for in 3 different parts on each side of the chest. Compare the right and left sides at each step. It is recommended that one hand be used, feeling one area at a time, especially initially, in order to learn the feel of Fremitus. Some clinicians also feel it is more accurate. However, two hands may be used together, comparing each side simultaneously. This may facilitate the detection of differences. An added bonus is that it is quicker than using one hand.
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Right Left Fremitus Sites
4. Palpate the Axillary Lymph nodes. The idea is to feel all the 'walls' of the axilla: the superior, medial, lateral and posterior. Use your left hand to palpate the patient's right axilla and use your right hand to palpate the patient's left axilla. It should be noted that lung disease rarely involves the Axillary lymph nodes.
Percussion [top]
The purpose of percussion in the respiratory examination is to detect whether the underlying lung tissues are air filled, fluid filled, or solid. A sound technique is essential to percuss properly.
Percussion
1. Hyperextend the middle finger of the left hand. This finger is known as the pleximeter finger.
2. Place it on the chest, running in the space between two adjacent ribs. It is important that the pleximeter finger is placed flat against the chest wall.
3. Separate the fingers as wide as possible and make sure the thumb, the index, ring and little fingers are not touching the chest.
4. The right middle finger (the plexor finger) is used to strike the pleximeter finger. It is important that the tip of the plexor finger (and not the finger pad) is used to strike the DIP joint of the pleximeter finger. Thus, short nails are highly recommended to avoid self-injury! The striking motion is a quick, sharp one, with movement happening at the level of the wrist. Following the strike, the plexor finger should be removed as quickly as possible to avoid damping the vibrations.
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Percussion Sites
5. The chest should be percussed in 5 areas on each side, again comparing the right and left sides at each step. The clavicles should be percussed prior to this. However, they should be percussed directly, without an interceding pleximeter finger. They reflect the resonance of the lung apices.
6. It is usual to strike the pleximeter finger 2 or 3 times in quick succession before pausing to move on the next area.
The lungs are normally resonant to percussion. Abnormal lungs may be: hyperresonant, dull, or stony dull. Dullness is expected over the liver and over the heart. Obese patients may show reduced resonance, but this is equal on both sides. Hyperresonant Dull Stony Dull . Pneumothorax . Emphysema
. Consolidation eg in Pneumonia . Fibrosis
. Pleural Effusion
Auscultation [top]
The purpose is to assess airflow through the lungs and, along with percussion, it helps to assess the condition of the surrounding lungs and pleural space. Ask the patient to breathe deeply through their mouth. A demonstration may be useful. Start with listening to the apices of the lung with the bell of the stethoscope. The apical breath sounds can be heard just superior to the clavicles. Then listen over the chest using the diaphragm, and then listen to the lateral part of chest. You should listen in 5 areas on each side of the chest, comparing right and left sides at each step. Enlarge Picture Enlarge Picture Enlarge Picture Apex Chest Auscultation Sites
1. Listen to the Breath Sounds. These can be vesicular, bronchovesicular or bronchial.
1. Vesicular Breath Sounds - These are soft and low-pitched sounds that are heard over most of the lungs. They are heard through inspiration and continue without pause through to expiration, but fade away about one third of the way through expiration.
2. Bronchovesicular Breath Sounds - These are slightly louder and of higher pitch than vesicular sounds. The inspiratory and expiratory sounds are about equal in length. They may be head normally in the 1st and 2nd interspaces. There may occasionally be a silent interval between the inspiratory and expiratory phases.
3. Bronchial Breath Sounds - These are loud and high-pitched sounds, whose expiratory phase lasts longer that the inspiratory phase. There is a short silence between the two components.
If bronchovesicular or bronchial sounds are heard, then you should suspect that air-filled lung has been replaced by fluid-filled or solid lung tissue.
2. Listen for any added sounds. These can be crackles, wheezes or rubs.
1. Crackles - These can be fine or coarse. Fine crackles occur in inspiration and are high-pitched sounds. You can imitate the sound by rubbing some hair between your fingers near your ear. They occur due to the 'popping' opening of small airways that were closed prematurely at the end of the previous expiration. Crackles that occur early on in inspiration reflect bronchiectasis or chronic bronchitis. If they occur later in inspiration, then they may be due to pneumonia, fibrosis or LVF. Coarse Crackles occur when there is fluid in the larger bronchi. This clears on coughing or deep breathing. You should note whether the crackles are localised or not. Typically, the crackles associated with Pulmonary Oedema and Fibrosing Alveolitis affect both lung bases equally, whereas in pneumonia and in mild bronchiectasis the crackles are localised. You should bear in mind that normal individuals, especially smokers, may have a few basal crackles. These often clear on coughing.
2. Wheezes - These are predominantly expiratory sounds that reflect localised narrowing of the airways. Asthma and Chronic bronchitis are the most common causes. Occasionally, they may occur with pulmonary oedema.
3. Pleural Rub - This occurs when inflamed surfaces of the pleura rub together. Causes include pneumonia and pulmonary embolism. They usually occur in inspiration and in expiration.
