Introduction to Acoustics

Auscultation
location
Right & left
sternal border
Lower lung
quadrant
Epigastrum
Abdominal
quadrants
Scrotum
Temporal
High
Cervical Mid
Subclavian
Low
Upper lung
quadrant
Joints
Heart valves
and murmurs
Arterial bruits
Lung breath sounds
Bowel sounds
Joint crepitus
Blood pressure
cuff
Cardiac apex
Antecubital
fossa
Umbilical
Forearm
Inguinal
Thigh
Popliteal fossa
causing a longer duration of flow to fill and empty the
lungs. Thus the breath sounds are louder, longer, higherpitched
sounds compared with normal lung sounds. In
Table 21.2 Diagnosing valve disease from heart murmurs
Medical Acoustics 21.2 Medical Diagnosis; Physical Examination 843
Fig. 21.1 Auscultation sites. Arterial bruits can be heard bilaterally
indicating arterial stenoses. Heart valve sounds
and heart murmurs are primarily heard in the peristernal
intercostal spaces indicating cardiac timing, and
valve stenosis and incompetence (insufficiency or regurgitation).
Breath sounds in the lung indicate both airway
sufficiency, lung inflation, alveolar inflation and pleural
friction. Bowel sounds [21.1,2] indicate normal peristalsis;
bowel in the scrotum indicate intestinal hernia. Crepitus
on motion indicates air in the tissue, bone fracture or
joint [21.3–6] cartilage damage. Auscultation in the antecubital
fossa during blood pressure cuff deflation yields
Korotkoff sounds [21.7,8], 1 = a sharp sound each systolic
peak when the cuff pressure equals the systolic pressure indicating
the momentary separation of the artery walls and
the onset of blood flow, 2 = a loud blowing sound due to
blood turbulence, 3 = a soft thud when the artery under the
cuff is exhibiting maximum change in arterial diameter, 4 =
a soft sound indicating slight arterial deformation near diastolic
pressure, 5 = silence when the cuff pressure is below
the diastolic arterial pressure
some medical conditions, the flow dynamics may be
just right to produce coherent eddy structures, such as
one would see in a smoke stack. These signals result in
a narrow-band frequency tone.
Abnormal snapping or popping sounds may also be
present in the lung. In the normal lung, the alveoli (terminal
air sacks, 280 µm in diameter, 3 × 10 8 in lung)
are filled with air. In pneumonia, regions of alveoli are
filled with fluid, which prevents a rapid increase in size
without the introduction of a gas phase. The rapid introduction
of a gas phase when the lung is expanded
during the inspiration phase of respiration causes a tiny
snapping sound (broadband acoustic impulse) in each
alveolus; many snaps together cause the sound of rales.
Time Side Location Position
Tricuspid stenosis Diastolic Parasternal 3rd ICS Supine
Tricuspid regurgitation Systolic Peristernal 3rd ICS Supine
Pulmonic stenosis Systolic Right Superior Supine
Pulmonic regurgitation Diastolic Right Superior Seated
Mitral stenosis Diastolic Left Apex Supine
Mitral regurgitation Systolic Left Apex-Axilla Supine
Aortic stenosis Systolic Parasternal Superior Supine
Aortic regurgitation Diastolic Parasternal Superior Seated
Side parasternal = in the intercostal spaces on either side of the sternum
Location 3rd ICS = the space between the 3rd and 4th rib, Erb’s point
Position seated = Seated, leaning forward, breath in expiration
Part F 21.2