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					   Chapter V Thorax

D. Heart and blood vessels

          Heart

              by Dr. Zhuo-ren Lu
                 I. Inspection

    l Observe protrusion of precordium and
    apical impulses with tangential lighting.
    Check other pulsation in the anterior chest.
   l The normal impulse is located generally
    in the fifth intercostal space, 0.51cm
    within the midclavicular line.
 l An abnormal position of impulse generally indicates
 cardiac enlargement, but the causes of cardiac
 displacement such as scoliosis, funnel sternum, pleural
 effusion and pulmonary fibrosis, a big mass in
 abdominal cavity should be eliminated.
 l Left ventricular hypertrophy results in downward
 (6th space) and outward displacement of the apex beat.
 Right ventricular hypertrophy causes strong pulsation
 under the xiphoid or/and a change of apex beat in
 position towards left (5th space).
l A feeble diffuse impulse ( more than 22.5cm in
 diameter) may suggest dilation. If the thrust is forcible,
 hypertrophy is suggested.
                  II. Palpation
1. The hand should then be placed on the all areas of
  the precordium in order to detect any abnormal
  pulsation, vibrations or thrill, and pericardium
  friction rub.
2. The pulsation of the abdominal aorta may often
  be felt in the epigastric area. Also, the impulse
  from right ventricle can be felt by the fingertips
  placed under the xiphoid process while inspiration.
3. Thrill
A thrill is a palpable murmur from the heart or
great vessels. The main reason is the obstruction to
blood flow through a narrowed valve or the certain
abnormal congenital defects. Thrills may be
systolic, diastolic or may occur continuous in time.
l In aortic stenosis and aneurysm of the great
vessels at the root of the neck, a powerful systolic
thrill may be palpable over the 2nd interspace,
usually spreading upwards to the neck.
l To the left of the sternum in the 2nd interspace,
pulmonary stenosis gives rise to a similar systolic
thrill.
l      In the left 3rd or 4th parasternal area,
systolic thrills are due to congenital lesions of
the interventricular septum of heart.
l Diastolic thrills at the apex are usually due to
mitral stenosis.
l The combination of a systolic and diastolic
thrill occurs over the base of the heart in
patients with patent ductus arteriosus.
l Timing a thril is best accomplished by either
the apex beat or the carotid artery palpation,
both of which correspond to ventricular systole.
4. Pericardial friction rub
Pericardial friction rub is caused by a fibrinous
pericarditis.
l It is present during both phases of the cardiac
cycle. In the presence of pericardial effusion the
rub will disappear because of the separation of
the visceral and parietal layers by the fluid.
lOften rubs are more readily palpated with
sitting erect and leaning forward.
l They are best palpated in the left 3rd and 4th
intercostal spaces at the sternal border.
              III. Percussion
l Percussion of cardiac dullness border starts to
the left on the chest, from 23cm apart from the
apical impulse towards cardiac dullness (relative
cardiac dullness). Percussion is performed from
left towards cardiac dullness in the 4th, 3rd and
2nd intercostal spaces. Next, to the right of the
chest, percussion is done in the midclavicular line
down to a dull point (the upper margin of liver).
Then, percuss from right towards cardiac dullness
in the 4th (above the liver dullness), 3rd, and 2nd
intercostal spaces.
 l Measure the vertical distances from each point of
 cardiac dullness to the mid-sternal line with a stiff
 ruler.
 l When the left border of cardiac dullness falls
 outside the midclavicular line, it usually indicates
 that the left ventricle is enlarged.
 l If the left border of cardiac dullness goes out of
 left midclavicular line (the left cardiac border
 towards left in the 5th intercostal space), it suggests
 that the right ventricle enlarged.
l The cardiac dullness enlarged towards two sides:
 (1)both left and right ventricles enlarged, (2) a large
 volume of fluid in the cavity of pericardium. In this
 case, the cardiac borders will be changed following
 the change of the patient's position.

				
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