Mediastinum Flashcards

Front 1

mediastinum

Back 1

occupied by the mass of tissue between the two pulmonary cavities, center of thoracic cavity, contains heart

Front 2

superior mediastinum

Back 2

extends from superior thoracic aperture to the horizontal plane (transverse thoracic plane) that includes the angle of Louis and the 4th ICS, contains trachea and superior parts of the great vessels

Front 3

inferior mediastinum

Back 3

extends from the horizontal plane that includes the angle of Louis and the 4th ICS inferiorly to the diaphragm, further divided into the anterior, middle, and posterior parts

Front 4

middle mediastinum

Back 4

contains the heart and the great vessels

Front 5

posterior mediastinum

Back 5

contain parts (e.g. esophagus) that pass through multiple layers of the mediastinum

Front 6

pericardium

Back 6

fibroserous membrane that covers the heart and the beginning of its great vessels, composed of 2 layers, fibrous pericardium and serous pericardium

Front 7

fibrous pericardium

Back 7

tough, external layer of the pericardium, continuous with the central tendon of the diaphragm and the tunica adventitia of the great vessels, attached anteriorly to the sternum by the sternopericardial ligaments, controls filling/expansion of heart, intimate with the parietal serous pericardium

Front 8

parietal layer of serous pericardium

Back 8

lines internal surface of the fibrous pericardium, glistening serous membrane, reflected on the heart at the great vessels as the visceral layer of serous pericardium

Front 9

visceral layer of serous pericardium

Back 9

covers the heart intimately, epicardium

Front 10

pericardial cavity

Back 10

potential space between opposing layers of the parietal and visceral layers of serous pericardium, normally contains a thin film of fluid that enables the heart to move and beat in a frictionless environment

Front 11

transverse pericardial sinus

Back 11

lies between the great vessels (aorta/pulmonary trunk and SVC/IVC/veins), posterior to aorta and anterior to the SVC, superior to the atria

Front 12

oblique pericardial sinus

Back 12

lies between the IVC and pulmonary veins, created from pericardial reflection around veins, posterior to the base of the heart (L. atrium), can be entered inferiorly, elevates heart on the posterior side

Front 13

pericardiacophrenic artery

Back 13

branch of the internal thoracic artery, often accompanies the phrenic nerve to the diaphragm, arterial supply of the pericardium

Front 14

musculophrenic artery

Back 14

terminal branch of the internal thoracic artery

Front 15

bronchial, esophageal, and superior phrenic arteries

Back 15

branches of the thoracic aorta

Front 16

coronary arteries

Back 16

first branches of the aorta, innervate the visceral layer of serous pericardium

Front 17

venous drainage of pericardium

Back 17

pericardiacophrenic veins (tributaries of the brachiocephalic veins) and variable tributaries of the azygos venous system

Front 18

nerve supply of the pericardium

Back 18

-phrenic nerve-(C3-C5), primary source of sensory fibers, pain sensations conveyed by these nerves are commonly referred to the C3-C5 dermatomes, somatic

-vagus nerve-unknown function

-sympathetic trunk-vasomotor

Front 19

heart

Back 19

a double, self-adjusting, suction and pressure pump, work in unison to propel blood to all parts of the body

Front 20

right heart

Back 20

receives poorly oxygenated blood from the SVC and IVC and pumps it through the pulmonary trunk to the lungs for oxygenation

Front 21

left heart

Back 21

receives well-oxygenated blood from the lungs through the pulmonary veins and pumps it into the aorta for distribution to the body

Front 22

atria

Back 22

left and right, receiving chambers that pump blood into the ventricles

Front 23

atrioventricular pumps

Back 23

two, left and right, pumping action, constitute the cardiac cycle

Front 24

diastole

Back 24

begin cardiac cycle, period of ventricular filling and elongation

Front 25

systole

Back 25

end cardiac cycle, period of ventricular shortening and emptying

Front 26

lub sound

Back 26

occurs as the blood is transferred (sucked) from the atria into the ventricles, sound of the pulmonary and aortic valves closing

Front 27

dub sound

Back 27

occurs as the ventricles expel blood from the heart, sounds made by the snapping shut of the valves

Front 28

endocardium

Back 28

thin internal layer, lining membrane of the heart that also covers its valves

Front 29

myocardium

Back 29

thick, helical middle layer composed of cardiac muscle, esp. thick in ventricle

Front 30

epicardium

Back 30

thin external layer (visceral serous pericardium)

Front 31

fibrous skeleton of the heart

Back 31

anchor heart muscle fibers, network of dense collagen forming four fibrous rings, a R. and L. fibrous trigone, and the membranous parts of the interatrial and interventricular septa, has four functions
1. keeps the orifices of the AV and semilunar valves patent
2. provides attachments for the leaflets and cusps of the valves
3. attachment for myocardium, which forms a ventricular myocardial band
4. forms an electrical insulator, separates impulses of the atria and ventricle (so they contract independently

Front 32

fibrous rings

Back 32

surround the orifices of the valves

Front 33

fibrous trigone

Back 33

formed by connections between rings

Front 34

coronary or atrioventricular groove

Back 34

separate the atria from the ventricles, (L. sulcus)

Front 35

anterior and posterior interventricular grooves

Back 35

separate the r. and l. ventricles

Front 36

apex beat

Back 36

where sounds of mitral valve closure is maximal

Front 37

base of the heart

Back 37

formed mainly by the left atrium

Front 38

anterior (sternocostal) surface of the heart

Back 38

formed by the right ventricle

Front 39

diaphragmatic (inferior) surface of the heart

Back 39

formed mainly by the left ventricle and partly by the right ventricle

Front 40

right pulmonary surface

Back 40

formed mainly by the right atrium

Front 41

left pulmonary surface

Back 41

formed mainly by the left ventricle, forms the cardiac impression of the left lung

Front 42

pulmonary trunk

Back 42

5 cm long and 3 cm wide, is the arterial continuation of the right ventricle and divides into r. and l. pulmonary arteries, conduct poorly oxygenated blood from the heart to the lungs

Front 43

right atrium

Back 43

receives blood from SVC, IVC, and coronary sinus (receives cardiac veins), interior contains:

-smooth, thin walled sinus venarum on which the venae cavae and coronary sinus open

-rough, muscular anterior wall composed of pectinate muscles

-right AV orifice through which blood is sent to the right ventricle

Front 44

right auricle

Back 44

conical muscular pouch that projects from this chamber like an add-on room, INC capacity of the atrium, overlaps the ascending aorta

Front 45

sulcus terminalis (or terminal groove)

Back 45

externally separate the smooth and rough parts of the atrial wall

Front 46

crista terminalis

Back 46

vertical ridge, internally separate the smooth and rough parts of the atrial wall

Front 47

interarterial septum

Back 47

separates the atria, has oval fossa (remnant of the oval foramen in the fetus)

Front 48

oval foramen

Back 48

helps shunt blood from the right atrium to the left atrium in the fetus, avoid the immature lungs

Front 49

right ventricle

Back 49

almost the entire inferior border of the heart, supplies blood to the lungs for oxygenation

Front 50

conus arteriosus

Back 50

infundibulum, leads into the pulmonary trunk

Front 51

trabeculae carnae

Back 51

irregular muscular elevations on the interior of the right ventricle

Front 52

supraventricular crest

Back 52

thick muscular ridge, separates the ridged muscular wall of the inflow part of the chamber from the smooth wall of the conus arteriosus (outflow part)

Front 53

right AV (tricuspid) orifice

Back 53

separates blood flow from the right atrium to the right ventricle, posterior to the body of the sternum at the 4th and 5th ICS,

Front 54

tricuspid valve

Back 54

guards the right AV orifice, bases of the valve cusps are attached to the fibrous ring, valve cusps prevent backflow of blood

Front 55

tendinous cords (chordae tendineae)

Back 55

attach to the free edges and ventricular surfaces of the anterior, posterior, and septal cusps, like the cords of a parachute, arise from the papillary muscles

Front 56

papillary muscles

Back 56

give rise to the chordae tendineae, circular muscular projections with bases attached to the ventricular wall, three types (anterior, posterior, septal), covered by enodcardium

Front 57

interventricular septum (IVS)

Back 57

composed of muscular and membranous parts, is a strong, obliquely placed partition between the right and left ventricles, is 2 to 3 times thicker on the side of the left ventricle

Front 58

septomarginal trabeculae (moderator band)

Back 58

curved muscular bundle that traverses the right ventricular chamber from the inferior part of the IVS to the base of the anterior papillary muscle, it carries part of the right branch of the AV bundle

Front 59

right branch of the AV bundle

Back 59

part of the conducting system of the heart to the anterior papillary muscle

Front 60

supraventricular crest

Back 60

deflects the incoming flow into the main cavity of the ventricle and the outflow into the conus arteriosus

Front 61

pulmonary valve

Back 61

at the apex of the consu arteriosus is at the level of the left 3rd costal cartilage

Front 62

left atrium

Back 62

most of the base of the heart, entry point for the valveless pairs of right and left pulmonary veins, interior has a larger smooth-walled part and a smaller muscular auricle containing pectinate muscles, and 4 pulmonary veins entering the smooth posterior wall, slightly thicker wall than that of the right atrium, an interatrial septum, and a left AV orifice through which the left atrium discharges the oxygenated blood it receives from the pulmonary veins into the left ventricle

Front 63

left auricle

Back 63

tubular and muscular, forms the superior part of the left border of the heart and overlaps the root of the pulmonary trunk

Front 64

left ventricle

Back 64

forms the apex of the heart, nearly all its left surface and border, and most of the diaphragmatic surface, performs more work than the right ventricle
-interior-walls that are two to three times thicker than that of the right ventricle, mostly covered by a mesh of trabeulae carnae, a conical cavity that is longer than that of the right ventricle, anterior and posterior papillary muscles that are larger than those in the right ventricle, aortic vestibule, and mitral valve (double leaftlet)

Front 65

aortic vestibule

Back 65

smooth walled, non-muscular outflow part leading to the aortic orifice and aortic valve

Front 66

aortic orifice

Back 66

beginning of ascending aorta

Front 67

mitral valve

Back 67

two cusps, receives tendinous cords from more than one papillary muscle

Front 68

semilunar aortic valve

Back 68

between left ventricle and the ascending aorta

Front 69

semilunar cupsps of the pulmonary valve and aortic valve

Back 69

three, concave when viewed superiorly, do not have tendinous cords attached to them, smaller in area than the AV valves, and force exerted on them is less than half exerted on the AV valves

Front 70

right aortic sinus

Back 70

the mouth of the right coronary artery

Front 71

left aortic sinus

Back 71

the mouth of the left coronary artery

Front 72

posterior arotic (non-coronary) sinus

Back 72

no artery arises from here

Front 73

coronary arteries

Back 73

the first branches of the aorta, supply the myocardium and epicardium, arise from the corresponding aortic sinuses, supply both the atria and the ventricles

Front 74

right coronary artery (RCA)

Back 74

passes to the right side of the pulmonary trunk, running in the coronary groove, usually gives off an ascending sinuatrial nodal branch and right marginal branch, RCA then turns to the left and continues to the posterior aspect of the heart, at the crux (junction of the septa and walls of the four heart chambers) the RCA gives rise to the atrioventricular nodal branch
-supplies: right atrium, most of the right ventricle, part of the left ventricle, part of the IV spetum, SA node (60% of people), and AV node (80% of people)

Front 75

sinuatrial nodal branch

Back 75

supplies the SA node, originates from the right coronary artery or arises from circumflex of LCA in 40% of people

Front 76

right marginal branch

Back 76

supplies the right border of the heart as it runs toward the apex of the heart

Front 77

atrioventricular nodal branch

Back 77

supplies the AV node

Front 78

posterior interventricular (IV) branch

Back 78

suppled by the RCA 67% of the time, descends down the posterior IV groove toward the apex, supplies both ventricles and sends perforating interventricular septal branches

Front 79

left coronary arter (LCA)

Back 79

arises from left aortic sinus of the ascending aorta, can give rise to the SA nodal branch, as it enters the coronary groove, divides into the anterior IV branch and the circumflex, lies between the pulmonary trunk and left auricle

-supplies: left atrium, most of the left ventricle, part of the right ventricle, most of the IVS, including the AV bundle, the SA node (40% of people)

Front 80

anterior IV branch

Back 80

passes along the IV groove to the apex, then it commonly anastomoses with the posterior IV branch, supplies adjacent parts of both ventricles, gives rise to a lateral branch, most common for coronary disease

Front 81

left marginal artery

Back 81

follows the left margin of the heart and supplies the left ventricle, usually terminates before crux but in 1/3 of people it runs to the posterior IV groove and gives rise to the posterior IV branch

Front 82

venous drainage of the heart

Back 82

drained mainly by veins that empty into the coronary sinus and partly by small veins that empty into the right atrium

Front 83

coronary sinus

Back 83

main vein of the heart, runs from right to left in the posterior part of the coronary groove

Front 84

great cardiac vein

Back 84

main tributary of the coronary sinus, its first part (anterior IV vein) beins near the apex and ascends with the anterior IV branch of the LCA

Front 85

middle cardiac vein (posterior IV vein)

Back 85

accompanies the posterior IV branch, drain areas supplied by the RCA

Front 86

small cardiac vein

Back 86

accompanies the right marginal branch of the RCA, drain areas supplied by the RCA

Front 87

anterior cardiac veins

Back 87

begin over the anterior surface of the right ventricle, cross over the coronary groove and usually end directly in the right atrium, sometimes entering the small cardiac vein

Front 88

smallest cardiac veins

Back 88

begin in the capillary beds of the myocardium and open directly into the chambers of the heart, may carry blood from the heart chambers to the myocardium, allow for collateral circulation (reversal of flow to brin luminal blood to the capillary beds of the myocardium, providing some additional collateral circulation)

Front 89

subepicardial lymphatic plexus

Back 89

lymph in the myocardium go here, pass to the coronary groove and follow the coronary arteries

Front 90

inferior trachobronchial lymph nodes

Back 90

end point for cardiac lymph nodes

Front 91

sinuatrial (SA) node

Back 91

located anterolaterally just deep to the epicardium at the junction of the SVC and right atrium, small collection of nodal tissue, specialized cardiac muscle fibers and associated fibroelastic CT, pacemaker of the heart, initiates and regulates the impulses for contraction, impulse of 70 times/min., stimulated by symp. and inhibited by parasymp., sends impuls right and left (to atrium)

Front 92

atrioventricular (AV) node

Back 92

smaller than the SA node, located in the posteroinferior region of the interatrial septum near the opening of the coronary sinus, receives impulse from the SA node, then distributes the impulse to the ventricles through the AV bundle, stimulated by symp. and inhibited by the parasym.

Front 93

right and left bundles of the AV bundle

Back 93

split at the junction of the membranous and muscular parts of the septum

Front 94

subendocardial branches (purkinje fibers)

Back 94

extend into the walls of the respective ventricles, coarse to moderator band

Front 95

cardiac plexus

Back 95

autonomic nerve fibers that supply the heart

Front 96

superior mediastinum

Back 96

superior to the transverse thoracic plane, contain thymus, great vessels, inferior continuation of the cervical viscera and related nerves, thoracic duct and lymphatic trunks

Front 97

thymus

Back 97

a lymphoid organ, located in the inferior part of the neck and the anterior part of the superior mediastinum, veins of the thymus end in the left brachiocephalic, internal thoracic, and interior thyroid veins, the lymphatic vessels of the thymus end in the parasternal, brachiocephalic, and trachobronchial lymph nodes

Front 98

left brachiocephalic vein

Back 98

union of the internal jugular and subclavian veins, more than twice as long as the righ bec. it passes from the left to the right side, passing over the anterior aspects of the roots of the three major branches of the arch of the aorta, shunts blood from the head, neck and left upper limb to the right atrium

Front 99

superior vena cava

Back 99

returns blood from all structures superior to the diaphragm except the lungs and heart, ends at the level of the 3rd costal carilage, right side o fthe superior mediastinum

Front 100

right phrenic nerve

Back 100

lies between the SVC and the mediastinal plura,

Front 101

ascending aorta

Back 101

begins at the aortic orifice, only branches are the coronary arteries

Front 102

arch of the aorta

Back 102

curved continuation of the ascending aorta, ends by becoming the thoracic aorta

-branches: brachiocephalic trunk, left common arotid artery and left sublclavian artery

Front 103

ligamentum arteriorsum

Back 103

remnant of fetal ductus arteriosus, passes from the root of the left pulmonary artery to the inferior surface of the arch of the aorta

Front 104

brachiocephalic trunk

Back 104

first and largest branch of the arch of the aorta, divides into the right common carotid and right subclavian arteries), only one, on the right side

Front 105

left common carotid artery

Back 105

second branch of the arch of the aorta, enters the neck by passing posterior to the left SC joint, right common carotid comes from brachiocephalic while left comes from aorta

Front 106

left subclavian artery

Back 106

third branch of the arch, comes from the aorta not from the brachiocephalic

Front 107

vagus nerve (superior mediastinum)

Back 107

exits the cranium and descend through the neck posterolateral to the common carotid arteries

Front 108

right vagus nerve

Back 108

enters the thorax anterior to the right subclavian artery, gives rise to the right recurrent laryngeal nerve

Front 109

recurrent laryngeal nerve

Back 109

hooks around the right subclavian artery and ascends between the trachea and esophagus to supply the larynx, associated with the ligamentum arteriosum (used to be ductus arteriosum)

Front 110

phrenic nerves

Back 110

supply the diaphragm with motor and sensory fibers, the latter accounting for approx. 1/3 of the nerve’s fibers, also supply sensory fibers to the pericardium and mediastinal pleura, enters the superior mediastinum between the subclavian artery and the origin of the brachiocephalic vein

-arise from cervical spinal nerves (C3-C5 contribute to the formation of the phrenic nerve), C3, 4, and 5 keep the heart alive

Front 111

right phrenic nerve

Back 111

passes along the right side of the right brachiocephalic vein, SVC, and pericardium

Front 112

left phrenic nerve

Back 112

descends between the left subclavian and left common carotid arteries,

Front 113

trachea

Back 113

descends anterior to the esophagus and enters the superior mediastinum, inclining a little to the right of the median plane

Front 114

esophagus

Back 114

extends from the pharynx to the stomach, enters the superior mediastinum between the trachea and the vertebral column

Front 115

posterior mediastinum

Back 115

contains the thoracic aorta, thoracic duct and lymphatic trunks, posterior mediastinal lymph nodes, azygos and heiazygos veins and esophagus and esophageal nerve plexus

Front 116

thoracic aorta

Back 116

continuation of the arch of the aorta

Front 117

thoracic aortic plexus

Back 117

autonomic nerve network that surrounds the thoracic aorta

Front 118

thoracic duct

Back 118

lies on the anterior aspect of the bodies of the inerior 7 thoracic vertebrae, it is the largest lymphatic channel in the body, conveys most lymph of the body to the venous system, originates from the chyle cistern in the abdomen, usually thin walled and dull white, ascends in the posterior mediastinum w/ the thoracic aorta on its left and the aygos vein on its right, often receives the jugular, subclavian, and bronchomediastinal lymphatic trunks, empties into the venous system near the union of the left internal jugular and subclavian veins

Front 119

azygos system of veins

Back 119

on each side of the vertebral column, drains the back and thoracoabdominal walls as well as the mediastinal viscera, arches over primary bronchus

Front 120

azygos vein

Back 120

forms a collateral pathway between the SVC and IVC and drains blood from the posterior walls of the thorax and abdomen, ascends in the posterior mediastinum, communicates with the vertebral venous plexuses that drain the back, vertebrae, and structures in the vertebral canal, also receives the mediastinal, esophageal, and bronchial veins

Front 121

hemiazygos vein

Back 121

arises on the left side by the junction of the left subcostal and ascending lumbar veins, goes to T9 vertebra, here it crosses to the right, posterior to the aorta, and joins the azygos vein, receives the inferior three posterior intercostal veins, the inferior esophageal veins, and several small mediastinal veins

Front 122

accessory hemiazygos vein

Back 122

begins at the medial end of the 4th or 5th ICS and descends on the left side of the vertebral column from T5 through T8, receives tributaries from veins in the 4th-8th ICS, crosses over the T7 or T8 vertebrae posterior to the aorta where it joins the azygos vein, sometimes joins the hemiazygos vein

Front 123

thoracic sympathetic trunks

Back 123

continuity with the cervical and lumbar symp. trunks

Front 124

lower thoracic splanchnic nerves (greater, lesser, and least)

Back 124

part of the abdominopelvic splanchnic nerves, supply viscera inferior to the diaphragm, presynaptic fibers from 5th through the 12th sympathetic ganglia

Front 125

anterior mediastinum

Back 125

smallest subdivision of the mediastinum, lies between the body of gthe sternum and the transverse thoracic muscles anteriorly and the periocardium posteriorly, consists of loose connective tissue (sternopericardial ligaments)

Front 126

pericardiophrenic artery and vein

Back 126

innervate the heart, branch of the internal thoracic artery

Front 127

crista terminalis

Back 127

prominent ridge where the pectinate muscles end

Front 128

Bundle of His

Back 128

bundle of conduction tissue that leaves the node and passes through the fribrous skeleton and enter ventricle region, only electrical connection between the atria and ventricle, splits into two (left and right), r descends down right ventricular septum and spreads out that radiate out to the right ventricular branches, purkinje fibers (the terminal filaments), Left bundle branch, splits very quickly into 5 or 6 branches, stimulate myocytes of the left heart to contract, called pukinje fibers as well

Front 129

placement of stethoscope for valves

Back 129

-aortic-right 2nd ICS, lateral to sternum

-pulmonary-left 2nd ICS, lateral to sternum

-tricuspid-left 4th ICS, lateral to sternum

-mitral-5th ICS, lateral to costal cartilage