1. Positioning

1. Make sure the patient is undressed down to the waist.
2. Position the patient on the examination table at a 30- to 45-degree angle and approach from the right side. Examining the posterior of the lung requires the patient to be leaning forward or sitting on the edge of the bed.

2. Percussion

1. Percuss both posteriorly and anteriorly, starting on the back.
2. Place non-dominant hand with middle finger (pleximeter finger) pressed and hyperextended firmly on the patient's right or left mid-back area (lower levels of lungs posteriorly). The firmer the finger is pressed to the chest wall, the louder the percussion note tends to be.
3. Make sure the other fingers and palm are not pressed against the patient's chest.
4. Use the tip of the middle finger (plexor finger) of the dominant hand to tap firmly on the top third (middle or distal phalanx) of the pleximeter finger of the non-dominant hand at least twice (it is advisable to keep fingernails short). The sound should be hollow, representing an air-filled lung.
5. Repeat the percussion at four and five levels, comparing each lung level side by side, working up to the chest wall, starting at the inferior lung borders. On expiration, the lower border of the lungs is at the level of the sixth rib at the midclavicular line and the eighth rib at the midaxiallary line anteriorly, approximately at the level of the T10 spinous process posteriorly.
6. Percuss anteriorly and posteriorly, placing the finger on the chest in the intercostal spaces.
7. Appreciate the quality of percussion sounds. The normal findings on the chest percussion are:
   1. Resonant percussion note: heard over a normal air-filled lung.
   2. Dull percussion note (the sound heard over solid tissues): over the liver in the right lower anterior chest and over the heart in the left anterior chest. When percussion of the lungs elicits this sound, it is indicative of consolidation.
   3. Tympanic percussion note (a drum-like sound when percussing over hollow organs): over the Traube's space, an area overlying the gastric bubble and bordered by the sixth rib, anterior axillary line, and left costal margin. Left pleural effusion produces a dull percussion sound over Traube's space.
8. Note the presence of pathological percussion sounds. A "stony dull" or flat percussion note sounds duller than the "standard" dull sound. It resembles the percussion note heard over the thigh and is indicative of a pleural effusion. A hyper-resonant percussion note is a pathological percussion sound indicative of hyper-inflated lungs from advanced COPD, emphysema, or a pneumothorax.

3. Auscultation

1. Position the patient: ask the patient to lean forward or sit upright in order to examine posteriorly. Asking the patient to fold arms or place hands on opposing shoulders also helps to get maximal exposure to the lung fields.
2. Place the diaphragm of the stethoscope on the patient's chest, and ask the patient to take deep breaths in and out through the mouth.
3. Auscultate at five levels posteriorly and anteriorly, comparing side by side.
4. Normal breath sounds are called vesicular breath sounds, which are low-pitched sounds louder on inspiration and softer on expiration. They should be symmetrical posteriorly.
5. Note the presence and location of abnormal (adventitious) extra breath sounds, such as crackles, wheezing, rhonchi, stridor, or pleural friction rub (Table 1).
6. Note the following characteristics of any abnormal breath sounds (if present): loudness, quality, duration, and whether they occur during inspiration or expiration (i.e., timing in the respiratory cycle). Many abnormal breath sounds are best heard after asking the patient to cough.
7. Assess for bronchophony, an increased sound transmission over the consolidated lung, when asking the patient to say "99" or "1-2-1." Egophony is when an "E" sound changes to an "A" over consolidated lung.
8. Assess for whispering pectoriloquy. While auscultating with the stethoscope, ask the patient to whisper "99" or "1-2-1." In the consolidated lung, the sound will actually be heard better and more clearly with the stethoscope.

Table 1. A table summarizing potential findings during auscultation of the lungs.