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Blood Supply Of Heart|Thorax|Anatomy

 Blood Supply Of Heart

The heart is supplied by two coronary arteries, right and left, which arise from the ascending aorta.

RIGHT CORONARY ARTERY

It is smaller than the left coronary artery. It arises from the anterior aortic sinus of ascending aorta and descends in the right anterior part of the coronary sulcus up to the junction of right and inferior margins of the heart. 

Here, it gives a marginal branch to the lower margin of the sternocostal surface. Then it curves around the lower margin of the heart to reach the diaphragmatic surface where it continues in the right posterior part of the coronary sulcus. 

After crossing the crux of the heart, it terminates by anastomosing with the circumflex branch of the left coronary artery.

BRANCHES

These are:

• Larger branches

~Marginal artery

~ Posterior interventricular artery

• Smaller branches

   ~SA nodal artery in 60% cases

    ~Right conus artery

    ~Unnamed branches to the right atrium and left ventricle




LEFT CORONARY ARTERY

It is larger than the right coronary artery. It arises from the left posterior aortic sinus. It passes to the left between the pulmonary trunk and left auricle. 

Here, it gives the anterior interventricular artery, and then, it curves around the left border of the heart to continue as the circumflex artery in the left posterior coronary sulcus. 

Near the posterior interventricular sulcus, it terminates by anastomosing with the right coronary artery.

BRANCHES

These are:

• Larger branches

~Anterior interventricular/left anterior descending artery (LAD)

~Diagonal artery

~Circumflex artery

• Smaller branches

~Left conus artery

~Unnamed branches to the left atrium and left ventricle

APPLIED ANATOMY

Angina pectoris

• It is pain (moderately severe) felt in the left precordium, which often radiates to the left shoulder, medial side of left arm and forearm. 

• It usually occurs on exertion which remains for about 20 min and relieved on taking rest. 

• The angina pectoris occurs due to narrowing of coronary arteries, leading to ischemia of cardiac muscle.

Myocardial infarction (MI)

A sudden blockage of one of the major branches of coronary arteries leads to myocardial ischemia and myocardial necrosis. It often leads to death. Clinically, it presents as:

• Sinking pain in the chest for more than 30 min

• Nausea, vomiting, sweating, shortness of breath, and tachycardia

• Pain radiates to the left shoulder, left side of arm, and forearm.

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