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

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