Question

Outline arterial blood supply and venous drainage of the heart.

Note: Please type or write answers neatly and legibly.

Thank you for your time.

Answer 1

ARTERIAL SUPPLY OF HEART

The heart is supplied by 2 coronary arteries,arising from ascending aorta.

Both arteries run in the coronary sulcus.

Right coronary and Left coronary artery.

Right Coronary is smaller than left coronary artery.It arises from the anterior aortic sinus.

RIGHT CORONARY ARTERY

BRANCHES

A) Large branches

1. Marginal

2. Posterior inter ventricular

B)Small branches

1.Nodal in 60% cases

2.Right atrial

3. Infundibular

4.Terminal

Area of Distribution

1. Right atrium

2. Ventricles

!)Greater part of the right ventricle ,except the area of adjoining the anterior interventricular groove.

!!)a small part of the left ventricle adjoining the posterior interventricular groove.

3. Posterior interventricular septum

4. Whole of the conducting system of the heart except a part of the left branch of the AV bundle.The SA node is supplied by the left coronary artery in about 40% of cases.

LEFT CORONARY ARTERY

It is larger than right coronary artery.It arises from the left posterior aortic sinus

Branches

A ) Large branches

1. Anterior interventricular

2.Branches of the diaphramatic surface of the left ventricle,including a large diagonal branch.

B ) Small branches

1 .Left atrial

2 .Pulmonary

3 .Terminal

Area of Distribution

1. Left atrium

2 .Ventricles

!) Greater part of the left ventricle,except the area adjoining the posterior interventricular groove

!!) a small part of the right ventricle adjoining the anterior interventricular groove.

3 . Anterior part of the interventricular septum

4 . a part of the left branch of the AV bundle

Cardiac Dominance

10% of cases,right coronary is rather small and not able to give the posterior interventricular branch. In these cases the circumflex artery, the continuation of left coronary artery provides posterior interventricular branch as well as to the AV node.Such cases are left dominant.

Mostly Right coronary gives posterior interventricular artery.These are Right Dominant.

COLLATERAL CIRCULATION

CARDIAC ANASTOMOSIS

The 2 coronary arteries anastomose with each other in myocardium.

Extracardiac Anastomoses

The coronary artery anastomose with the

1. Vasa vasorum of the Aorta
2. Vasa vasorum of the pulm onary arteries
3. The internal thoracic arteries
4. The bronchial arteries
5. The phrenic arteries.

the last 3 anastomoses through the pericardium.These channels may open only in emergencies when the both coronary arteries are obstructed.

VEINS OF THE HEART

These are the great cardiac vein ,the middle cardiac vein,the right marginal vein,the posterior vein of the left ventricle,the oblique vein of the left atrium,the right marginal vein, the anterior cardiac veins, and the venae cordis minimi.

All these veins except the last two drains into the coronary sinus which opens into the right atrium.

The anterior cardiac veins and the venae cordis minimi open directly into the right atrium.

A. Coronary Sinus

It is the largest vein of the heart. situated in the left posterior coronary sulcus.it ends by opening into the posterior wall of the right atrium.It receives the following tributaries

1. The great cardiac vein
2. The middle cardiac vein
3. The small cardiac vein
4. The posterior vein of the left ventricle
5. The oblique vein of the left atrium of Marshall
6. The right marginal vein

B Anterior cardiac veins

It have 3 or 4 small veins, which run parallel to one another on the anterior wall of the right ventricle and usually open directly into the right atrium through its anterior wall

C Venae Cordis Minimi

The venae cordis minimi or Thebesian veins or smallest cardiac veins are numerous small veins present in all 4chambers of the heart which open directly into the cavity. Mose numerous in right side of the heart.