may not be possible, being alert to the possibility
of atelectasis allows medical evaluation and inter-
vention before complications such as infection or
PNEUMONIAestablish themselves.
See also CYSTIC FIBROSIS AND THE LUNGS; LUNG CAN-
CER; SMOKING AND PULMONARY DISEASE; SURGERY BENE-
FIT AND RISK ASSESSMENT.
auscultationThe diagnostic procedure of listening
to the LUNGSusing a STETHOSCOPEheld to various
placements on the chest and back. Auscultation
allows the doctor to hear normal and abnormal
BREATH SOUNDS, the noises of air flowing through
the respiratory tract. The doctor typically listens to
the same location for each lung, to compare the
sounds, and moves in a side-to-side pattern first
across the chest from the apex to base (top to bot-
tom) of each lung and then a similar pattern on
the back. When conducting a pulmonary exami-
nation, the doctor also listens with the stethoscope
placed over the TRACHEAat the throat.
There are four normal breath sounds—tracheal,
vesicular, bronchial, and bronchovesicular—all
heard upon both inhalation and exhalation. Devi-
ations in tone, loudness, frequency, and character
of the sounds help the doctor assess the perform-
ance of the lungs. Extra sounds, such as rales and
wheezes, are abnormal and signal pulmonary ail-
ments such as BRONCHITIS, ASTHMA, and PNEUMONIA.
The doctor usually listens to the HEARTas well dur-
ing auscultation, as the HEART SOUNDSprovide addi-
tional diagnostic information. The doctor uses the
diaphragm of the stethoscope to auscultate for
breath sounds and the bell of the stethoscope to
auscultate for heart sounds.
See alsoAPNEA; BREATHING; DYSPNEA; TACHYPNEA.auscultation 191