Anatomy of the Heart, Pericardium, and Great Vessels Flashcards

Flashcards covering pericardium anatomy, SVC and brachiocephalic veins, arterial blood supply, internal chamber structures, external surface boundaries, and valve auscultation points.

What is the definition of the pericardium?

A conical fibroserous sac surrounding the heart and the roots of its great vessels.

What is the location and site of the pericardium in the thorax?

It is located in the middle mediastinum, extending from the sternal angle above to the diaphragm below, and anteriorly from the 2nd to 6th costal cartilages.

What are the four primary functions of the fibrous pericardium?

It protects the heart, maintains its position, prevents over distension, and keeps the mouths of large vessels open.

What is the nerve supply of the fibrous pericardium and parietal serous pericardium?

Phrenic nerves, which are sensitive to pain.

What is the nerve supply of the visceral serous pericardium?

Autonomic fibers as the heart, which are insensitive to pain but sensitive to ischemia.

Where is the needle inserted during pericardiocentesis to avoid injury to the pleura or internal thoracic vessels?

In the 5th or 6th intercostal spaces and Left costoxiphoid angle very close to the sternum.

What are the boundaries of the transverse pericardial sinus?

In front: Ascending aorta and pulmonary trunk; Above & behind: Right pulmonary artery; Below & behind: S.V.C. and 2 atria (mainly Left).

What are the functions of the transverse pericardial sinus?

It acts as a dead space for dilatation of great vessels during exercise and assists in the fixation of the heart during cardiac surgery.

What are the boundaries of the oblique pericardial sinus?

In front: Back of Left atrium; Behind: Fibrous pericardium separating it from descending aorta and esophagus; On Right side: S.V.C., 2 Right pulmonary veins, and I.V.C.; On Left side: 2 Left pulmonary veins; Below: Open in pericardial cavity.

Where do the two brachiocephalic veins unite to form the Superior Vena Cava (SVC)?

Behind the lower border of the 1st right costal cartilage, close to the sternum.

What are the tributaries of the left brachiocephalic vein?

Vertebral vein, First intercostal vein (sometimes), Inferior thyroid vein, Internal thoracic vein, and Left superior intercostal vein.

What is the length and mediastinal placement of the Superior Vena Cava (SVC)?

Length is about 2 inches ($5\,cm$). Its upper 1/2 lies in the superior mediastinum while its lower 1/2 lies in the middle mediastinum inside the fibrous pericardium.

At what level does the azygos vein enter the SVC?

At the level of the 2nd right costal cartilage, just before the SVC pierces the pericardium.

What structures lie posterior to the Superior Vena Cava?

Right principal bronchus, right pulmonary artery, and right vagus on the right side of the trachea.

Where do the Right and Left Coronary Arteries originate?

They arise from the ascending aorta immediately above the aortic valve: Right Coronary Artery from the anterior aortic sinus, and Left Coronary Artery from the left posterior aortic sinus.

In what percentage of individuals does the S.A. Nodal artery originate from the Right Coronary Artery?

$65\%$ of people.

What areas are supplied by the Left Anterior Descending (LAD) artery?

It gives off the left conus artery, supplies both ventricles, and supplies the anterior 2/3 of the interventricular septum.

What defines Right dominance, Left dominance, and Codominance in coronary circulation?

Right dominant ($67\%$): posterior interventricular artery is a branch of RCA; Left dominant ($15\%$): posterior interventricular artery is a branch of circumflex artery; Codominance ($18\%$): branches of both RCA and LCA reach the crux and give branches in the posterior interventricular groove.

What is the length of the coronary sinus and where does it open?

It is a short venous channel ($3\,cm$) running from left to right in the posterior part of the coronary groove, opening into the right atrium just to the left of the IVC.

What are the tributaries of the coronary sinus?

Great cardiac vein, Middle cardiac vein, Small cardiac veins, Posterior vein of left ventricle, and Oblique vein of left atrium.

What structure separates the atrium proper from the sinus venarum in the interior of the right atrium?

Crista terminalis, a muscular vertical ridge extending between the S.V.C. and I.V.C. openings.

What openings are received by the sinus venarum of the right atrium?

Openings of S.V.C., I.V.C., coronary sinus, anterior cardiac veins, and venae cordis minimi.

What is the wall thickness of the right atrium compared to the right ventricle?

Right atrium wall is $3\,mm$ thick; Right ventricle wall is $9\,mm$ thick.

What are the attachments and function of the Septomarginal Trabecula (Moderator Band)?

It is a muscular band extending from the interventricular septum to the base of the anterior papillary muscle. Its functions are to prevent overdistension of the right ventricle and allow rapid transmission of electric impulses.

Where is the apex of the heart located and what chamber forms it?

It is formed by the left ventricle and lies in the left 5th intercostal space of the Left midclavicular line, 3 1/2 inches ($9\,cm$) from the median plane.

What structural proportions form the sternocostal surface of the heart?

It is formed 2/3 by the right ventricle and 1/3 by the left ventricle.

What structural proportions form the diaphragmatic surface of the heart?

It is formed 2/3 by the left ventricle and 1/3 by the right ventricle.

What are the surface anatomical positions of the four cardiac valves?

Pulmonary valve: Behind Left 3rd sternocostal junction; Aortic valve: Opposite Left 3rd intercostal space, behind sternum Left margin; Mitral valve: Opposite Left 4th sternocostal junction, behind Left 1/2 sternum body; Tricuspid valve: Opposite 4th intercostal space, behind sternum center.

What are the exact auscultatory areas for listening to each heart valve?

Pulmonary valve: Left 2nd intercostal space (left parasternal); Aortic valve: Right 2nd intercostal space (right parasternal); Mitral valve: Heart apex; Tricuspid valve: Xiphisternal junction.