3 - The heart and mediastinum Flashcards
The transverse thoracic plane is the horizontal plane from
the sternal angle (2nd rib level) to the intervertebral disc of T4-T5 vertebrae , which divides _____ mediastinum from
________ mediastinum
Superior; posterior
Name the 8 notable structures at the level of the transverse thoracic plane.
RATPLANT
- Rib 2
- Arch of aorta
- Trachea bifurcation
- Pulmonary trunk
- Ligamentum arteriosum
- Azygous vein enters SVC
- Nerves: left recurrent laryngeal nerve, cardiac plexus, sympathetic trunk
- Thoracic duct crosses from the right to the left (not happen in asians)
Branches of the aorta?
"ABCS" Aorta Brachiocephalic trunk left common Carotid artery left Subclavian vein
What are the 4 main structures present in the superior mediastinum?
- Thymus
- Great vessels:
- ABCS, SVC - Trachea and its main branches
- tracheobronchial lymph nodes - Nerves:
- Phrenic nerves
- Vagus nerves
- Left recurrent laryngeal nerve
What are the 5 main structures present in the posterior mediastinum?
- Esophagus
- Thoracic aorta and intercostal arteries
- Azygous and hemiazygous veins
- Nerves
- Parasympathetic: vagus nerve (esophageal and cardiac plexus)
- Sympathetic: Sympathetic trunk, splanchnic nerves (greater and lesser) (SSS) - Lymphatics: Thoracic duct (posterior to esophagus)
The middle mediastinum contains:
Heart and pericardium
The 2 pericardium that the heart has are:
- Serous pericardium
(inner, visceral and parietal layers) - Fibrous pericardium (outer)
What are the 2 sinuses of the heart? What are their clinical correlations?
- Transverse pericardial sinus
- space behind the
aorta and pulmonary trunk
- By passing a surgical clamp, can stop or divert the
circulation of blood in these large arteries while
performing cardiac surgery - The oblique pericardial sinus
- space behind the heart
within the pulmonary veins.
If your finger is put in the transverse pericardial sinus, what are the structures anteriorly and posteriorly?
Anterior: Ascending aorta and pulmonary trunk
Posterior: Arch of aorta
(can refer to notes for a diagram)
What is pericarditis?
What is the treatment of it?
Pericarditis is the inflammation of the serous pericardium, causing accumulation of fluid in the pericardial cavity which compresses on the heart (cardiac tamponade)
Treatment:
Pericardiocentesis
- drawing fluid /blood accumulated in the pericardial cavity.
What are the borders of the heart? (4!)
Superior: Root of great vessels
Right border: RA, IVC, SVC
Left border: LV, apex of heart
Inferior border: Diaphragmatic surface of the heart
What are the 3 surfaces of the heart? What structures are located there respectively?
Anterior surface:
RA, RV (mostly), LV, atrioventricular groove (RA,RV) = coronary sulcus, anterior interventricular sulcus (LV,RV)
Inferior surface (Diaphragmatic) : LV (most), RV, posterior interventricular sulcus, (with the apex)
Posterior surface:
RA, LA, origin of great vessels
The posterior interventricular sulcus separates the left
and right ventricles on the posterior side, it contains the
____________ artery and the ________ vein.
Posterior interventricular;
Middle cardiac vein
The anterior interventricular sulcus separates the left and
right ventricles on the anterior side, it contains the___________artery and the ___________ vein
Anterior interventricular;
Great cardiac vein
The papillary muscles are muscle projections with one end attaching to the ________ and the other end to ________.
ventricular wall;
Chordae tendineae
____________ a network structure forming an elevated platform: papillary muscles are examples of them
Trabeculae carneae
The right atrium receives blood from:
SVC, IVC, coronary sinus
In the atria, the appendages projects from the atrium like an add-on room, and are with _________ muscles.
pectinate muscles
The crista terminalis
A. the junction between the sinus venosus and the heart in the developing embryo.
B. is a smooth muscular ridge that separates the rough part and smooth part of the right atrial wall
C. provides the origin for the pectinate muscles
All
B: Rough part: presence of pectinate muscles
Auricle refers to ___________.
the space within the atrial
appendage
The AV node is on the septum and located near the opening of the ___________.
coronary sinus
Fossa ovalis locates on the __________. It is equivalent to the _________ of the fetal heart.
Atrial septum;
foramen ovale
_________ is the pacemaker of the heart.
SA node (sinoatrial node)
Valves are present at the openings of the ____ and _______ into the right atrium.
IVC and coronary sinus.
but not the SVC
What are the actions of the papillary muscles when blood flow from RA to RV?
The papillary muscles begin to contract before contraction of right ventricle, pulling on chordae tendineae, preventing the tricuspid valves from being driven into the right atrium.
______________ carries
conducting tissue to the papillary muscles so papillary
muscle contracts earlier than the right ventricle
Moderator band
only in RV!
The _______ is the superior part of the right ventricle. It
is cone-shaped and leads into the pulmonary trunk
Infundibulum
Where are the SA node and AV node specifically?
SA node: entrance of SVC, right atrium, superior end of cristae terminalis
AV node: within the Koch’s
triangle , the triangle with borders formed by the coronary sinus orifice , septal leaflet of tricuspid valve and fossa ovale
The left atrium receives blood from __________.
Pulmonary veins
__________ locates posteriorly to the left atrium
Esophagus
Behind the left cusp and right cusp of the aortic valves, are
holes on the wall. These holes lead to the ______ and _________.
left coronary artery and right coronary artery
Opening and closing of valves is ALWAYS driven by
__________ of the two sides of the valve
the pressure difference
The left ventricle has A. the thickest wall B. Trabeculae carneae C. papillary muscles with cordae tendineae D. Mitral valves and aortic values
All
Atrioventricular valves (tricuspid, mitral): close during __________ to prevent blood backflow from ventricles to atria
ventricular systole or constriction
__________ close during ventricular diastole or dilation to prevent blood backflow from arteries to ventricles; cusps of aortic valves – origins of coronary arteries
Arterial (pulmonary, aortic) valves
What is the mnemonic to remember the arteries supplying the heart?
○ Form a fist with the left hand, place left fist anterior to heart. Fingers represent the position and direction of
blood vessels
○ Left coronary artery indicated by thumb and index finger
■ Thumb: circumflex artery (curls to the
posterior side of heart)
■ Index finger: anterior IV branch (runs inferiorly)
○ Pinky finger: Right coronary artery (runs inferiorly)
Heart valve diseases:
___________ : failure to open valve completely > impeding flow from atrium to ventricle
Stenosis
Heart valve diseases:
__________: failure to close valve completely > backflow of blood from ventricle to atrium
Incompetence
What are the 2 ○ Mitral (bicuspid) valve diseases?
Mitral stenosis (narrowing) Mitral regurgitation (incompetence)
What are the 2 Aortic valve diseases?
§ Aortic stenosis (narrowing) Aortic regurgitation (incompetence)
Both Right and left coronary arteries arise from _____________.
State the vessel pathway from right coronary artery and left coronary artery respectively.
the cusps of the aortic valves;
Pathway:
Right coronary artery:
SA node artery> Right marginal artery > posterior interventricular artery* > AV node artery
Left coronary artery:
Anterior interventricular artery* > circumflex artery > left marginal artery
Just remember the *
What is the mnemonic to remember the veins draining the heart?
○ Form a “6” (fist with thumb and pinky finger pointing
out) with the right hand, place right hand posterior to
heart. Align knuckles on coronary sinus
○ Thumb ( greatest finger): Great cardiac vein (runs
laterally to the left)
○ Index finger: Left marginal vein (runs toward the
apex)
○ Middle finger: Posterior ventricular vein (runs
toward the apex)
○ Ring finger: Middle cardiac vein (runs toward the
apex)
○ Pinky finger (the smallest finger): Small cardiac vein
(runs laterally to the right)
The great cardiac vein runs along the _______
artery and _______ artery (arteries of the left coronary
artery) in an L-shape and drains into the ____________.
Anterior interventricular artery;
Circumflex artery;
Coronary sinus
The middle cardiac vein runs along the _______.
posterior
interventricular artery
The small cardiac vein runs along the _______.
right marginal artery
○ Great cardiac vein drains the areas supplied by the
_______________
○ Middle and small cardiac veins drain areas supplied
by the ______________.
Left coronary artery;
Right coronary artery
Which of the following about Sympathetic actions on the heart is/are correct?
A. Thoracolumbar outflow (T1-L2/L3 B. by sympathetic trunk C. Cranosacral outflow D. 4 cranial nerves: 3,7,9,10 E. S2-4 sacral nerves F. increases contraction of cardiac muscle and heartbeat G. Dilates the coronary vessels
A,B,F,G
C,D and E are parasympathetic
*Parasympathetic action:
decrease heartbeat, constricts coronary vessels
__________ is where blood flows from the right atrium (the higher pressure side in foetus) to the left atrium, bypassing the pulmonary circuit (fetal lungs are of high vascular resistance).
A patent foramen ovale (when the interatrial septum fails to close) results in a congenital condition named ___________.
Foramen ovale;
atrial septal defect
Conducting system of the heart:
SA node generates impulses to stimulate:
(use a flow chart)
atrial myocardium
> AV node
> bundle of His
> left and right bundle branches to ventricular myocardium
Referred pain: Site of damage - Dermatomes referred to A. diaphragm B. heart C. gall bladder D. stomach E. Appendix
A. C 3-4 B. T 1-4 (left) C. T 7-8 (right) D. T 6-9 (left) E. T 10
Sympathetic trunk consists of
paired nerve bundles.
The paired referred to ______ and ______ that supplies the ________________________ and ___________________ respectively.
- Upper fibers: thoracic viscera (esophagus, heart)
- Lower fibers: Splanchnic nerves (abdominal and pelvic viscera)
3 divisions of the splanchnic nerves are:
List the vertebral level too
- Great splanchnic nerve (T5-T9)
- Lesser splanchnic nerve (T10-11)
- Least splanchnic nerve (T12)
Vagus nerves give branches to the _____, ______ and _______ plexuses (*parasympathetic)
esophageal, cardiac and pulmonary
The right vagus nerve gives rise to __________________ which loops under the ___________.
right recurrent laryngeal nerve;
right
subclavian artery
The left vagus nerve gives rise to__________________ which passes posterior and
lateral to the ____________ under the ___________.
left recurrent laryngeal nerve;
Ligamentum arteriosum;
aortic arch
Both recurrent branches of the vagus nerve innervate the ________.
Larynx
The ligamentum arteriosum is the ___________
before birth. The _______ (same) acts as a shunt so blood in pulmonary trunks can bypass the lungs (gaseous exchange occurs in the placenta in foetus) and enters the aorta directly.
ductus arteriosus
○ Mnemonic: Note the consistent ending letters
○ Ligamentum arteriosum
○ Ductus arteriosus
extra:
○ Foramen ovale → fossa ovale
○ Duct us arterios us → ligament um arterios um
○ Duct us venos us → ligament um venos um
○ The first two function to bypass lungs, while the third
bypasses liver
Summary of fetal circulation (just before birth):
placenta → umbilical vein (ligamentum teres hepatis)
→ ductus venosus (ligamentum venosum) →
inferior vena cava → right atrium → through foramen
ovale (fossa ovale) → left atrium → left ventricle →
ascending aorta → upper part of body (well
oxygenated blood to brain) → superior vena cava →
right atrium → right ventricle → pulmonary trunk →
ductus arteriosus (ligamentum arteriosum) →
descending aorta → lower part of body (less
oxygenated blood) → umbilical arteries (medial
umbilical ligaments) → placenta
Just understand it :)
What are the 3 narrowed areas of the esophagus?
- Origin below pharynx (C6)
- Crossing of the left bronchus and aortic arch (T4)
- Esophageal opening at diaphragm
Structures related to/ compress on esophagus:
- Left bronchus (anterior)
- Aortic arch (left side)
- Left atrium (anterior surface of esophagus)
- Right pulmonary veins
The azygos system forms anastomoses between _____ and __________.
SVC and IVC
Azygos vein (right) , accessory hemiazygos vein (left) and hemiazygos vein (left) drain \_\_\_\_\_\_\_\_\_\_\_\_\_. They are paried/unpaired.
posterior intercostal veins;
unpaired
like a “K”
up stroke: accessory hemiazygous
down stroke: hemiazygous vein
七上八下 T7 T8
When portal circulation is impaired, blood bypasses the portal vein through ___________. One site of such
anastomoses is that of ________ and ______ at the esophagus. The increase in blood flow through
the anastomoses can cause varices and subsequently
hemorrhage.
The esophageal plexus then drain blood to the _______.
portal-systemic
anastomoses;
esophageal veins and left gastric vein.
Azygous vein
Azygos vein drains the __________.
Accessory hemiazygos vein drains the ________ .
Hemiazygos vein drains the_________ .
right thoracic wall;
left upper thoracic wall;
left lower thoracic wall
What can be a cause of portal hypertension in liver cirrhosis?
varicose of esophageal veins
What is the ligamentum arteriosum? What is its embryological significance? What is its
relation to the recurrent laryngeal nerve(s)?
Ligament between the pulmonary trunk and aorta
Remnant of ductus arteriosus, one of the fetal shunts
The left recurrent laryngeal nerve runs behind the ligamentum arteriosum
Where does the aorta first branch?
Coronary arteries (right above aortic cusps), not brachiocephalic trunk
