Surface anatomy of mediastinum and structure of heart Flashcards
Trans thoracic plane
Divide mediastinum into superior and inferior - horizontal line runs through manubirosternal joint at level of T4
What is the mediastinum
The central compartment or a median septum between the two pleural cavities within the thoracic cavity
contains visceral structures - air of fluid filled united by loose connective tissue
what are the boundaries of the mediastinum
superior thoracic aperture/outlet superiorly and diaphragm inferiorly
sternum and costal cartilages anteriorly to thoracic vertebrae posteriorly
inferior mediastinum is subdivided into what
anterior
middle
posterior
what does the mediastinum contain
oesophagus trachea great vessels heart pericardium nerves sympathetic chain lymphatic vessels thoracic duct lymph nodes
is the diploid process in the mediastinum
no below inferior
in the supine position the mediastinum - arch of the aorta lies superior to the transverse thoracic plane and bifurcation of the trachea is transected by the transverse thoracic plane. The central tendon on the diaphragm lies at the level od what
xiphersternal junction and vertebra T9
in the standing position the arch of the aorta is transected by the transverse thoracic plane and tracheal bifurcation lies inferior to thoracic plane to what level does the central tendon of the diaphragm fall to
level of the middle xiphoid process and T9-10 intervertebral discs
on chest X-ray the mediastinum can be shown to widen what 3 things could this be due to
haemorrhage into the mediastinum from lacerated great vessels
enlargement of the mediastinal lymph nodes due to a malignant lymphoma
hypertrophy of the heart due to congestive heart failure
what is the pericardium
a fibroserous membrane covering the heart and parts of the great vessels.
it is a closed sac made of 2 layers
fibrous and serous pericardium
the serous( internal) pericardium is made of two layers what are they
parietal layer
visceral layer
what are the two pericardial sinuses
transverse pericardial sinus
oblique pericardial sinus
what is the fibrous pericardium a continuation of
central tendon of diaphragm
prevents overfilling of the heart but can contribute to cardiac tamponade
what is the internal visceral layer that forms the outer layer of the heart called
epicardium
what is found between the inner and outer serous layers of the pericardial cavity
lubricatign serous fluid - minimises friction generated by the heart as it contracts
Fat police smell villains
fibrous , partial layer , serous fluid, visceral
4 major function of the pericardium
fixes the heart limiting motion
prevents overfilling
lubrication
protection from infection
what is the transverse pericardial sinus
formed as a result of embryological folding of the heart tube - passage through pericardial cavity
located posterior to ascending aorta and pulmaory trunk , anterior to SVC anf superior to LA
it separates the hearts atrial outflow from its venous inflow
it can be used to identify and subsequently locate the arteries of the heart during coronary artery bypass grafting
what nerve innervates the pericardium
phrenic nerve
where can pain be felt in pericarditis
shoulder
what is cardiac tamponade
inextinsible fibrous pericardium cause problem is pericardial effsusion as can’t expand therefore increasing pressure compremissign CO
pericarditis
inflammation of the pericardium , caused by infection and MI. Main symptom is chest pain, can cause acute cardiac tampiande due to accumulation of fluid in pericardial cavity
what is the oblique pericaral sinus
cul-du-sac behind heart which opens into pericardial space
what are the receiving chambers of the heart
RA and auricle
LA and auricle
what are the discharging chambers of the heart
RV and LV
what side of the heart receives poorly oxygenated blood
right
what is the purpose of the atrial auricles
atrial appendage is same name
increase capacity of atrium and also increase volume of the blood that it is able to contain
what are the 3 layers that make up the heart
endocardium
myocrdium
epicardium ( visceral pericardium )
what is the coronary sulcus
also called atrioventricular groove , groove separating the atria and ventricles
what do the anterior and posterior interventicualr sulci separate
ventricles
the apex of the heart is formed by the inferolateral part of the left ventricle where does it lie
5ht intercostal space about 9cm from the median plane
the base of the heart is formed by the right atria mainly and receives the pulmonary veins at its left atrial portion - what does it receive from its right atrial position
superior and inferior venae cavae
apex and base different
Anterior (sternocostal) – right ventricle (mainly)
Diaphragmatic (inferior)- left (mainly) and right ventricle
Right pulmonary – right atrium (mainly)
Left pulmonary – left ventricle (mainly)
four surfaces of the heart
four borders
Right – right atrium, extends between SVC and IVC
Inferior – right (mainly) and left ventricle
Left – left ventricle (mainly) and left auricle
Superior – right and left atria and auricles.
landmarks for border of the heart depend on position of diaphragm and the physical condition of the individual
where is the superior borer
From the inferior border of the 2nd left costal cartilage to the Superior border of the 3rd right costal cartilage, 1 - 2cm from the margin of the sternum on each side.
right border of the heart
From the 3rd right costal cartilage to the 6th right costal cartilage – slightly convex to the right, 1 - 2cm from the margin of the sternum on each side.
inferior border of the heart
From the inferior end of the right border to a point in the 5th intercostal space close to the midclavicular line – apex of the heart/apex beat.
left border of the heart
A line connecting the lefts ends of the superior and inferior borders.
what is the fibrous skeleton of the heart
A complex framework of dense collagen fibres that form four rings around the orifices of the cardiac valves.
3 functions of the fibrous skleeton of the heart
Provides structural foundation of the heart valves – keeps patent and prevents overstretching.
Anchors the myocardium.
Acts as electrical insulator between the atria and ventricles.
what is the sinus venarum ( sinus of the vena cavae)
thin walls from right sinus horn that connects below right ventricle and medially with LA
function of pectate muscles - primitive atrium
increasing power of contraction without increasing heart mass
what is the right atrioventricular orifice
is a large oval aperture of communication between the right atrium and ventricle situated at base of atrium about 4cm wide
what is the crust terminalis
thick heart muscle on external aspect of right atrium - terminal sulcus - spertaes between the smooth and rough parts
oval fossa is what
remnant of oval foramen
what feature is a coinical such formed from the upper and left angle of right lenticel n the chordate heart - from which the pulmonary trunk arises - delves from bulbs cordis
infundibulum
the trabecular carneae
muscular columns project from inner ventricles - different from pectinate muscles which are found in atria
supraventricular crest separates the trabeculated and smooth wall parts and as important function in guiding blood flow - true or false?
true
three cusps of tricuspid valve
anterior
posterior
septal
papillary muscles attach to what
atrioventricular valves via chordae tendineae and contract to prevent inversion of prolapse of these valves on systole ( ventricular contraction
intraventicualr septum separates what
ventricles
the moderator band know as septomarginal trabecula is a band of cardiac muscle in RV carries part of what
branch of AV bundle of His
the pumaory valve has semilunar cusps what are they
anterior
right
left
mitral valve has 2 cusps what are they
anterior and posterior
the aortic valve has semilunar cusps what are they
poster right and left
right coronary artery has many perforating interventicualr spatial branches what is the dominant right coronary artery with 67%
poster inter ventricular ( poster for descending) artery
left coronary artery from the LAD which gives rise to what branches
interventrciualr septal branches
lateral ( diagonal) artery
Circumflex artery - sine-atrial nodal artery and left marginal artery
the RCA supplies what
RA most of ventricle part of LV ( diaphragmatic surface) part of interventricualr septum) SA node - 60% cases AV node -80%
the LCA supplies what
LA most LV part of RV most of interventicualr septum SA node - 40%
where are the
Cardioacceleratory (pressor) centre – Sympathetic.
Cardioinhibitory (depressor) centre – Parasympathetic.
located
medulla oblongata
what increases the rate and force of contractions
Sympathetic fibres through the cardiac plexus to the SA and AV nodes, cardiac muscles and coronary arteries.
what fibres slow the heart
Parasympathetic fibres through the cardiac plexus to the SA and AV nodes, cardiac muscles and coronary arteries.
Afferent parasympathetic fibres run with the Vagus nerve and are concerned with cardiac reflexes (Baroreceptor, Aortic arch and Carotid sinus reflexes for blood pressure homeostasis).
do afferent sympathetic fibres go to T1,2-4 - referring pain here across chest and upper limbs ?
yes
where are the sounds of the heart best heard
The valves of the heart are located deep to the sternum. The sounds of the heart and great vessels are best heard superficial to the chamber or vessel into which the blood has passed, and in a direct line with the valve in the direction of blood flow.
where can you find he pulmaory valve
Pulmonary Area:
the sternal end of the 1st or 2nd left intercostal space.
where can you listen to arctic valve
Aortic Area:
The sternal end of the 1st or 2nd right intercostal space.
where can you listen to mitral valve
Mitral Area:
Near the apex of the heart in the 5th left intercostal space.
where can you listen to tricuspid valve
the sternal edge at the level of the 4th or 5th intercostal space right or left of the sternum.
where can you listen to aortic valve
aortic area is found second right intercostal space
when can you listen to the pulmonary valve
pulmonic area is second left intercostal space
where can you listen to the mitral valve
the mitral area or apex is the 5th left intercostal space in the midclavicual line
where can you listen to the tricuspid valve
this area is found in the fourth tnerocstalspace in the left lower sternal border
where is erbs point
third left intercostal space ( left sternal border)
5th point of auscultation -hear both sounds S1 from closure of mitral and tricuspid and S2 from closure or aortic and pulmonary valves
what Is the role of the aortic sinuses
The aortic sinuses are small openings found within the aorta behind the left and right flaps of the aortic valve. When the heart is relaxed, the back-flow of blood fills these valve pockets, therefore allowing blood to enter the coronary arteries.
