Notesale: Turn your study into money

Document Preview

Extracts from the notes are below, to see the PDF you'll receive please use the links above

---

PERICARDIUM AND HEART
APPLIED ANATOMY

1

The pericardium
• The pericardium comprises fibrous and serous
components
...
It fuses with the roots of the
great vessels above and with the central
tendon of the diaphragm below
...

• Two important sinuses are located between
the parietal and visceral layers
...

• Oblique sinus behind
the left atrium, the
sinus is bounded by the
inferior vena cava and
the pulmonary veins
...
After the
pericardial sac has been opened anteriorly, a
finger can be passed through the transverse
pericardial sinus posterior to the aorta and
pulmonary trunk
...


7

The pericardium
• Cardiac tamponade (heart compression) is due to
critically increased volume of fluid outside the
heart but inside the pericardial cavity; e
...
, due to
stab wounds or from perforation of a weakened
area of the heart muscle after heart attack
(Haemopericardium)
...
This condition is fatal unless
pericardial decompression is effected
immediately
...

• Once the fluid in the cavity exceeds about 250
mL, the diastolic filling is compromised, a
condition known as cardiac tamponade
...

• The patient is placed in a supine position with
the shoulders raised 60° from the horizontal
position
...

With the positions of the cardiac notches of
the lungs and pleura in mind
...
The following structures will be
penetrated by the needle:

11

Pericardiocentesis
• Skin
• Subcutaneous tissue
• Aponeurosis of the
external oblique muscle
of the abdomen
• Anterior lamina of the
aponeurosis of the
internal oblique muscle of
the abdomen
• Rectus abdominis muscle
12

Pericardiocentesis
• Posterior lamina of the
aponeurosis of the
internal oblique and the
transversus abdominis
muscles
...

• Diaphragm
...


13

Pericardiocentesis
• When pericardial
penetration is achieved
there is a sudden “give
...


14

Anatomy of Complications
• The needle is advanced too far and enters the
myocardium of the right ventricle
...

• The needle may enter the pleural cavity,
producing a pneumothorax or a
hydropneumothorax
...

15

Heart surface anatomy
• The outline of the heart can be
represented on the surface by the
irregular quadrangle bounded by
the following four points
• 1
...
5in
(12mm) from the edge of the
sternum;
• 2
...
5in
(12mm) from the sternal edge;
• 3
...
5in
(12mm) from the sternum;
• 4
...
5in
(9cm) from the midline
(corresponding to the apex beat)
...


17

Heart surface anatomy
• The lower border (the
horizontal line joining
points 3 and 4)
corresponds to the right
ventricle and the apical
part of the left ventricle
...

18

19

Auscultation of Heart Valves
• On listening to the heart with a stethoscope,
one can hear two sounds: lu¯b-du˘ p
...

• The second sound (higher-pitched) is
produced by the sharp closure of the aortic
and pulmonary valves
...

• Aortic valve area (A) 2nd
intercostal space
parasternally on right
side
...

• Tricuspid valve area (T) –
lower sternum or just to
right of it
...

• The mitral valve is best
heard over the apex
beat, that is, at the level
of the fifth left
intercostal space, 3
...

(9 cm) from the midline
...

• The aortic valve is best
heard over the medial
end of the second right
intercostal space
...
Later,
fibrous thickening occurs, followed by loss of
flexibility and shrinkage
...


24

Valvular Heart Murmurs
• Apart from the sounds of the valves closing,
lu¯b-du˘ p, the blood passes through the
normal heart silently
...

25

Cardiac Injuries
• Cardiac Contusion
• The heart, although protected by the thoracic
cage, can be squeezed between the sternum
and the vertebral column
...

• The severity of the pain is often unrelated to
the seriousness of the cause
...

27

Referred Pain
• Visceral pain frequently is referred to skin
areas that are innervated by the same
segment of the spinal cord as is the painful
viscus
...

28

Referred Pain
• Another theory is that under normal
conditions the viscus does not give rise to
painful stimuli, whereas the skin area
repeatedly receives noxious stimuli
...

• The right coronary artery primarily supplies
the right atrium, the right ventricle, the sinoatrial (SA) and AV nodes
...

30

• left coronary artery: arises from the
ascending aorta
...

• The left coronary artery supplies most of the
left ventricle, the left atrium, and the
interventricular septum
...

It drains to an opening in the right atrium
...
It is the main tributary of
the coronary sinus
...
It joins the coronary sinus
...

33

The venous drainage of the heart

34

Coronary Artery Disease
• Coronary arteries ; have numerous anastomoses
at the arteriolar level, they are essentially
functional end arteries
...

• Most cases of coronary artery blockage are
caused by an acute thrombosis on top of a
chronic atherosclerotic narrowing of the lumen
...

• (2) Angina pectoris is cardiac pain that occurs on
exertion and is relieved by rest
...


36

• (3) Myocardial infarction occurs when
coronary flow is suddenly reduced or stopped
and the cardiac muscle undergoes necrosis
...
embolos, plug), the region of
myocardium supplied by the occluded vessel
becomes infarcted (rendered virtually
bloodless) and undergoes necrosis
(pathological tissue death)
...

• An area of myocardium that has undergone
necrosis constitutes a myocardial infarct ion (MI)
...

38

Cardiac referred pain
...

• Rupture of the posteromedial papillary muscle is
more common since it is supplied by a single
artery, the right coronary artery
...

41

Coronary Bypass Graft
• A segment of an artery
or vein is connected to
the ascending aorta or
to the proximal part of a
coronary artery and
then to the coronary
artery distal to the
stenosis

42

Coronary Bypass Graft
• The great saphenous vein is commonly harvested
for coronary bypass surgery because it
• (1) has a diameter equal to or greater than that
of
• the coronary arteries,
• (2) can be easily dissected from the lower limb,
• (3) and offers relatively lengthy portions with a
minimum occurrence of valves or branching
...

• In selected patients, surgeons use percutaneous
transluminal coronary angioplasty, in which they
pass a catheter with a small inflatable balloon
attached to its tip into the obstructed coronary
artery
...


45

Foetal Circulation
• Foetal circulation involves three shunts:
– ductus venous,
– ductus arteriosus,
– and foramen ovale

• After birth, a number of changes occur in the
circulatory system because of the cessation of
placental blood flow and start of lung
respiration
...

• Closure of left umbilical vein
forms Ligamentum teres
• Closure of ductus venosus
forms Ligamentum venosum
• Closure of foramen ovale
forms Fossa ovale
• Closure of ductus arteriosus
forms Ligamentum
arteriosum

47

FOETAL CIRCULATION

48

Congenital Anomalies
• Atrial Septal Defects (ASD):
After birth, the foramen
ovale becomes completely
closed as the result of the
fusion of the septum
primum with the septum
secundum
...

49

Atrial Septal Defects (ASD)
• Secundum-type ASDs
are caused by excessive
resorbtion of the SP, or
reduced size of SS or
both
...
This is the most
Clinically significant ASD
...

This results in hypertrophy of the right side of
the heart and underdevelopment of the left
side
...

54

Tetralogy of Fallot
• Most children find that assuming the squatting
position after physical activity relieves their
breathlessness
...

55

Ventricular Septal Defects
• Ventricular septal defects (VSD)are less
frequent than atrial septal defects
...

• Blood under high pressure passes through the
defect from left to right, causing enlargement
of the right ventricle
56

Membranous Ventricular Septal Defect
(VSD)
• This VSD is caused by the
failure of the membranous
IV septum to develop and it
results in left to right
shunting of blood through
the IV foramen
...

57

Coarctation of the Aorta
• Congenital narrowing of
the aorta just proximal,
opposite, or distal to the
site of attachment of the
ligamentum arteriosum
• Clinically, the cardinal sign
of aortic coarctation is
absent or diminished
pulses in the femoral
arteries of both lower
limbs
...

• The dilated intercostal
arteries erode the lower
borders of the ribs,
producing characteristic
notching, which is seen on
radiographic examination
...

• This causes right-to-left shunting of blood with
resultant cyanosis
...

60

Patent ductus arteriosus (PDA)
• Occurs when the ductus arteriosus fails to
close after birth
...

• Prostaglandin E and intrauterine or neonatal
asphyxia sustain patency of the ductus
arteriosus
61

Patent ductus arteriosus
• Prostaglandin inhibitors (e
...
Indomethacin,
acetylcholine, histamine and catecholamines
promote closure of the ductus arteriosus
...

• This movement of
mediastinal structures
must be considered
during physical and
radiological examinations

---