THE ANATOMY OF CARDIAC SYSTEM

L1: PERICARDIUM
 Double-walled sac that encloses the heart
 Location: middle mediastinum, post to body of sternum, 2nd to 6th costal cartilage, ant to T5-8 V
 Relation:
- Anterior: separated from ant wall of thorax by lungs & pleura
- Posterior: bronchi, esophagus, descending thoracic aorta
- Lateral: mediastinal surfaces of lungs
 Layers:
- Fibrous pericardium: strong external layer
- Serous pericardium: internal double layer
i. Parietal layer
ii. Visceral layer
 Functions:
- Protects and anchors the heart
- Allows the heart to contract in a frictionless environment
- Prevent overfilling of blood
 Pericardial cavity:
- space between parietal & visceral layer of serous pericardium
- have pericardial fluid that allows the heart to function without friction
 Pericardial sinuses:
- transverse sinus: anteriorly, behind the aorta & pulmonary trunk
- oblique sinus: space behind the left atrium, allows proper filling of the left
atrium
 Arterial supply:
- Fibrous & parietal layer: pericardial branch of internal thoracic artery, musculophrenic artery
- Visceral layer: right & left coronary artery
 Nerve supply:
- Fibrous & parietal layer: phrenic & intercostal nerve ( pain sensitive )
- Visceral layer: sympathetic & parasympathetic NS ( pain insensitive )
 Applied anatomy
- Pericarditis: inflammation of the serous pericardium due to excessive accumulation of
pericardial fluid & causing a pericardium friction rub
- Pericardial effusion: excessive acc of pericardial fluid in the cavity
- Cardiac tamponade: compression of the heart resulting from pericardial effusion & which
can be relieved by pericardiocentesis ( 5th to 6th ICS)

, L3: GROSS ANATOMY OF THE HEART
 Location: middle mediastinum, behind the body of sternum & costal cartilages
 Heart wall:
- Epicardium: visceral layer of serous pericardium
- Myocardium: thick cardiac muscle layer, thicker in ventricles
- Endocardium: endothelial layer
 Relations:
- Anterior: body of sternum, 3rd to 6th cc
- Posterior: T5-8 vertebrae, oesophagus
- Lateral: mediastinal pleura
- Inferior: diaphragm, liver
 Borders:
- Superior: mainly by left atrium
- Right: mainly by right atrium
- Inferior: mainly by right ventricles, from right border to the apex
- Left: mainly by left ventricle
 Apex of the heart: mainly of left ventricle, site for max pulsation, post to 5 th ICS
 Base of the heart: formed mainly by left atrium, related to T6-9
 Surfaces:
- Sternocostal (ant): mainly by RA & RV, mostly covered by lungs
- Diaphragmatic (post): mainly by both ventricles, rests on central tendon of diaphragm
 Grooves:
- Atrioventricular/coronary sulcus: separated atria and ventricles
- Interatrial: separates both atrium
- Interventricular: separates both ventricles
 Crux: meeting point of post IA, post IV, CS
 Chambers:
i. Right atrium
- Receives blood from SVC at the upper end & IVC at lower end
- External feature:
Sulcus terminalis is a groove passing from SVC to IVC, produced by
crista terminalis
Upper part of ST has sinotrial node-pasemaker of heart
- Internal feature:
Smooth posterior part: opening of SVC, IVC, and coronary sinus
Rough anterior part: have many musculi pectinate arising from crista terminalis
Septal wall: presents as a depression (fossa ovalis)
- Auricle: ear-shaped projection, occupied by muscular
reticulum, prevents overdistension of right atrium

ii. Right ventricle