Chapter 7 - Pericardium and Heart Flashcards Preview

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Flashcards in Chapter 7 - Pericardium and Heart Deck (33)
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Features of fibrous pericardium

1. Made of fibrous tissue
2. Parietal layer of serous pericardium is attached to its deep surface
3. Blunt apex at level of sternal angle
4. Fused with roots of great vessels and pretracheal fascia
5. Broad base blended with central tendon of diaphragm
6. Connected to body of sternum by superior and inferior sternopericardial ligaments
7. Posteriorly, related to principal bronchi, oesophagus, and descending thoracic aorta
8. On sides, medistinal surface of lungs, phrenic N, pericardiacophrenic vessels
9. Protects the heart from sudden overfilling and prevents overexpansion


Features of serous pericardium

1. Double layered
2. Inner layer is fused with heart except along cardiac grooves
3. Parietal and visceral layers are continuous with each other at roots of great vessels
4. Space between parietal and visceral is called pericardial cavity
5. Pericardial cavity is filled with fluid for lubrication


Transverse sinus

-Horizontal gap between arterial and venous ends
A: Ascending aorta, pulmonary trunk
P: Superior vena cava
I: Left atrium
-Develops from degenration of central part of dorsal mesocardium


Oblique sinus

A: Left atrium
P: Parietal pericardium, oesophagus
Sides: Reflections of pericardium
-Opens into pericardial cavity below
-Permits free pulsation of left atrium
-Develops due to rearrangement of veins in venous end


Contents of pericardium

1. Heart
2. Cardiac vessels and N
3. Ascending aorta
4. Pulmonary trunk
5.Lower part of superior vena cava
6. Inferior vena cava
7. Pulmonary V


Blood supply of pericardium

1. Internal thoracic A
2. Musculophrenic A
3. Descending thoracic aorta


Nerve supply of pericardium

-Fibrous and parietal: Phrenic N, sensitive to pain
-Visceral: autonomic N, no pain
-Pain of pericarditis: from parietal pericardium
-Pain of angina: Cardiac muscles, vessels


Pericardial effusion

-Cardiac tamponade
-Collection of fluid in pericardal cavity
-Restriction of venous filling is seen
-Cardiac output decreases
-Drained at 5th/6th intercostal space just lateral to sternum


Mitral stenosis

Left atrium enlarges
Compresses oesophagus


Coronary sulcus

-Atrioventricular sulcus
-Right half of anterior part lodges right coronary A
-Left half lodges circumflex branch of left coronary A
-Overlapped anteriorly by ascending aorta and pulmonary trunk


Interventricular groove

-nearer to left margin
-runs downwards and left
-on inferior/diaphragmatic surface
-nearer to right margin


Apex of heart

-Formed entirely by left ventricle
-Directed downwards, forward, to left
-Overlapped by anterior border of lung
-At 5th intercostal space


Base of heart

-Also called posterior surface
-Mainly left atrium
-Openings of 4 pulmonary veins and vena cavae
-Related to T5-T8
-Separated from vertebral column by pericardium, pulmonary V, oesophagus and aorta


Borders of the heart

Upper: Oblique, mainly by left atrium
Right: Vertical, right atrium, from SVC to IVC
Inferior: Horizontal, mainly right ventricle, IVC to apex
Left: Oblique and curved, mainly left ventricle, apex to left auricle


Sternocostal surface

-Formed mainly by right atrium and ventricle
-Mostly covered by lungs except at cardiac notch
-Uncovered part is dull in percussion--area of superficial cardiac dullness


Diaphragmatic surface

-Rests on central tendon of diaphragm
-Left 2/3 - Left ventricle
Right 1/3 - Right ventricle
-Traversed by posterior interventricular groove


Left surface

-Mainly by left ventricle and auricle
-Crossed by coronary sulcus
-Related to left phrenic N, left pericardiacophrenic vessels, pericardium


Right atrium forms

1. Right border
2. Part of upper border
3. Sternocostal surface
4. Base of heart


External features of right atrium

1. Vertically elongated
2. Receives SVC and IVC
3. Upper end forms right auricle
4. Shallow vertical groove from SVC to IVC -- sulcus terminalis produced by muscular ridge crista terminalis
5. Right atrioventricular groove lodges right coronary A and small cardiac V


Right auricle

-Covers root of ascending aorta and infundibulum of right ventricle
-Margins are notched
-Sponge like interior to prevent free blood flow


Inlets of right atrium

1. SVC and IVC
2. Coronary sinus
3. Anterior cardiac V
4. Thebesian V
5. Right marginal V


Interior divisions of right atrium

1. Sinus venarum - smooth posterior part
2. Pectinate - rough anterior part
3. Interatrial septum


Sinus venarum

-Derived from right horn of sinus venosus
-SVC, IVC, coronary sinus and thebesian V open into it
-Opening of IVC is guarded by rudimentary Eustachian valve
-Opening of coronary sinus is guarded by thebesian valves
-Intervenous tubercle of Lower is a projection just below opening of SVC to direct blood into right ventricle in IUL


Pectinate part

-Derived from primitive atrial chamber
-Has transverse muscular ridges called musculi pectinati
-They arise from crista terminalis
-The run towards the atrioventricular foramen


Interatrial septum

-Derived from septum primum and septum secondum
-Fossa ovalis is seen
-Annulus ovalis is the margin of fossa ovalis.
Represents lower free edge of septum secondum.
Anteriorly it is continuous with valve of IVC


Right ventricle forms

1. Inferior border
2. 2/3 sternocostal surface
3. 1/3 inferior surface


Features of coronary arteries

1. Blood flows during diastole
2. 1.5-5.2 nm diameter
3. Left is larger and supplies to most of myocardium
4. Functional end arteries. Anastamoses cannot compensate during thrombosis
5. Origin of posterior interventricular A determnes dominance


Origin and course of right coronary A

- From anterior aortic sinus
- Emerges b/w pulmonary trunk and right auricle
- Runs in right anterior coronary sulcus
- Reaches diaphragmatic surface
- Runs in right posterior coronary sulcus
- Reaches posterior interventricular groove
- Anastamoses with circumflex branch of left coronary A


Branches of right coronary A

1. Atrial: anterior, posterior, lateral--supply SA node
2. Right conus- forms ANNULUS OF VIEUSSENS around pulmonary trunk with left conus
3. Ventricular: anterior, posterior
4. Right marginal- runs along inferir margin till apex
5. Posterior interventricular- suplies AV node


Area of distribution of right coronary A

1. Right atrium
2. Greater part of right ventricle
3. Small part of left ventricle
4. Posterior 1/3 of IV septum
5. Whole of conducting system