By
Prof.
Saeed Abuel Makarem
Pericardium• A fibro-serous sac• Surrounds the heart &
proximal part of its great vessels (Aorta, Pulmonary artery, SVC, IVC, & 4 pulmonary veins)
• Formed of:• Outer fibrous layer• Inner serous sac• Serous sac has 2 layers:• Parietal & Visceral
(epicardium)
Fibrous Pericardium• Conical or flask shape• Apex: directed upwards fused
with adventitia of 3 big vessels• Base: rests on diaphragm• Fuses with central tendon of
diaphragm.• Posteriorly: Separated by post.
Mediasinum from middle four thoracic vertebrae (5 to 8)
• Anteriorly: body of sternum, costal cartilages from 2 to 6, ant. Border of lung & pleura, remains of thymus gland & two Sterno-pericardial ligaments
• Extends from 2nd to 6th rib
Located in the middle mediastinumposterior to the body of sternum and 2nd-6th costal
cartilagesAnterior to T5-T8 vertebrae
1-1.5 cm to the right of the sternum
5-7.5 cm to the left of median plane at the level of 5th intercostal space
Function of serous pericardium:• 1- Lubrication to prevent friction• 2- Prevent adhesion of the heart to its surrounding
Function of fibrous pericardium1 -Maintain the central position of the
heart2-Keeps large vessels open
3-Helps venous return4-Acts as a wall for the serous
pericardium.5 -Prevents over loading &
overdistention of the heart
Serous pericardiumSerous sac that has been invaginated by developing heart in the fetal lifeVisceral layer: Epicardium.
Parietal layer: Lines the fibrous pericardiumPericardial cavity: potential space.
Sinuses of pericardium• 2 sinuses in the serous
pericardium are formed during development of the heart (Transverse & Oblique)
• Transverse sinus• A recess behind pulmonary
trunk & ascending aorta• Boundaries:• Ant: Pulmonary trunk &
ascending aorta.• Post: SVC &Upper part of
the 2 atria • Above: Rt. Pulmonary artery• Below: the 2 atria mainly Lt.
• Oblique sinus• It separates the base of heart
(left atrium) from posterior mediastinum (descending aorta & esophagus)
• Boundaries:• Ant: back of Lt. atrium• Post: fibrous pericardium &
posterior mediastinum (esophagus & descending aorta )
• Left: 2 Left pulmonary veins• Right: 2 right pulmonary veins &
IVC
Blood SupplyArterial Supply:
Mainly supplied by pericardiophrenic and musculophrenic arteries, branches of internal thoracicAlso supplied by pericardial branches of bronchial, esophageal and superior phrenic arteriesVisceral layer of the serous pericardium (epicardium) supplied by the branches of the coronary arteriesVenous drainage: Veins are tributaries of azygos
system. Pericardiophrenic veins also drain into the internal thoracic vein
Nerve Supply
The fibrous pericardium and the parietal layer of the serous pericardium are
supplied by the phrenic nerves .
The visceral layer of the serous pericardium is innervated by (autonomic fibers) branches of the sympathetic trunks and the vagus nerves
Heart• Muscular pump that keeps
circulation going on.• It is the size of hand’s fist of
the same person• 2/3 of its breadth lies to left of
median plane and 1/3 right to median plane
• It is conical in shape having an apex, base,
• Sterno-costal, diaphragmatic, surfaces
• and right, and left borders.
External Features: Surfaces
The heart has:
Sternocostal (Anterior) surface
Diaphragmatic (Inferior) surface
Base (Posterior surface)
Apex
Apex
• Directed downwards, forwards & to left
• Lies in LT. 5th Intercostal space 3 & ½ inches ( 9 cm) from median plane.
• Formed only by LT. ventricle.
• Pericardium & diaphragm separate the apex from fundus of stomach
Base• Directed backwards and
slightly to right.• Formed by 2 atria mainly
the left atrium.• Separated from post
Mediastinum by oblique sinus of pericardium
• Lies opposite middle 4 thoracic vertebrae (5 to 8)
• Bounded inferiorly by coronary groove that lodge the coronary sinus.
Sternocostal surface
*Sterno-costal surface• Lies behind body of sternum &
3rd to 6th costal cartilages.• Divided by coronary groove into:• Atrial part: Rt. Atrium• Ventricular part: the two
ventricles, mainly Rt.• Borders:• Upper: Straight, formed by the 2
atria but concealed by the ascending aorta & pulmonary trunk.
• Lower: Concave formed by Rt. Ventricle & small apical part of Lt ventricle
• Rt.: Convex formed by Rt. Atrium• Lt.: Convex ,formed by Lt. auricle
and Lt. ventricle.
Diaphragmatic surface
• Left 2/3 of this surface are formed by Lt ventricle
• Rt. 1/3 is formed by Rt. Ventricle
• The 2 ventricles are separated by post. Interventricular groove.
The groove lodges the post. Interventricular artery & middle cardiac vein
Surface anatomy of Heart• Point 1: Lower border of 2nd Lt
costal cartilage one & half inches from the median plane.
• Point 2: Upper border of Rt. 3rd costal cartilage one inch from median plane.
• Point 3: Upper border of Rt. 6th costal cartilage one inch from its junction with the sternum.
• Point 4: Apex Lt. 5th Intercostal space 3 ½ inches from median plane.
Surface anatomy of the valves
Pulmonary: Left 3rd sternocostal junctionAortic: Left 3rd Intercostal space just left to sternumMitral: Left 4th sternocostal junctionTricuspid: 4th Intercostal space near the middle line.
Auscultation of the cardiac valves
Surface anatomy
A
Arterial SupplyIt is supplied by right & left coronary arteries
Coronary arteries arise from the ascending aorta immediately above the aortic valves
Coronary arteries and their branches are distributed over the surface of the heart lying within the subepicardial connective
tissue
Right Coronary ArteryArises from anterior sinus of ascending aortaRuns between the pulmonary
trunk and right auricle
Runs in the atrioventricular grooveAt the inferior border of the heart it turns posteriorly in the atrioventricular grooveAnastomosis with a branch from the left coronary artery in the posterior interventricular groove
Right Coronary Artery: Branches1-Right conus artery
2-Anterior ventricular branches: 2-3 in number ,
3-Marginal branch4-Posterior ventricular
branches, which gives a branch to atrioventricular node
6-Posterior interventricular artery
7-Atrial branches, & artery of the sinuatrial node which also supplies atria
Left Coronary ArteryLarger than the rightSupplies major part of the heartArises from the left posterior aortic sinusRuns between the pulmonary trunk and left auricleRuns in the atrioventricular groove
Divides into anterior interventricular & circumflex branches
Left Coronary Artery: BranchesAnterior interventricular artery, which gives a small conus artery
Circumflex artery, gives:
Left marginal
Anterior ventricular
Posterior ventricularAtrial branches
Coronary Artery Anastomoses
Although anastomosis do exist between the terminal branches of the right and
left coronary arteries ,
But these are not large enough to compensate for any sudden blockage of a large branch.
A sudden blockage of the larger branches results in myocardial infarction .
Venous Drainage of the HeartMost of the blood drains into the right atrium through the coronary sinus.Coronary sinus:
Lies in the posterior part of the atrioventricularIt is the continuation of the great cardiac veinOpens into the right atrium to the left of the inferior vena cavaTributaries: small and middle cardiac veins, posterior vein of the left ventricle, oblique vein of the left atrium
Anterior cardiac veins drain directly into the right atriumVena cordis minimi open directly into heart chambers
anterior