Anatomy of heart

HUMAN HEART

• The human heart is an organ that pumps blood throughout the body via the circulatory system, supplying oxygen and nutrients to the tissues and removing carbon dioxide and other wastes.

• The human heart is situated in the middle mediastinum, at the level of thoracic vertebrae T5-T8.
• The base of the heart is located along the body’s midline with the apex pointing toward the left side.
• Base (posterior surface) of the heart is formed mainly by Left atrium & small part by right atrium.
• Because the heart points to the left, about 2/3 of the heart’s mass is found on the left side of the body and the other 1/3 is on the right.

Weighs: 

• in men– between about 10 to 12 ounces (280 to 340 grams)
• in women– 8 to 10 ounces (230 to 280 grams)

• The human heart has four chambers: two upper chambers (the atria) and two lower ones (the ventricles).
• The heart’s outer wall consists of three layers. 

1. The outermost wall layer, or epicardium, is the inner wall of the pericardium.  
2. The middle layer, or myocardium, contains the muscle that contracts. 
3. The inner layer, or endocardium, is the lining that contacts the blood.

• The tricuspid valve and the mitral valve make up the atrioventricular (AV) valves, which connect the atria and the ventricles. 
• The pulmonary semi-lunar valve separates the right ventricle from the pulmonary artery, and the aortic valve separates the left ventricle from the aorta.
• The heartstrings, or chordae tendinae, anchor the valves to heart muscles.
• Right side of mediastinal shadow is formed by SVC/ Right brachiocephalic vessels,IVC and Right atriumRight atrium,Superior vena cava,Inferior vena cava are seen on the right side of the cardiac silhouette in chest X-ray.Normal Axis of the heart is best described as being between – 30 to +90.  

BORDERS & SURFACES OF HEART

  GROOVES (Sulci) OF HEART

  A. ATRIOVENTRICULAR GROOVE:

• Atria are separated by ventricles by atrioventricular Sulcus (atrioventricular groove, also called coronary sulcus).
• It is divided into anterior & posterior parts. 
• The right half of anterior part is large & lodges right coronary artery.
• Left half of anterior part is small & lodges circumflex branch of left coronary artery.
• Posterior part of coronary sulcus contains coronary sinus & great cardiac vein. 

B. INTERVENTRICULAR GROOVES

• Right & left ventricles are separated by interventricular grooves.
• Anterior interventricular groove is nearer to left margin of heart & contains anterior interventricular artery (also called left anterior descending artery) & great cardiac vein.
• Posterior interventricular groove is situated on diaphragmatic (inferior) surface.
• It contains posterior interventricular artery (continuation of RCA) & middle cardiac vein