The Heart Is A Hollow, Muscular Organ Of The Middle Mediastinum Orientated Obliquely
961 WordsAug 1, 20154 Pages
The heart is a hollow, muscular organ of the middle mediastinum orientated obliquely in the chest, divided into four chambers by an atrioventricular constriction and the inter-ventricular septum. Surface grooves indicate these divisions: the atria are separated from the ventricles by the coronary sulcus (the atrioventricular groove) with a hiatus anteriorly at the root of the pulmonary artery (PA). The atria are separated posteriorly by the inter-atrial groove though this is scarcely marked, and anteriorly this is hidden by the pulmonary artery and aorta. The ventricles are separated posteriorly by the posterior longitudinal sulcus on the diaphragmatic surface and anteriorly by the anterior longitudinal sulcus on the sternocostal surface, extending from the base of the heart to a notch, the incisura apices cordis on the acute margin of the heart just to the right of the apex .
Internally, the right ventricle is delimited by the tricuspid valve annulus and the pulmonary valve and is anatomically divided into three components : the inlet (tricuspid valve, chordae tendinae, papillary muscles), the trabeculated myocardium of the apex and the outlet region (infundibulum). These regions are anatomically divided into anterior, lateral and inferior walls with basal, mid and apical sub-regions for each . The internal surface of the RV has three prominent muscular bands: the parietal, septomarginal and moderator bands. The parietal band, or conal septum, which runs on to