anatomy 3.2

foramen ovale closes at birth and the remnant of the valve

is the fossa ovalis

the ductus arteriosus becomes the

ligamentum arteriosum in postnatal period

if the cardiac silhouette shouldn't be wider than

50% if so its abnormal

mediastinum

contains all thoracic viscera except lungs

extends from the superior thoracic aperture to the diaphragm

the mediastinum can be artificially divided into superior and inferior parts by

transverse thoracic plane which passes through the sternal angle and the IV disc between T4 and T5

superior mediastinum is located

superior to the transverse thoracic plane

inferior mediastinum is further divided into

anterior

middle

posterior parts

palpating the sternal angle and moving laterally places the finger

on the costal cartilages of rib 2

in a supine patient the following structures relate to the transverse thoracic plane

arch of aorta lies superior

azygos vein drains into the superior vena cava

trachea bifurcates

central tendon of diaphragm lies at level of xiphisternal joint (T9)

when standing the the arch of the aorta is

transected by the transverse thoracic plane

the central tendon may fall to mid level of the xiphisternal joint (between T9-T10

bifurcation of the trachea lies inferior to the plane

contents of mediastinum contents

pericardium

heart and cardiac plexus

phrenic nerves

roots of azygos vein

main bronchi and tracheobronchial lymph nodes

Pericardium is a

sac that surrounds the heart, proximal portion of great vessels and is adherent to the diaphragm

the phrenic nerve and pericardiacphrenic vessels traverse between the

pericardium and pleura

layers of pericardium

fibrous pericardium

parietal layer

visceral layer

fibrous pericardium

outermost layer of the dense connective tissue

parietal layer

of serous pericardium lines the inside of the layer of fibrous pericardium

pericardial cavity

potential space between parietal and visceral layers

contains a thin film of fluid

serous pericardium (mesothelium)

produces a thin film of fluid to facilitate smooth movement of the heart

pericardial effusion

fluid in pericardial cavity due to:

pericarditis exudate

MI/wall rupture, or trauma and lead to blood in the pericardial cavity (hemopericardium)

pericarditis

results in chest pain due to inflammation/infectious diseases affecting the pericardium. it may lead to pericardial effusion

cardiac tamponade

when fluid buildup in the pericardial cavity compresses the heart because the fibrous pericardium does not expand, which impairs venous return and cardiac output

may be lethal if not removed from pericardial cavity by pericardiocentesis

patient with cardiac tamponade will present with

dyspnea, tachycardia and tachypnea

becks triad with cardiac tamponade

low BP, JVD, muffled heart sounds

where do you place the needle for a pericardiocentesis

insert through 5th or 6th ICS near the sternum- possible bc of cardiac notch in the left lung

also could insert in xiphichondral angle- possible risk of injury to the internal thoracic artery or its branches

the main arterial supply to the pericardium is

pericardiacophrenic artery which is a branch of the internal thoracic artery

phrenic nerve carry pain from the

parietal pericardium

pain is referred to C3-C5 dermatomes

the phrenic nerve vs vagus nerve for passing the root of the lung

phrenic passes anterior to the root of the lung

vagus passes posteriorly

the pericardiacophrneic vessels and phrenic nerves lie within or superficial to

the fibrous pericardium

phrenic nerve injury can be a complication of

cardiac surgery or mechanical or ischemic

anterior surface of heart is formed mostly by the

right ventricle and a small part of the right atrium

coronary sulcus separates the

atria from the ventricles

blunt trauma to the anterior chest wall can injure

the right ventricle of the heart

the diaphragmatic surface of the heart is formed mostly by

the left ventricle and a small part of the right ventricle

the base or posterior surface of the heart is formed primarily

by the left atrium and a small part of the right atrium

base of heart in supine vs erect position

S: T5-T8

E: T6-T9

an anterior ulceration of the esophagus can erode into the

left atrium bc it lies directly anterior to the esophagus

truncus arteriosus

ascending aorta, pulmonary trunk

bulbus cordis

smooth outflow tract of ventricles

right- infundibulum, conus arteriosus

left- aortic vestibule

primitive ventricle

Trabeculated part of left and right ventricles

primitive atrium

Trabeculated part of left and right atria

sinus venosus

left horn- coronary sinus, oblique atrial vein

right horn- smooth part of right atrium "sinus venarum"

foramen ovale shunts blood

from right atrium to left atrium prior to birth

after birth higher pressure in left atrium pushes

septum primum to the right thereby closing foramen ovale resulting in fossa ovalis

incomplete closure of foramen ovale is considered an

atrial septal defect (ASD)

large ASDs cause a left to right shunt of blood which causes dilation of right atrium and ventricle due to abnormally high pressures

ventricular septal defects (VSD) occur more frequently in

membranous part of the septum

severe defects can lead to pulmonary hypertension and cardiac failure

membranous septum forms from

the right and left bulbar ridges and endocardial cushions

the muscular septum grows up from the

apex to fuse with the membranous portion

VSD is the most common cardiac malformation and is most often the

membranous part

during development the neural crest cells migrate

toward the heart via the aortic arches to form the bulbar and truncal ridges

the posterior wall of the right atrium is

smooth derived from sinus venosus

the rough muscular of right atrium has

pectinate muscle in the anterior region and in the auricle (primitive atrium)

the crista terminalis is

a ridge that separates the smooth from the rough walls of the atrium. externally there is a corresponding groove called the sulcus terminalis

the fossa ovalis is a

remnant of foramen ovale seen in the right atrium

in the right atrium the openings for

coronary sinus, superior and inferior vena cave are visible

what valve does the right ventricle have

tricuspid (atrioventricular)

the right ventricle also has

3 papillary msucles (anterior, posterior and septal) and chordae tendineae

trabeculae carneae is seen in

right ventricle

septomarginal trabecula (moderator band)

in right ventricle and carries part of the right branch of AV bundle

conus arteriosus (infundibulum)

smooth outflow tract to pulmonary in right ventricle

interventricular septum in right atrium has a

small membranous part and larger muscular part

ventricular septal defects

occur more commonly in the membranous part

inside wall of left atrium is

essentially smooth except for pectinate muscle

the left ventricle has what kind of valve

bicuspid (mitral)

how many papillary muscles in left ventricle

2 (anterior and posterior) that are larger than the right ventricle

in left ventricle the chordae tendineae and trabeculae carneae are

finer and more numerous than in right ventricle

ventricular wall is 2-3 times as thick as the

right ventricle and muscular septum bulges into right ventricle

aortic vestibule in left ventricle is

smooth walled non muscular outflow tract to aorta

both the aortic and pulmonary valves are

tricuspid semilunar valves

openings for the coronary arteries are behind the

right and left semilunar cusps within the aortic sinuses (sinuses of valsalva)

auscultation of aortic valve

2nd ICS right sternal border

auscultation of pulomonic valve

2nd ICS left sternal border

auscultation of tricuspid valve

5th ICS left ventricular border

auscultation of mitral valve

5th ICS midclavicular line

S1

closing of AV valves

S2

closing of semilunar valves

valvular heart disease can result in

stenosis or insufficiency

in mitral valve prolapse

the leaflets are enlarged or floppy and blood regurgitates into the left atrium during systole causing a murmur

the fibrous skeleton

separates the musculature of the atria from the ventricles and provides attachment for the valves of the heart

valves are attached to the

4 fibrous rings, annuli fibrosi, of which are fused to one another

cardiac muscle fibers attach to the

fibrous skeleton of the heart

coronary arteries

first branches of the aorta and supply the myocardium and epicardium

the endocardium receives oxygen and nutrients via diffusion

coronary arteries arise form the aorta in the

right and left aortic sinuses (sinuses of valsalva)

the right coronary artery is located

in the atrioventricular groove (coronary sulcus)

left coronary artery is

short. it divides into the circumflex and anterior interventricular branches

look at slide 61 heart and middle mediastinum

the right coronary artery supplies the

right atrium, SA and AV nodes and posterior part of interventricular septum

the left coronary artery supplies most of the

left atrium and ventricles, IVS and AV bundles (may supply AV node but less often

when the posterior interventricular artery arises from the RCA it is considered a

right dominant coronary circulation (most common)

when the LCA gives rise to the posterior ventricular it is considered

left dominant circulation

Co-dominance can exist between

RCA and LCA both contribute to the posterior interventricular region

the coronary arteries are the first branches of

the aorta

they supply the myocardium and epicardium

the RCA gives rise to what branches

SA nodal

right marginal

AV nodal

posterior interventricular (most often right dominance)

the LCA divides into

circumflex

anterior interventricular (aka LAD)

anterior interventricular (LAD) from LCA supplies

the anterior 2/3 of septum

posterior interventricular of RCA supplies the

posterior 1/3 of septum

anteroseptal myocardial infarctions are commonly caused

by rupture of an unstable atherosclerotic plaque in the left descending artery

what arteries can be used for bypass

great saphenous vein or the internal thoracic artery

the great and small cardiac veins drain the

sternocostal surface along the anterior cardiac veins

the coronary sinus (derived from left horn of sinus venosus) receives the

posterior interventricular/middle cardiac vein on the diaphragmatic surface of the heart

it also receives the small cardiac and posterior ventricular veins

both sympathetic and parasympathetic nerves contribute to

cardiac plexus located on the anterior surface of the trachea at the bifurcation (deep) and on the anterior surface of the aortic arch