Description: Hollow, muscular, somewhat conical, central pumping organ
Muscular walls: Formed by cardiac muscle
Function: Pumps blood throughout the body
Anatomical Points
Apex: Directed downwards, forwards, and to the left
Base: Directed upwards, backwards, and to the right
Surfaces: Three surfaces - Sternocostal, diaphragmatic, and left surface
Borders: Three borders - Right, inferior, and left
Dimensions
Apex to base: 12 cm
Anteroposterior diameter: 6 cm
Greatest transverse diameter: 8-9 cm (should be less than 50% of the thorax diameter)
Presenting Parts
Apex: Formed by the left ventricle
Base: Formed by atria (2/3 by the left atrium, 1/3 by the right atrium)
Three Surfaces:
Sternocostal surface
Diaphragmatic surface
Left surface
Three Borders:
Right border: Superior and inferior vena cava
Inferior border: Along the diaphragmatic surface
Left border: Mainly the left ventricle
Grooves and Sulci
Atrial and Ventricular separation: By inter-atrial septum and atrioventricular groove
Anterior Interventricular Groove: Contains anterior interventricular branch of the left coronary artery and great cardiac vein
Posterior Interventricular Groove: Contains posterior interventricular branch of the right coronary artery and middle cardiac vein
Coronary Sulcus: Encircles the heart, it is a transverse groove on surface the of the heart that separates the atria from the ventricle it is present between right ventricle and atrium of heart it supplies the cardiac muscles of both the chambers of the heart contains the trunks of the coronary arteries
Coronary Arteries
Right Coronary Artery: Arises from the anterior aortic sinus
Left Coronary Artery: Arises from the left posterior aortic sinus
Functional End Arteries: Coronary arteries are functional end arteries
Crux of the Heart
Definition: Meeting point of the inter-atrial groove, posterior interventricular groove, and the posterior part of the atrioventricular groove
Internal Anatomy
Chambers: Right atrium, right ventricle, left atrium, left ventricle
Right Atrium: Receives deoxygenated blood from the superior and inferior vena cava
Smooth part: Sinus venarum
Rough part: Contains pectinate muscles
Structures: Crista terminalis, fossa ovalis
Right Ventricle: Contains trabeculae carneae, papillary muscles, and chordae tendineae
Valves: Tricuspid valve (anterior, posterior, and septal cusps)
Left Atrium: Receives oxygenated blood from pulmonary veins
Structures: Left auricle
Left Ventricle: Contains trabeculae carneae, papillary muscles, and chordae tendineae
Valves: Mitral valve (anterior and posterior cusps)
Circulation
Pulmonary Circulation: Right atrium → right ventricle → pulmonary trunk → lungs (oxygenation) → left atrium
Systemic Circulation: Left atrium → left ventricle → aorta → body
Portal Circulation: Not discussed in detail
Layers of the Heart
Epicardium: Formed by the serous pericardium (visceral layer)
Myocardium: Thickest layer, composed of cardiac muscle
Features: Short, cylindrical, branching fibers with intercalated discs