Anatomy Middle Mediastinum Flashcards
Contents of the middle mediastinum
Heart
Pericardium
Components of the pericardium
Fibrous pericardium
Serous pericardium
Fibrous pericardium is a dense connective tissue ___ shaped bag with its base sitting on the ___ (attached by ___) and its apex is continuous with the ____.
It is connected to the sternum via ___
- cone
- diaphragm (connected by pericardiacophrenic ligament)
- adventitia of the great vessels
- sternopericardial ligaments
The serous pericardium forms a closed sac with 2 layers:
Parietal-fused with fibrous pericardium
Visceral-fused with the heart (in histology it is called the epicardium)
The pericardial cavity is a closed space between ____ which contains ___
- The parietal and visceral layers of the serous pericardium
- A thin layer of fluid
If there is excess fluid in the pericardial cavity it is called ___, which typically results from ____. As the outer fibrous pericardium is composed of dense CT, the accumulation of fluid in the pericardial cavity causes compression of ____, which can result in ____. The treatment includes a surgical procedure with aspiration of the fluid, called ____. It is performed by inserting a needle into the ___ intercostal space in the area medial to the ___
- pericardial effusion
- inflammatory process caused by acute pericarditis
- the heart and cardiac tamponade
- biventricular heart failure
- pericardiocentesis
- 5th or 6th
- cardiac notch of the left lung
___ are subdivisions of the pericardial sac, formed by the reflections of the ____ around the ___
Pericardial sinuses
Serous pericardium
Greater vessels
Pericardial sinuses & locations
- Transverse-part of a pericardial sac posterior to ascending aorta and pulmonary trunk
- Oblique-J shaped cul de sac behind the heart surrounded by reflection of serous pericardium around right and left pulmonary v. and IVC
The transverse pericardial sinus has great significance to cardiac surgeons
During surgeries on the aorta or pulmonary trunk they can pass a finger through the sinus and cut through in order to stop circulation
The apex of the heart is the ___ which points ____ and is located ____.
*this is the area for ___
Left ventricle
Anterior, inferior, and left
5th intercostal space 7-9 cm from midline
*auscultating the mitral valve
Surfaces of the heart:
*pyramid shaped
- Sternocostal/anterior-mainly right ventricle
- Diaphragmatic/inferior-mainly left ventricle, partly right
- Left pulmonary-left ventricle
- Right pulmonary-right atrium
- Posterior/base-mainly left atrium, partly right.
Blood supply to and from the pericardium
Internal thoracic a - pericardiacophrenic a.
Same names for veins
The posterior surface (or base) of the heart is separated from the diaphragmatic surface by the ___
Coronary sinus and sulcus
Margins of the heart:
1. Inferior/acute
- formed by right ventricle and small part of left.
- Sharp boundary between anterior and diaphragmatic surfaces
Margins of the heart:
2. Obtuse
- formed mainly by left ventricle
- rounded boundary between sternocostal/anterior surface and left pulmonary surface
Margins of the heart:
3. Left
- formed by left ventricle and left auricle
- boundary between sternocostal/anterior surface and left pulmonary surface
Margins of the heart:
4. Right
- formed by right atrium
- boundary between sternocostal/anterior surface and right pulmonary surface
Layers of the heart wall
- External epicardium (formed by visceral layer of serous pericardium)
- Middle myocardium- muscle, thickest
- Internal endocardium-formed by endothelial lining and subendothelial CT, contains conducting system
There are two main external sulci that reflect the internal segmentation of the heart into 4 chambers:
- Coronary sulcus circles the heart and separates atria from ventricles
- Interventricular sulcus (on anterior and posterior sides of the heart)
The coronary sinus contains what?
Right coronary a.
Circumflex branch of left coronary a.
Coronary sinus
Small cardiac v.
The anterior interventricular sulcus contains what?
Anterior interventricular a.
Great cardiac v.
The posterior interventricular sulcus contains what?
Posterior interventricular a.
Middle cardiac v.
The atria have ___ walls while the ventricles have __
Thin
Thick
The ___ receives deoxygenated blood from the SCV and IVC and coronary sinus. It is then pumped to the ___, which pumps blood into the ____ which delivers the blood to the ___
Right atrium
Right ventricle
Pulmonary trunk
Lungs
The ___ receives blood from the 4 pulmonary veins and pumps it into the ___, which then pumps it into the ___
Left atrium
Left ventricle
Aorta for systemic circulation
The right atrium is divided into:
2 continuous spaces, sinus of vena cavae and atrium proper
Sinus of venae cavae is separated from the atrium proper externally by ___ and internally by ___.
Embryologically it is derived from ___
- The sulcus terminalis cordis (shallow verticals groove)
- Crista terminalis (muscular ridge)
- sinus venosus
___ empty into the sinus of venae cavae
IVC and SVC
The ___ receives blood from most of the cardiac veins and opens medially into the opening of the ___
Coronary sinus
IVC
Located in the ___ is the right atrioventricular orifice with the ___ valvle
Atrioventricular septum
Tricuspid
The ___ separates the right and left atria. It contains the ___ which has a prominent margin, called the ___
Interatrial septum
Fossa ovalis
Limbus fossa ovalis
The space anterior to the crista terminalis, including the right auricle, is called the ___. It’s walls are covered by. The right auricle is ___
Atrium proper
Musculi pectinati
Ear-like conical muscular pouch (also has musculi pectinati and is an additional space to store blood)
The ___ forms most of the anterior surface of the heart and a portion of the diaphragmatic surface. The larger ____is separated from the ____ by a muscular ridge, the ____.
Right ventricle
Inflow portion
Outflow portion
supraventricular crest
The right ventricle receives blood from the ___ through the ___, which contains the triscuspid valve. The walls of the inflow portion of the right ventricle have ____
Right atrium
Atrioventricular orifice
Trabeculae carneae
Three of the ___ form the papillary muscles, which have one end attached to the ___ and the other to the ___, which connect to the free edges of the ___
Traveculae carneae
Ventricular surface
Chordae tendineae
Cusps of the tricuspid valve
Papillary muscles:
Anterior
Posterior
Septal
The largest and most constant papillary muscle
Extent?
Anterior
From the anterior wall of the ventricle to the anterior and posterior valves of the tricuspid
This papillary muscle may consist of 1, 2 or 3 structures with some chordae tendineae arising directly from the ventricular wall.
Extent?
Posterior
Posterior ventricular wall to the posterior and septal valves of the tricuspid
The most inconsistent papillary muscle, it is either small or absent.
Extent?
Septal
To the septal and anterior valves of the tricuspid
The ___ forms a bridge between the base of the anterior papillary muscle and the interventricular septum. What does it do?
Septomarginal trabecula (moderator band)
- prevents the overdistenstion of the right ventricle
- carries the right limb of the AV bundle from the IV septum
The right atrioventricular orifice is ___ during ventricular contraction by the ___, which consists of ___, which are attached to ____ through ___.
- Closed
- Tricuspid valve
- 3 cusps/leaflets (anterior, posterior, septal)
- corresponding papillary muscles
- chordae tendineae
The base of each cusp of the tricuspid valve is secured to ___
The fibrous ring that surrounds the AV orifice
The ___ of the right ventricle has the conus arteriosus, which contains the ___. This area has smooth walls and is derived from the embryonic ___
Outflow tract
Pulmonary valve
Bulbus cordis
The pulmonary valve consists of 3 ___. Each of which forms a pocket-like sinus, which fills with blood after ___ and forces the cusps ___. This prevents ___.
- Semilunar cusps (left, right, anterior)
- ventricular contraction
- to close
- blood in the pulmonary trunk from refilling the right ventricle
The free, superior edge of each of the pulmonary cusps has a ___ portion and a ___ portion.
Middle, thickened portion (nodule)
Thin lateral portion (lunula)
___ is a congenital defect in which the tricuspid valve is displaced toward the apex of the heart
Ebstein’s anomaly
The ___ forms most of the base or posterior surface of the heart. Embryologically it consists of two parts ____ and ___ which are NOT physically divided by a crest.
Left atrium
Inflow portion and anterior portion
The ___ portion of the left atrium is the posterior portion and receives ___. It has ___ walls
Inflow
The 4 pulmonary veins
Smooth
The ___ portion of the left atrium is the atrium proper and contains the ___. Its walls have ___
Anterior portion
Left auricle
Pectinate muscles
The ___ of the left atrium is part of the anterior wall. It has a thin or depressed area, the ___ and is opposite the floor of the fossa ovalis in the right atrium.
Interatrial septum
Valve if the foramen ovale
The __ is the largest chamber of the heart and is ___ in shape. It contributes to what surfaces?
Left ventricle
Conical
-anterior, diaphragmatic left pulmonary surfaces
-forms the apex
The inflow portion of the left ventricle contains the ____. In the left ventricle the trabeculae carneae are ___ in contrast to those in the right ventricle. There are __ papillary muscles (___), which are ___ than those in the right ventricle. They are attached to the leaflets of the mitral valve by chordae tendinae.
- Left AV orifice with the mitral valve
- fine and delicate
- 2 (anterior, posterior)
- larger
The left AV orifice is ___ during ventricular contraction by the ___, which has ___
Closed
Mitral valve
2 cusps (anterior, posterior)
The outflow tract of the left ventricle has ___ walls and is derived from the embryonic ___
Smooth
Bulbus cordis
The opening from the left ventricle into the aorta is closed by the ___. It consists of ___
Aortic valve
3 semilunar cusps (left, posterior, right)
The sinus of the left semilunar cusp of the aortic valve contains ___. Right contains ___??
Opening of left coronary a.
Opening of right coronary a.
The interventricular septum consists of 2 parts:
- Muscular-thick, major part of septum
2. Membranous-thin, upper part of septum
Two coronary arteries arise from ___ and supply the ___
- The aortic sinuses in the ascending aorta
- muscles and other tissues of the heart
The right coronary a. originates from the ___ and supplies the ___. It passes ___ between the ___ and the ___.
Right aortic sinus of the ascending aorta
- right atrium and right ventricle, the SA and AV nodes, and the internal septum
- anteriorly between the right auricle and pulmonary trunk
Branches of the right coronary a.
- SA nodal branch
- Right marginal branch
- Posterior interventricular branch
- AV nodal branch
The ___ of the right coronary a. passes posteriorly and around the SVC
SA nodal branch
The ___ is given off as the right coronary a. approaches the inferior (acute) margin of the heart and continues along this border toward the apex of the heart
Right marginal branch
The ___ is the continuation of the right coronary a. onto the posterior surface of the heart, where it lies in the posterior interventricular sulcus
Posterior interventricular branch
The right coronary a. gives rise to the ____ at the junction of the interatrial and interventricular septa between the four heart chambers
AV nodal branch
The left coronary a. originates from the ___. It passes between the ___ and the ___.
- left aortic sinus of the ascending aorta
- pulmonary trunk and left auricle
Branches of the left coronary a.
- anterior interventricular branch (LAD)
a. Diagonal branch - circumflex branch
a. Left marginal a.
The ___ of the left coronary a. continues around the left side of the pulmonary trunk and descends obliquely toward the apex of the heart in the anterior interventricular sulcus
Anterior interventricular branch (LAD)
The ___ branch of the LAD takes off at the mid-level of the left ventricle to supply the left ventricular wall
Diagonal
The ____ branch of the left coronary a. Courses toward the left within the coronary sulcus and into the base/diaphragmatic surface of the heart
Circumflex
The ____ branch of the left coronary a. usually arises from the circumflex a. and continues across the rounded obtuse margin of the heart
Left marginal a.
Variations of the coronary arteries
Most common is the right dominant pattern:
- posterior interventricular branch begins from RCA
- in 15% of others it begins from the circumflex a. of the LCA
- second most common variation is where it originates from the SA nodal branch
Coronary a. disease:
Sudden occlusion of one of the major coronary arteries causes the infarction of the corresponding myocardium and consecutive necrosis
The most common sites of coronary a. occlusion are:
- LAD branch of LCA (widow-maker)
- RCA
- Circumflex branch of LCA
Most of the cardiac veins empty into the ___, which receives 4 major tributaries:
Coronary sinus
-great, middle, small, and posterior cardiac veins
The ___ begins at the apex of the heart and ascends through the anterior interventricular sulcus, where it is often termed the ____. It then reaches thecoronary sulcus where it is associated with the circumflex branch of the LCA. It gradually enlarges and then enters the ___
Great cardiac v.
Anterior interventricular v.
Right atrium
The ___ (aka ___) begins near the apex of the heart and ascends within the posterior interventricular sulcus towards the coronary sinus
Middle cardiac v.
Posterior interventricular v.
The ___ (aka ____) begins at the lower anterior section of the coronary sulcus between the right atrium and right ventricle and accompanies the marginal branch of the RCA along the ___ of the heart
Small cardiac v.
Right marginal v.
Acute margin
The ___ (aka ___) lies on the posterior surface of the left ventricle just to the left of the middle cardiac v. It either enters the coronary sinus directly or ___
Posterior cardiac v.
Left marginal v.
Joins the great cardiac v.
The SA node is located __
At the superior end of the crista terminalis at the junction of the SVC and right auricle
The AV node is located ___
Near the opening of the coronary sinus within the AV septum
Impulses in the heart begin in the ___, then travel to the ____ via ___
Atria due to SA node
ventricles via the AV bundle
The ___ is a direct continuation of the AV node. It follows along the lower border of the ____ before doing what?
Bundle of His
- Membranous part of the interventricular septum
- splitting into right and left bundle branches
Right vs left bundle branches
- right: goes to apex of right ventricle. Supplies ventricular muscles, including papillary muscles. Part of it passes through the moderator band (septomarginal trabecula)
- left: goes to apex of left ventricle.
The subendocardial plexus is found between the ___ and the ___.
It is formed by ____.
Endocardium and myocardium
Purkinje fibers
The preganglinic sympathetic fibers to the heart originate in the ____. They travel to sympathetic ganglion within the ___
Lateral horn of the gray matter from spinal levels T1-T4
-thoracic chain
The heart has pain nerve endings deep within the ___. The heart is insensitive to ___ but responds to ___
- Myocardium
- Touch, cutting, cold, heat
- ischemia and accumulation of metabolic products
Pain that originates in the heart is called ___, which usually appears as ___
Angina or angina pectoris
Transient moderately severe constricting pain as tightness in the thorax
