Heart - LO 2
2. Describe the external features of the heart, including which chambers of the heart compose the surfaces and borders.
There are 4 borders of the heart:
Right border: portion of the heart located between the superior and inferior venae cavae
Formed by R. atrium
Left border (obtuse margin): formed predominantly by the L. ventricle with a small contribution from the L. auricle of the L. atrium
Superior (upper) border: formed by the R. and L. atria
This border is important in terms of the close relationship to large vascular structures, such as the ascending aorta, pulmonary trunk, and superior vena cava
Inferior border (acute margin): formed predominantly by the R. ventricle with a contribution from the L. ventricle
There are 6 surfaces or aspects of the heart, including the apex and base:
Sternocostal (anterior) surface: formed predominantly by the R. ventricle with small contributions from the R. atrium & L. ventricle
The coronary & anterior interventricular sulci are visible on this surface
Apex of the heart: formed by the L. ventricle
Often considered as anteriorly facing and directed to the left
Located near the L. midclavicular line, just deep to the L. 5th intercostal space
Right surface: formed by R. atrium
Left surface: formed mainly by the L. border of the heart
Diaphragmatic (inferior) surface: formed mainly by the L. ventricle and portions of the R. ventricle
Very closely associated with the diaphragm
Base of heart (posterior aspect of heart): formed predominantly by the L. atrium with some contribution from the R. atrium
Closely associated with the pulmonary vv. & oblique pericardial sinus
Often considered as posteriorly facing and directed more to the right
There are 3 sulci (grooves) of the external heart that are superficial artifacts of the divisions/walls of the heart:
Coronary (atrioventricular) sulcus: sulcus between the atria and ventricles
Contains the coronary sinus, R. & L. coronary aa., main trunks
Anterior interventricular (IV) sulcus: sulcus between the ventricles; continuous with posterior interventricular sulcus
Located on sternocostal (anterior) surface
Anterior interventricular br. (left anterior descending - LAD) of L. coronary a. & great cardiac v. are located in this sulcus
Posterior interventricular (IV) sulcus: sulcus between the ventricles; continuous with the anterior interventricular sulcus
Located mostly on the diaphragmatic surface
Posterior interventricular br. (posterior descending a.) of R. coronary a. & middle cardiac v. are located in this sulcus
