Cardiovascular System Anatomy

Study Notes

The heart is a four-chambered muscular pump located in the middle mediastinum.
It is positioned obliquely, with two-thirds on the left side and one-third on the right.
The average heart size is comparable to a clenched fist.
The average heart weight is 280 grams.
The heart has upper atrial/venous chambers and lower ventricular/arterial chambers.
Atria and ventricles are separated by coronary sulcus externally.

Sternocostal/Anterior Surface: Directed forwards and upwards, formed by the right atrium & auricle, part of the left auricle, anterior surface of the right ventricle (2/3), and anterior surface of the left ventricle (1/3).
Diaphragmatic/Inferior Surface: Flat, facing upwards and backwards, formed by the two ventricles (2/3 left, 1/3 right). Lies over the central tendon of the diaphragm.

Right Border: Formed by the right atrium, rounded and convex. Extends from the superior vena cava (SVC) to the inferior vena cava (IVC).
Inferior Border: Sharp, extends from the IVC to the apex. Contains a notch called the incisura apicis cordis, closer to the apex.
Left Border: Ill-defined, extends from the left auricle to the apex, separating the sternocostal surface from the left surface.

Heart is externally demarcated by grooves.
Atrioventricular Groove: Surrounds the heart, except in front of the pulmonary trunk. Composed of anterior and posterior parts. Contains the right coronary artery, left circumflex branch of the left coronary artery, termination of great cardiac vein, and beginning of coronary sinus.
Posterior Part of atrioventricular groove: Located between the base and diaphragmatic surface, Contains the coronary sinus and anastomosis of the right and left coronary arteries.
Anterior Interventricular Groove: Runs downwards, forwards, and parallel to the left border, meeting the incisura apicis cordis. Indicates the anterior attachment of the interventricular septum, lodges the anterior interventricular artery, and great cardiac vein.
Posterior Interventricular Groove: Runs forwards along the posterior surface, meeting the incisura apicis cordis. Indicates posterior attachment of interventricular septum. Lodges the posterior interventricular branch of the right coronary artery and middle cardiac vein.

Has a muscular extension called the auricle.
Interior of the anterior wall exhibits pectinate muscles.
Has openings for the superior vena cava, inferior vena cava, and coronary sinus.

Has a much thicker wall than the atria.
Muscle projects into the cavity as papillary muscles, ending as chordae tendineae.
Receives deoxygenated blood from the right atrium via the atrioventricular orifice.

Has a muscular extension called the auricle.
Receives oxygenated blood from the lungs via four pulmonary veins.
Pumps blood into the left ventricle through the left atrioventricular or bicuspid/mitral valve.

Forms the apex of the heart.
Its wall is three times thicker than the right ventricle.
Muscle projects into the cavity as papillary muscles.
Receives oxygenated blood from the left atrium via the bicuspid valve and ejects it into the aorta via the semilunar aortic valve.

Supplied by the left and right coronary arteries, which branch from the ascending aorta.
Left Coronary Artery (LCA): Branches to the left anterior descending (LAD) or anterior interventricular artery, the left marginal artery (LMA), and the left circumflex artery (Cx).
Right Coronary Artery (RCA): Branches to the right marginal artery (RMA) and the posterior interventricular artery (Plv).

Collect waste products from the myocardium.
Drain into the coronary sinus.
Major veins include the great cardiac vein, middle cardiac vein, small cardiac vein, and anterior cardiac vein.