Operational Medicine 2001, Health
Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau
of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington,
An electric signal starts at the pacemaker and spreads through the heart.
Blood collects in the right atrium and is pumped
into the right ventricle, then on to the lungs. Blood returns from the lungs to
the left atrium, is pumped to the left ventricle, and then out through the
The heart is located directly behind the breast bone
(sternum) and slightly to the left.
Use the palm of your hand to feel the chest wall for the
"Point of Maximal Impulse" (PMI), which is usually found at the
apex of the heart. This apical pulse is generally located in the 5th
intercostal space, about 7-9 cm (the width of your palm) to the left of
In a noisy place, feeling for the apical pulse may be the
most examination of the heart that is possible.
The apical pulse should be regular, with a rhythmic tap,
tap, tap. If you cannot easily feel it, have the patient roll slightly to
the left, bringing the heart more into contact with the chest wall.
The apical pulse should always be closer to the
midline than the mid-clavicular line.
If lateral to the MCL, this suggests cardiac
In patients with pericardial effusions, you may not be
able to locate the apical pulse.
If you feel a vibration or buzzing sensation while
feeling the apical pulse, this suggests a heart murmur. This finding
is known as a "thrill."
"Thrills" or murmurs from other areas of the
heart are best felt through the bones of the chest wall.
Listen to the heart sounds from each of the 4 heart valves at these
In a quiet place, use a stethoscope to listen to the heart
sounds. Listening to the heart can be helped by having the patient sit up
and lean forward, or having the patient roll to the left side.
The diaphragm of the stethoscope (flat portion) is better
for hearing higher-pitched sounds. The bell (curved portion) is better for
hearing lower-pitched sounds. Press the stethoscope lightly against the
skin, just enough to form an air seal around the edges. Have the patient
exhale and then stop breathing for a moment while you listen.
Each of the four heart valves can best be heard at
specific anatomic locations on the chest wall. While there may be some
variation from patient to patient, listen to the heart beat at each of
Aortic (2nd right interspace)
Pulmonic (2nd left interspace)
Tricuspid (Lower left sternal border)
you are connected to the Internet, you can hear actual heart sounds,
normal and abnormal, at this website.
Normal Heart Sounds
Heart sounds are more complicated than a simple "lub-dub."
The first heart sound (the "lub") is called S1. It is normally a
single sound, but may be split into two distinct sounds, like a "da-dum."
While a split S1 may be associated with various heart abnormalities, some
people have a normally split S1, that fuses into a single sound when they
The second heart sound (S2), the "dub" part of
"lub-dub" is also a single sound. It, too, can be split into two
distinct sounds and that may reflect underlying heart defects, or may be
This is a mid-systolic, crescendo-decrescendo type
This is a pan-systolic type murmur.
This is a crescendo, late systolic type murmur.
This is a decrescendo, early systolic type murmur.
Normally, you will not hear any heart murmurs. Murmurs are
soft, humming or buzzing sounds, occurring between the "lub" and
the "dub." (between S1 and S2). These are called
"systolic" murmurs, occurring during cardiac systole
(contraction of the heart). There are also "diastolic" murmurs,
occurring after one "lub-dub" and before the next "lub-dub."
Murmurs are caused by turbulence in the blood flow through
the heart, typically as it passes through a heart valve. For example, a
damaged aortic valve might not open wide enough (aortic stenosis) to allow
blood to flow freely through it from the heart into the aorta during
cardiac systole. The turbulent flow across the stenotic valve causes a
buzzing sound, called a murmur, between the "lub" and the
The presence of a heart murmur is occasionally normal
(such as increased flow murmurs during pregnancy), but usually indicates a
Other Heart Sounds
Other heart sounds may be heard, the most common of
which is the "ejection click," associated with mitral valve